The DOI matches its Crossref record; 43 of the 43 references it cites were found in a registry or an index; 2 of the 91 sources its claims cite were checked for support.
Reappraisal of hydrocarbon biomarkers in Archean rocks
Open accessAbstract
Significance: The advent of oxygenic photosynthesis set the stage for the evolution of complex life on an oxygenated planet, but it is unknown when this transformative biochemistry emerged. The existing hydrocarbon biomarker record requires that oxygenic photosynthesis and eukaryotes emerged more than 300 million years before the Great Oxidation Event [∼2.4 billion years ago (Ga)]. We report that hopane and sterane concentrations measured in new ultraclean Archean drill cores from Australia are comparable to blank concentrations, yet their concentrations in the exteriors of conventionally collected cores of stratigraphic equivalence exceed blank concentrations by more than an order of magnitude due to surficial contamination. Consequently, previous hydrocarbon biomarker reports no longer provide valid evidence for the advent of oxygenic photosynthesis and eukaryotes by ∼2.7 Ga.
Overview
AI snapshot
Written from the paper’s full text.
TL;DR
New ultraclean Archean drill cores from the Pilbara Craton contain hopanes and steranes at or below blank/femtogram levels, whereas exteriors of conventionally drilled equivalent rocks are contaminated by these biomarkers. The authors conclude that previously reported Archean hydrocarbon biomarkers cannot be used as evidence for oxygenic photosynthesis and eukaryotes by ∼2.7 Ga.
Key findings
- In AIDP-2 and AIDP-3 rock extracts, hopanes and steranes were typically at or below femtogram detection limits; when detectable, total hopane was <37.9 pg per gram of rock and total sterane was <32.9 pg per gram of rock, comparable to blanks and negative controls. In hydropyrolysates, neither total hopane nor total sterane exceeded cumulative blank concentrations (<20 pg per gram of rock).
- In contrast, exteriors of conventionally drilled and curated RHDH2A rocks of stratigraphic equivalence reached 389.5 pg per gram of rock total hopane and 1,039 pg per gram of rock total sterane in the abstract; Table 1 lists RHDH2A sawed surfaces at 250 and 259 pg per gram hopane and 1,092 and 509 pg per gram sterane.
- PAHs and diamondoids exceeded blank concentrations, with individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores; the results text reports hydropyrolysate individual PAH concentrations up to 1,039 ng per gram of rock.
- The authors conclude that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons, so existing lipid biomarker evidence cannot support the emergence of oxygenic photosynthesis and eukaryotes by ∼2.7 Ga; no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation.
Methods
- Multilaboratory study of new Archean drill cores from the Pilbara Craton, Western Australia, drilled during the 2012 Agouron Institute Drilling Program using hydrocarbon-clean protocols; AIDP-1 provided negative control samples, while AIDP-2 and AIDP-3 recovered organic-rich sedimentary rocks.
- Rock extracts and hydropyrolysates were analyzed by gas chromatography–mass spectrometry in full scan and metastable reaction monitoring modes, with compound-specific carbon isotopic analyses and PAH/diamondoid measurements; interiors and exteriors of 10 biomarker target samples from AIDP-2 and 2 from AIDP-3 were analyzed for extractable hydrocarbons, and hydropyrolysates were analyzed from eight samples.
- Approximately 10–40 g of rock powder were extracted per sample; results were compared with blanks, negative controls, and a conventionally drilled RHDH2A core to assess contamination versus syngeneity.
Limitations
- Stated: only a single compound-specific isotopic measurement was possible for the 116.09 m sample, so analytical uncertainty and reproducibility are not well constrained; future studies are required to test the possible mixing observation; the biomolecular precursors of the PAHs and diamondoids are unknown; and duration of heating and organic matter type complicate direct conversions between vitrinite reflectance, H/C ratio, and burial temperature.
- Stated: no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration should screen for rocks with milder thermal histories.
- Evident from the text: the study focuses on the Pilbara Craton and specific AIDP/RHDH2A cores, so the absence of detectable syngenetic hopanes and steranes in these samples does not by itself rule out their preservation in all Archean rocks; the authors acknowledge this by calling for future exploration of less mature archives.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
35 Own result · 34 Not checked yet · 19 Own interpretation · 8 Own method · 1 Supported so far · 1 Partly supported · accuracy not yet measured
The cited sources support only part of this claim — read each source’s verdict below.
In the paper
“Consistent with earlier work (1,10,39,40), the bulk organic carbon was found to be anomalously 13 C-depleted, with δ 13 C values ranging from -32‰ to -50‰ (Fig. 2 and SI Appendix, Table S5).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites [1] source
- Not checked yetcites [10] source
- Partly supportedcites [39] sourceExperimental — accuracy not yet measured
The introductory section describes late Archean organic carbon as strongly ¹³C-depleted, including bulk organic matter. The Results report a −57‰ to −28‰ range for kerogen from the paper’s samples, not a −32‰ to −50‰ range for bulk organic carbon. The source therefore supports the depletion but not the claimed measurement and exact range. (LLM, conf=0.85)
- Not checked yetcites [40] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
The sources with a verdict support this claim; the rest weren’t checked yet, have no full text we could read, or their verdicts aren’t rated yet.
In the paper
“The HyPy hydrocarbon δ 13 C values reported here are, to our knowledge, the first compound-specific isotopic measurements that are in agreement with the strongly 13 C-depleted kerogens (δ 13 C bulk < -39‰) of the Neoarchean (1,10,39,40).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites [1] source
- Not checked yetcites [10] source
- Supportedcites [39] source
The Results report Neoarchean kerogen δ13C values ranging from −57‰ to −28‰, including values below −39‰. The source supports the cited point about strongly 13C-depleted kerogens; “the first compound-specific isotopic measurements” describes the citing authors’ own HyPy results, not a measurement attributed to this source. (LLM, conf=0.90)
- Not checked yetcites [40] source
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Furthermore, the hopane and sterane concentrations measured in our analysis of the RHDH2A sample are more compatible with the concentrations reported in earlier Archean biomarker studies of the Mount Bruce and Transvaal supergroups (7,21)”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plaincorrelationalSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The two samples containing alkanes also hosted the least thermally altered kerogens according to their atomic H/C ratios and pyrolysate polycyclic aromatic hydrocarbon (PAH) ratios.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plaincorrelationaln = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
None of the sources cited for this claim have been checked yet.
In the paper
“Moreover, extractable acyclic isoprenoids and a homologous series of extractable n-alkanes (C 10-23+ ), both of which were prominent in previous Archean biomarker studies (1-3, 5, 7, 22, 23), were also below detection limits or cumulative laboratory blank concentrations in the AIDP samples.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The same two samples also have the highest abundance of alkylated relative to nonalkylated PAH in the pyrolysates (SI Appendix, Table S10).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plaincorrelationaln = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit”
- Also stated in: § Results and Discussion · plain
“Hopanes and steranes in the rock extracts from AIDP-2 and AIDP-3 were typically at or below femtogram detection limits”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- Also stated in: § Results and Discussion · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“For example, the methylphenanthrene/phenanthrene (MP/P) ratios for these two samples were 1.0-1.2 compared with the other samples that have MP/P values ranging from 0.2 to 0.5.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plaincorrelationaln = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Systematic blank analyses using solvent rinses and sawed pieces of a combusted brick demonstrated that the diamond-rimmed blade used with the newly purchased, water-cooled saw constructed entirely of stainless steel and aluminum was a significant vector for hydrocarbon biomarker contamination.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Methods
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Similarly, they had methyl- pyrene/pyrene (MePy/Py) ratios of 0.4-0.6 compared with the other samples that have MePy/Py values close to 0.1.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
- It may state two separate claims as one. 26
- Probably not a substantial claim. 11
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, a series of C 10-20 n-alkanes (with a maximum abundance at C 13 ), methylalkanes, and alkylcyclohexanes were detected in hydropyrolysates from two carbonate-rich rocks at 116.09 m and 170.40 m in the Carawine Dolomite of AIDP-2 (SI Appendix, Fig. S6), yet acyclic isoprenoids were not detected in any of the hydropyrolysates.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The n-alkanes, hopanes, and steranes were enriched on the exterior of the RHDH2A core compared with the interior, where the total hopane and total sterane concentrations in the exterior exceeded the interior and blank concentrations by one to two orders of magnitude (Table 1 and Fig. 1).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plaincorrelationalSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Hopanes and steranes in the rock extracts from AIDP-2 and AIDP-3 were typically at or below femtogram detection limits, but if they were detectable, the total sterane and total hopane concentrations were comparable to blank and negative control concentrations (Table 1 and Fig. 1).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Most samples had H/C ratios of 0.19-0.35 (SI Appendix, Table S5), but these two samples have the highest H/C ratios of 0.54 and 0.46.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores.”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“As in the rock extracts, individual hopanes and steranes in the AIDP-2 and AIDP-3 hydropyrolysates were usually at or below detection limits, but when they were detected, neither the total hopane nor the total sterane concentrations exceeded cumulative blank concentrations (<20 pg per gram of rock).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plainn = 8- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The total n-alkane concentrations in these hydropyrolysates were two orders of magnitude higher than in laboratory blanks (<10 ng per gram of rock), in which methylalkane and alkylcyclohexane series were not detected.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Results and Discussion
plainn = 2- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This anomously 13 C-enriched sample was a 10-cm pyrobituminous stylocumulate occurring in stylolitic to brecciated dolarenite of the upper Carawine where dark insoluble matter concentrated as a result of pressure solution and carbonate dissolution (SI Appendix, Fig. S3).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plaindirectSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Many AIDP samples, however, host extractable PAHs and diamondoids with concentrations up to 80 ng per gram of rock and 4 ng per gram of rock, respectively (SI Appendix, Fig. S4).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“PAHs and diamondoids were also detected in the hydropyrolysates, where individual PAH concentrations were up to 1039 ng per gram of rock, and their concentrations were significantly higher than their corresponding HyPy blank concentrations of less than 1 ng per gram of rock for phenanthrene and pyrene (SI Appendix, Table S10).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“the analyses of the saw blade (before it was heat treated) and the sawed surfaces of the RHDH2A quarter-core highlight that sawing can contribute significant but variable hydrocarbon contaminants to the substrate, yet the cumulative blanks reported in previous studies did not record the hydrocarbon contribution from sawing (1,4,6,7).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“the PAH and diamondoid distributions in tandem with the H/C ratios confirm that these rocks are overmature and are within the prehnite-pumpellyite metamorphic facies (12,15,17,(36)(37)(38).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites 12,15,17,(36)(37)(38)
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Like the PAHs and diamondoids that previous studies reported in Archean rock extracts and hydropyrolysates (3,21,24,28), the low molecular mass aromatics (≤C 16 ) predominate over high molecular mass PAHs (>C 16 ), and nonalkylated parent PAHs are in greater abundance compared with alkylated PAH (SI Appendix, Figs.S4 and S5 and Tables S8 and S10).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“and they are the most 13 C-depleted organic molecules reported from Archean rocks, ranging from -42.6‰ to -45.9‰ (SI Appendix, Table S7).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Clearly, the hydrocarbons must have been present in, or added to, the RHDH2A quarter core before laboratory preparation.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
boosteddirectSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Each laboratory analyzed either a chert or igneous negative control sample from AIDP-2 or AIDP-1 for extractable hydrocarbons before the analyses of the biomarker target samples.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Methods
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“However, all results from all laboratories are consistent with the results described here.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Methods
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Spatially separated by less than 1 km, AIDP-2 and RHDH2A both intersect the Carawine Dolomite (<2.63 Ga) of the Hamersley Group and the Jeerinah Formation (2.63-2.67Ga) of the Fortescue Group (20), so they sample the same stratigraphy and have experienced the same regional metamorphic effects (Fig. 1).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Significance
What the sources say
- Not checked yetcites [20] source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“However, the interpretation of the Archean biomarker record has become controversial, with recent arguments for a nonsyngenetic origin of these hydrocarbons (10,11).”
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
In the paper
“According to previous studies of mineral assemblage and organic matter reflectivity, these zones are within the prehnite-pumpellyite metamorphic facies and anthracite coal rank, implying maximum burial temperatures and pressures of 200-300 °C and <7 kbar (1 bar = 100 kPa), respectively (15)(16)(17)(18).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Sample Collection
What the sources say
- Not checked yetcites (15)(16)(17)(18)
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial.”
What the sources say
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“PAHs and diamondoids were identified by comparison with published mass spectra, published relative retention times, and parallel analysis with standards.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Only a single compound-specific isotopic measurement was possible for this sample, so the analytical uncertainty and reproducibility are not well constrained.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plaindirectSingle case- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“Instead, contamination is the only explanation for the reproducibility of the detectable surficial hopanes and steranes in conventionally drilled and curated Archean samples (3,6,7,11) and the undetectable or blank level-equivalent hopane and sterane concentrations in samples from the ultraclean AIDP drill cores.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
boosteddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Two hypotheses have been proposed to explain surficial biomarker enrichments in Archean drill core: contamination and the live oil effect (i.e., the outward migration of hydrocarbons due to drill core depressurization during recovery) (11).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites [11] source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
In the paper
“Lastly, the extractable PAHs could be syngenetic but heavily altered by reactions between hydrothermal fluids and the bitumen (28), but this mechanism may not be able to account for the full >10‰ 13 C enrichment.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites [28] source
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: unclear — It is unclear whether the paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
In the paper
“Previous work suggests that the Jeerinah Formation and other organic-rich Archean shales generated and expelled petroleum (17)”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
What the sources say
- Not checked yetcites [17] source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“which is a critical proof of concept for Precambrian organic geochemistry that had never been directly demonstrated before this work, to our knowledge.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
hedged- Asserted: passes — The authors put it forward as true.
- Checkable: fails — It may be too vague to check against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may be too vague to check against evidence.
None of the sources cited for this claim have been checked yet.
In the paper
“and that the Pilbara Craton, including the Ripon Hills region, has experienced multiple episodes of hydrothermal fluid flow, particularly around the time of peak regional metamorphism at ∼2.1 Ga (18,41).”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
plaincorrelational- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, hydrothermal fluids could account for PAH migration from its original source, where this second generation of migrated overmature hydrothermal PAHs would have diluted or replaced the primary bitumens.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“suggesting that the kerogens of the Jeerinah Formation and Carawine Dolomite may not necessarily be the primary source of the cooccurring extractable PAHs, despite strong evidence of indigeneity.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
hedgedconditional- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The carbon isotopic anomaly at 2.6–2.7 Ga is a reliable stratigraphic marker for comparing AIDP bulk organic δ13C.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Alternatively, lateral oil migration before peak metamorphism could have introduced the extractable organic matter with isotopic compositions distinct from the associated kerogen.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
hedgedconditional- Asserted: fails — The authors may not put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: fails — The paper may give no reason why it holds.
Probably not a substantial claim. The authors may not put it forward as true. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.
The paper relies on this without support.
Laboratory blanks and negative controls capture all hydrocarbon contamination relevant to the AIDP samples.
“Hopanes and steranes in the rock extracts from AIDP-2 and AIDP-3 were typically at or below femtogram detection limits, but if they were detectable, the total sterane and total hopane concentrations were comparable to blank and negative control concentrations”
“Instead, contamination is the only explanation for the reproducibility of the detectable surficial hopanes and steranes in conventionally drilled and curated Archean samples (3,6,7,11) and the undetectable or blank level-equivalent hopane and sterane concentrations in samples from the ultraclean AIDP drill cores.”
The paper relies on this without support.
Hydropyrolysis releases kerogen-bound organic matter without significant carbon isotopic fractionation.
“The isotopic match between the AIDP bulk organic matter and the hydropyrolysate PAHs supports a syngenetic origin for the hydropyrolysate PAHs generated by thermochemical cleavage of covalent bonds within the host kerogens.”
The paper relies on this without support.
The carbon isotopic anomaly at 2.6–2.7 Ga is a reliable stratigraphic marker for comparing AIDP bulk organic δ13C.
“In contrast, the δ 13 C values of extractable PAHs do not covary with the AIDP bulk organic δ 13 C through the carbon isotopic anomaly at 2.6-2.7 Ga”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The cited source says what the claim attributes to it.
In the citing paper
“Until recently the earliest organic biomarker evidence for eukaryotic sterol synthesis was dated to 2.7 Ga (Brocks et al., 1999), but those records have now been convincingly tied to contamination (French et al., 2015).”
From Oxygenation, Life, and the Planetary System during Earth's Middle History: An Overview (2021) · cites this paper as French et al., 2015
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
Each contradiction between two passages listed here was confirmed by an independent check.
Rated minor: it would not touch a result — a value no result rests on, a p-value that stays on the same side of the significance level, or a conflict that is clerical, resolved elsewhere in the paper, or outside its own findings.
In the paper
§ Reappraisal of hydrocarbon biomarkers in Archean rocks
“when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > †
“| AIDP-2 197.20 m | nd | nd | 50.4 | 49.4 |”
Citations
Cites
Petroleum Formation and Occurrence
Tissot, B. P., & Welte, D. H. (1978) · Springer eBooks · doi:10.1007/978-3-642-96446-6 · Cited by 6,480
The rise of oxygen in Earth's early ocean and atmosphere
Lyons, T. W., Reinhard, C. T., & Planavsky, N. J. (2014) · Nature · doi:10.1038/nature13068 · Cited by 2,810
Dating the rise of atmospheric oxygen
Bekker, A., Holland, H. D., Wang, P.-L., Rumble, D., Stein, H. J., Hannah, J. L., Coetzee, L. L., & Beukes, N. J. (2004) · Nature · doi:10.1038/nature02260 · Cited by 1,435
Archean Molecular Fossils and the Early Rise of Eukaryotes
Brocks, J. J., Logan, G. A., Buick, R., & Summons, R. E. (1999) · Science · doi:10.1126/science.285.5430.1033 · Cited by 1,275
Self-citationA Whiff of Oxygen Before the Great Oxidation Event?
Anbar, A. D., Duan, Y., Lyons, T. W., Arnold, G. L., Kendall, B., Creaser, R. A., Kaufman, A. J., Gordon, G. W., Scott, C., Garvin, J., et al. (2007) · Science · doi:10.1126/science.1140325 · Cited by 1,024
Self-citationWaples, D. (1980) · AAPG Bulletin · doi:10.1306/2f9193d2-16ce-11d7-8645000102c1865d · Cited by 774
A chemical kinetic model of vitrinite maturation and reflectance
Burnham, A. K., & Sweeney, J. J. (1989) · Geochimica et Cosmochimica Acta · doi:10.1016/0016-7037(89)90136-1 · Cited by 664
Reassessing the first appearance of eukaryotes and cyanobacteria
Rasmussen, B., Fletcher, I. R., Brocks, J. J., & Kilburn, M. R. (2008) · Nature · doi:10.1038/nature07381 · Cited by 612
Self-citationEvaluation of petroleum generation by hydrous phrolysis experimentation
Lewan, M. D. (1985) · Philosophical Transactions of the Royal Society of London Series A Mathematical and Physical Sciences · doi:10.1098/rsta.1985.0033 · Cited by 444
Brocks, J. J., Buick, R., Summons, R. E., & Logan, G. A. (2003) · Geochimica et Cosmochimica Acta · doi:10.1016/s0016-7037(03)00209-6 · Cited by 306
Self-citation
Cited by
Sorted by citations
The rise of algae in Cryogenian oceans and the emergence of animals
Brocks, J. J., Jarrett, A. J. M., Sirantoine, E., Hallmann, C., Hoshino, Y., & Liyanage, T. (2017) · Nature · doi:10.1038/nature23457 · Cited by 574
Self-citationCatling, D. C., & Zahnle, K. J. (2020) · Science Advances · doi:10.1126/sciadv.aax1420 · Cited by 568
Evolution of Oxygenic Photosynthesis
Fischer, W. W., Hemp, J., & Johnson, J. E. (2016) · Annual Review of Earth and Planetary Sciences · doi:10.1146/annurev-earth-060313-054810 · Cited by 438
The evolution of Earth's biogeochemical nitrogen cycle
Stüeken, E. E., Kipp, M. A., Koehler, M. C., & Buick, R. (2016) · Earth-Science Reviews · doi:10.1016/j.earscirev.2016.07.007 · Cited by 446
“However, there is no strong evidence that eukaryotes existed at this time (French et al., 2015).”
Self-citationThe aerobic diagenesis of Mesoproterozoic organic matter
Wang, X., Zhao, W., Zhang, S., Wang, H., Su, J., Canfield, D. E., & Hammarlund, E. U. (2018) · Scientific Reports · doi:10.1038/s41598-018-31378-6 · Cited by 431
Early photosynthetic eukaryotes inhabited low-salinity habitats
Sánchez‐Baracaldo, P., Raven, J. A., Pisani, D., & Knoll, A. H. (2017) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1620089114 · Cited by 332
“7 Ga eukaryotes have now been reinterpreted as younger contaminants (15, 16).”
BackgroundChallenges in evidencing the earliest traces of life
Javaux, E. J. (2019) · Nature · doi:10.1038/s41586-019-1436-4 · Cited by 297
Bengtson, S., Sallstedt, T., Belivanova, V., & Whitehouse, M. (2017) · PLOS Biology · doi:10.1371/journal.pbio.2000735 · Cited by 284
“In spite of subsequent attempts to identify Archaean eukaryote biomarkers, all such evidence for eukaryote presence is now considered invalid, not only because of contamination issues [44] but also because the putative Archaean steranes that were taken as proxies for eukaryotic membrane sterols may also derive from no…”
BackgroundNeveu, M. F., Hays, L. E., Voytek, M. A., New, M. H., & Schulte, M. D. (2018) · Astrobiology · doi:10.1089/ast.2017.1773 · Cited by 299
“…(Schopf, 1993; Mojzsis et al., 1996; Summons et al., 1999), and beyond Earth (Levin and Straat 1977; McKay et al., 1996) have been debated to this day (M.D. Brasier et al., 2002, 2015; van Zullen et al., 2002; Lepland et al., 2005; Martel et al., 2012; French et al., 2015; Levin and Straat, 2016).”
BackgroundResultInfluentialCyanobacteria evolution: Insight from the fossil record
Demoulin, C., Lara, Y. J., Cornet, L., François, C., Baurain, D., Wilmotte, A., & Javaux, E. (2019) · Free Radical Biology and Medicine · doi:10.1016/j.freeradbiomed.2019.05.007 · Cited by 239
Trace elements at the intersection of marine biological and geochemical evolution
Robbins, L. J., Lalonde, S. V., Planavsky, N. J., Partin, C. A., Reinhard, C. T., Kendall, B., Scott, C., Hardisty, D. S., Gill, B. C., Alessi, D. S., et al. (2016) · Earth-Science Reviews · doi:10.1016/j.earscirev.2016.10.013 · Cited by 227
“contamination by younger material to explain their origins (e.g., carbon isotopes: van Zuilen et al., 2002; Lepland et al., 2011; microfossils: Brasier et al., 2002; Garcia-Ruiz et al., 2003; ichnofossils: Grosch and McLoughlin, 2014; stromatolites: Lowe, 1994; biomarkers: Rasmussen et al., 2008; French et al., 2015).”
BackgroundLife: the first two billion years
Knoll, A. H., Bergmann, K., & Strauss, J. V. (2016) · Philosophical Transactions of the Royal Society B Biological Sciences · doi:10.1098/rstb.2015.0493 · Cited by 218
Oxygenation, Life, and the Planetary System during Earth's Middle History: An Overview
Lyons, T. W., Diamond, C. W., Planavsky, N. J., Reinhard, C. T., & Li, C. (2021) · Astrobiology · doi:10.1089/ast.2020.2418 · Cited by 211
“, 1999), but those records have now been convincingly tied to contamination (French et al., 2015).”
BackgroundResultInfluentialCrown group Oxyphotobacteria postdate the rise of oxygen
Shih, P. M., Hemp, J., Ward, L. M., Matzke, N. J., & Fischer, W. W. (2016) · Geobiology · doi:10.1111/gbi.12200 · Cited by 174
Hamilton, T. L., Bryant, D. A., & Macalady, J. L. (2015) · Environmental Microbiology · doi:10.1111/1462-2920.13118 · Cited by 197
“In addition, recent analyses indicate that previously sampled Archean sedimentary rocks host biomarker contaminants accumulated during sample collection and processing and overmature hydrocarbons (French et al., 2015).”
BackgroundSignatures of early microbial life from the Archean (4 to 2.5 Ga) eon
Lepot, K. (2020) · Earth-Science Reviews · doi:10.1016/j.earscirev.2020.103296 · Cited by 189
“Most importantly, the same biomarkers were absent during analysis of recent cores drilled in contamination-limiting conditions (French et al., 2015).”
The NASA Mars 2020 Rover Mission and the Search for Extraterrestrial Life
Williford, K. H., Farley, K. A., Stack, K. M., Allwood, A. C., Beaty, D., Beegle, L. W., Bhartia, R., Brown, A. J., Juárez, M. D. L. T., Hamran, S., et al. (2018) · Elsevier eBooks · doi:10.1016/b978-0-12-809935-3.00010-4 · Cited by 175
Cyanobacterial evolution during the Precambrian
Schirrmeister, B. E., Sánchez‐Baracaldo, P., & Wacey, D. (2016) · International Journal of Astrobiology · doi:10.1017/s1473550415000579 · Cited by 165
Sedimentary Ce anomalies: Secular change and implications for paleoenvironmental evolution
Zhang, K., & Shields, G. (2022) · Earth-Science Reviews · doi:10.1016/j.earscirev.2022.104015 · Cited by 162
Rapid, direct and non-destructive assessment of fossil organic matter via microRaman spectroscopy
Ferralis, N., Matys, E. D., Knoll, A. H., Hallmann, C., & Summons, R. E. (2016) · Carbon · doi:10.1016/j.carbon.2016.07.039 · Cited by 158
“volatilization and pyrolysis approaches for detection that have so far been deployed in landed missions [9-12].”
BackgroundSelf-citationJavaux, E. J., & Lepot, K. (2018) · Earth-Science Reviews · doi:10.1016/j.earscirev.2017.10.001 · Cited by 158
“Recently, the biomarker evidence for cyanobacteria (and eukaryotes) in Archean rocks (Brocks et al., 2003; Eigenbrode et al., 2008) was reassessed as contamination (French et al., 2015; Rasmussen et al., 2008).”
BackgroundInfluentialEukaryogenesis and oxygen in Earth history
Mills, D. B., Boyle, R. A., Daines, S. J., Sperling, E. A., Pisani, D., Donoghue, P. C. J., & Lenton, T. M. (2022) · Nature Ecology & Evolution · doi:10.1038/s41559-022-01733-y · Cited by 156
“The oldest claims for eukaryotes are Archaean (4.0 to 2.5 Ga) and early Palaeoproterozoic (2.5 to 1.6 Ga), including 2.7-billion-year-old sterol biomarkers 71 that have since been rejected as younger contaminants 72,73 , along with all claims of eukaryote biomarkers prior to around 0.8 Ga 74,75 .”
InfluentialOrigin of microbial biomineralization and magnetotaxis during the Archean
Lin, W., Paterson, G. A., Zhu, Q., Wang, Y., Kopylova, E., Li, Y., Knight, R. D., Bazylinski, D. A., Zhu, R., Kirschvink, J. L., et al. (2017) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1614654114 · Cited by 134
“However, the biomarkers upon which those inferences were based are now known to be contaminants (25).”
BackgroundOn the co‐evolution of surface oxygen levels and animals
Cole, D. B., Mills, D. B., Erwin, D. H., Sperling, E. A., Porter, S. M., Reinhard, C. T., & Planavsky, N. J. (2020) · Geobiology · doi:10.1111/gbi.12382 · Cited by 141
“Work on the Precambrian biomarker record provides a cautionary tale highlighting the need to constantly revisit sedimentary records—over the past decade there was a realization that most of the biomarker record was heavily influenced by contamination (Brocks, 2018; French et al., 2015).”
BackgroundLost world of complex life and the late rise of the eukaryotic crown
Brocks, J. J., Nettersheim, B. J., Adam, P., Schaeffer, P., Jarrett, A. J. M., Güneli, N., Liyanage, T., van Maldegem, L. M., Hallmann, C., & Hope, J. M. (2023) · Nature · doi:10.1038/s41586-023-06170-w · Cited by 135
Self-citationThe changing view of eukaryogenesis – fossils, cells, lineages and how they all come together
Dacks, J. B., Field, M. C., Buick, R., Eme, L., Gribaldo, S., Roger, A. J., Brochier‐Armanet, C., & Devos, D. P. (2016) · Journal of Cell Science · doi:10.1242/jcs.178566 · Cited by 131
“This has now been confirmed by an analysis of a new drill-core that was obtained using ultraclean drilling and sampling techniques from a site alongside the original core that yielded the highest sterane concentrations (French et al., 2015).”
MethodSelf-citationScott, C., Slack, J., & Kelley, K. (2017) · Chemical Geology · doi:10.1016/j.chemgeo.2017.01.026 · Cited by 123
Co‐evolution of early Earth environments and microbial life
Lyons, T. W., Tino, C., Fournier, G. P., Anderson, R. E., Leavitt, W. D., Konhauser, K. O., & Stüeken, E. E. (2024) · Nature Reviews Microbiology · doi:10.1038/s41579-024-01044-y · Cited by 141
“…iron oxidizers 16 , fossil and organic molecular records provide little insight into the early microbial metabolisms during the Archaean, obscured in large part by the poor preservation states of the very old, often deeply buried and tectonically and metamorphically overprinted host rocks 17 .”
Paleoproterozoic sterol biosynthesis and the rise of oxygen
Gold, D. A., Caron, A., Fournier, G. P., & Summons, R. E. (2017) · Nature · doi:10.1038/nature21412 · Cited by 129
Self-citationEarly Microbial Evolution: The Age of Anaerobes
Martin, W. F., & Sousa, F. L. (2016) · Cold Spring Harbor Perspectives in Biology · doi:10.1101/cshperspect.a018127 · Cited by 129
“2008), and more recently taken back altogether by its original senior authors (French et al. 2015).”
BackgroundSperling, E. A., & Stockey, R. G. (2018) · Integrative and Comparative Biology · doi:10.1093/icb/icy088 · Cited by 122
Proterozoic photosynthesis – a critical review
Butterfield, N. J. F. (2015) · Palaeontology · doi:10.1111/pala.12211 · Cited by 120
“None of these protistan groups has an unambiguous pre-Mesozoic fossil record, although sterane biomarkers point to a marine biological pump dominated by eukaryotes through the whole of the Phanerozoic (Summons et al. 1999).”
BackgroundInfluentialLipid biomarkers: molecular tools for illuminating the history of microbial life
Summons, R. E., Welander, P. V., & Gold, D. A. (2021) · Nature Reviews Microbiology · doi:10.1038/s41579-021-00636-2 · Cited by 115
Self-citationReactive Oxygen Species: Radical Factors in the Evolution of Animal Life
Taverne, Y. J. H. J., Merkus, D., Bogers, A. J. J. C., Halliwell, B. B., Duncker, D. J., & Lyons, T. W. (2018) · BioEssays · doi:10.1002/bies.201700158 · Cited by 110
Lipid biomarkers for the reconstruction of deep-time environmental conditions
Luo, G., Yang, H., Algeo, T. J., Hallmann, C., & Xie, S. (2018) · Earth-Science Reviews · doi:10.1016/j.earscirev.2018.03.005 · Cited by 112
Self-citationBrocks, J. J., Jarrett, A. J. M., Sirantoine, E., Kenig, F., Moczydłowska, M., Porter, S., & Hope, J. (2016) · Geobiology · doi:10.1111/gbi.12165 · Cited by 109
“Drilling, cutting, storage, and simple subaerial exposure can introduce anthropogenic hydrocarbons that may permeate centimeters deep into rock, obscuring any indigenous biomarker component (Brocks et al., 2003, 2008; Rasmussen et al., 2008; Brocks, 2011; French et al., 2015).”
BackgroundResultSelf-citationPaleo-Rock-Hosted Life on Earth and the Search on Mars: A Review and Strategy for Exploration
Onstott, T. C., Ehlmann, B. L., Sapers, H. M., Coleman, M., Ivarsson, M., Marlow, J. J., Neubeck, A., & Niles, P. (2019) · Astrobiology · doi:10.1089/ast.2018.1960 · Cited by 121
“However, aliphatic and polycyclic lipids in the metamorphosed Archean sediments containing polyaromatic hydrocarbons were later shown to be drilling contamination (French et al., 2015).”
BackgroundSpence, G. H., Heron, D. P. L., & Fairchild, I. J. (2016) · Sedimentology · doi:10.1111/sed.12261 · Cited by 105
“Earlier finds of Archaean biomarkers are now discredited and shown to result from contamination, and it is now thought that all Archaean rocks are too thermally mature to preserve biomarkers (French et al., 2015); this applies also to the vast majority of Neoproterozoic sections.”
BackgroundAlbut, G., Babechuk, M. G., Kleinhanns, I. C., Benger, M., Beukes, N. J., Steinhilber, B., Smith, A. J. B., Kruger, S. J., & Schoenberg, R. (2018) · Geochimica et Cosmochimica Acta · doi:10.1016/j.gca.2018.02.034 · Cited by 103
Tracking the rise of eukaryotes to ecological dominance with zinc isotopes
Isson, T. T., Love, G. D., Dupont, C. L., Reinhard, C. T., Zumberge, A. J., Asael, D., Gueguen, B., McCrow, J., Gill, B. C., Owens, J., et al. (2018) · Geobiology · doi:10.1111/gbi.12289 · Cited by 101
“…analytical methodologies to minimize contamination, suggests that the earliest detectable and robust eukaryotic (24- alkylated) sterane biomarkers appear sometime within the Neoproterozoic Era (<1000 Ma) (e.g., Brocks et al., 2015, 2017; French et al., 2015; Love et al., 2009) (see Appendix S1).”
BackgroundSelf-citationEarth's First Redox Revolution
Ostrander, C. M., Johnson, A. C., & Anbar, A. D. (2021) · Annual Review of Earth and Planetary Sciences · doi:10.1146/annurev-earth-072020-055249 · Cited by 102
A Mesoproterozoic iron formation
Canfield, D. E., Zhang, S., Wang, H., Wang, X., Zhao, W., Su, J., Bjerrum, C. J., Haxen, E. R., & Hammarlund, E. U. (2018) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1720529115 · Cited by 100
“We believe these TMAIs to be indigenous based on analysis of inside and outside pieces of core (71) (SI Materials and Methods).”
BackgroundLuo, Q., George, S. C., Xu, Y., & Zhong, N. (2016) · Organic Geochemistry · doi:10.1016/j.orggeochem.2016.05.004 · Cited by 95
Self-citationPutative sponge biomarkers in unicellular Rhizaria question an early rise of animals
Nettersheim, B. J., Brocks, J. J., Schwelm, A., Hope, J. M., Not, F., Lomas, M. W., Schmidt, C., Schiebel, R., Nowack, E. C. M., Patrick De Deckker, B., et al. (2019) · Nature Ecology & Evolution · doi:10.1038/s41559-019-0806-5 · Cited by 90
Self-citationGarcía‐Pichel, F., Lombard, J., Soule, T. T., Dunaj, S., Wu, S., & Wojciechowski, M. F. (2019) · mBio · doi:10.1128/mbio.00561-19 · Cited by 89
“We also avoided using dates derived from molecular fossils (hopanoids), as these have recently been discredited (34).”
Differential metamorphic effects on nitrogen isotopes in kerogen extracts and bulk rocks
Stüeken, E. E., Lima-Zaloumis, J., Meixnerová, J., & Buick, R. (2017) · Geochimica et Cosmochimica Acta · doi:10.1016/j.gca.2017.08.019 · Cited by 91
“5 for the Jeerinah Formation agree with recent RockEval evidence for metamorphic alteration to lower greenschist facies (French et al., 2015).”
BackgroundMethodInfluentialSelf-citationMercury isotope signatures record photic zone euxinia in the Mesoproterozoic ocean
Zheng, W., Gilleaudeau, G. J., Kah, L. C., & Anbar, A. D. (2018) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1721733115 · Cited by 95
“For example, contamination from anthropogenic petroleum-based hydrocarbons has been found to be pervasive in many published Precambrian biomarker data (6, 7).”
BackgroundEvolution of the structure and impact of Earth’s biosphere
Planavsky, N. J., Crowe, S. A., Fakhraee, M., Beaty, B., Reinhard, C. T., Mills, B. J. W., Holstege, C., & Konhauser, K. O. (2021) · Nature Reviews Earth & Environment · doi:10.1038/s43017-020-00116-w · Cited by 102
Ward, L. M., & Shih, P. M. (2019) · Free Radical Biology and Medicine · doi:10.1016/j.freeradbiomed.2019.01.049 · Cited by 80
Biogeochemical Transformations in the History of the Ocean
Lenton, T. M., & Daines, S. J. (2016) · Annual Review of Marine Science · doi:10.1146/annurev-marine-010816-060521 · Cited by 80
Cryogenian evolution of stigmasteroid biosynthesis
Hoshino, Y., Stroeva, A. R., Meredith, W., Snape, C. E., Poshibaev, V. V., Versteegh, G. J. M., Kuznetsov, N. B., Leider, A., van Maldegem, L. M., Neumann, M., et al. (2017) · Science Advances · doi:10.1126/sciadv.1700887 · Cited by 77
Self-citationTransient surface ocean oxygenation recorded in the ∼2.66-Ga Jeerinah Formation, Australia
Koehler, M. C., Buick, R., Kipp, M. A., Stüeken, E. E., & Zaloumis, J. (2018) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1720820115 · Cited by 72
“Rocks from both AIDP-2 and AIDP-3 are generally thought to be within the prehnite–pumpellyite metamorphic facies (37), but an alternative upper greenschist facies interpretation exists (38).”
BackgroundSelf-citationZumberge, J. A., Rocher, D., & Love, G. D. (2020) · Geobiology · doi:10.1111/gbi.12378 · Cited by 73
“Blank HyPy runs with the steel wool ball loaded in the reactor tube were run to verify that the batch of steel wool was free of contamination, as described in French et al. (2015).”
BackgroundMethodInfluentialSelf-citationThe transition from a cyanobacterial to algal world and the emergence of animals
Brocks, J. J. (2018) · Emerging Topics in Life Sciences · doi:10.1042/etls20180039 · Cited by 74
Self-citationNutman, A. P., Bennett, V. C., Friend, C. R. L., Kranendonk, M. J. V., Rothacker, L., & Chivas, A. R. (2019) · Precambrian Research · doi:10.1016/j.precamres.2019.105347 · Cited by 73
Williford, K. H., Ushikubo, T., Lepot, K., Kitajima, K., Hallmann, C., Spicuzza, M. J., Kozdon, R., Eigenbrode, J. L., Summons, R. E., & Valley, J. W. (2015) · Geobiology · doi:10.1111/gbi.12163 · Cited by 69
Self-citationTempleton, A. S., Ellison, E. T., Glombitza, C., Morono, Y., Rempfert, K. R., Hoehler, T. M., Zeigler, S. D., Kraus, E., Spear, J. R., Nothaft, D. B., et al. (2021) · Journal of Geophysical Research Biogeosciences · doi:10.1029/2021jg006315 · Cited by 68
COHEN, P. A., & Kodner, R. B. (2021) · Trends in Ecology & Evolution · doi:10.1016/j.tree.2021.11.005 · Cited by 65
A Mesoarchean shift in uranium isotope systematics
Wang, X., Planavsky, N. J., Hofmann, A., Saupe, E. E., Corte, B. P. D., Philippot, P., Lalonde, S. V., Jemison, N., Zou, H., Ossa, F. O., et al. (2018) · Geochimica et Cosmochimica Acta · doi:10.1016/j.gca.2018.07.024 · Cited by 67
The Telomere Paradox: Stable Genome Preservation with Rapidly Evolving Proteins
Saint‐Leandre, B., & Levine, M. T. (2020) · Trends in Genetics · doi:10.1016/j.tig.2020.01.007 · Cited by 51
Delarue, F., Rouzaud, J., Derenne, S., Bourbin, M., Westall, F., Kremer, B., Sugitani, K., Deldicque, D., & Robert, F. (2016) · Astrobiology · doi:10.1089/ast.2015.1392 · Cited by 63
“While non-Archean samples can be seen to dominate the first stage, the second stage mostly consists of the Archean samples.”
BackgroundZhao, W., Wang, X., Hu, S., Zhang, S., Wang, H., Guan, S., Ye, Y., Ren, R., & Wang, T. (2019) · Science China Earth Sciences · doi:10.1007/s11430-018-9312-4 · Cited by 63
Duda, J., Thiel, V., Bauersachs, T., Mißbach, H., Reinhardt, M., Schäfer, N., Kranendonk, M. J. V., & Reitner, J. (2018) · Biogeosciences · doi:10.5194/bg-15-1535-2018 · Cited by 68
“…been observed in other hydropyrolysates from Archaean kerogens that experienced low-grade metamorphism (Brocks et al., 2003b; Marshall et al., 2007; French et al., 2015). all of these cases, the degree of alkylation varied with the exact thermal alteration of the respective kerogens (Marshall et…”
InfluentialSchuler, C. G., Havig, J. R., & Hamilton, T. L. (2017) · Frontiers in Earth Science · doi:10.3389/feart.2017.00097 · Cited by 60
“Recently, biosignature records of Archean rocks have been called in to question due to contamination (French et al., 2015) whereas similar morphologies exist in drastically different environments.”
BackgroundRevolutions in energy input and material cycling in Earth history and human history
Lenton, T. M., Pichler, P., & Weisz, H. (2016) · Earth System Dynamics · doi:10.5194/esd-7-353-2016 · Cited by 69
“7 Ga now rejected (Rasmussen et al., 2008; French et al., 2015), and molecular clocks suggesting a last common ancestor 1.”
BackgroundNguyen, K. D., Love, G. D., Zumberge, J. A., Kelly, A. E., Owens, J. D., Rohrssen, M., Bates, S. M., Cai, C., & Lyons, T. W. (2019) · Geobiology · doi:10.1111/gbi.12329 · Cited by 56
“Blank HyPy runs were confirmed to be clean and free of contamination, as described in French et al. (2015).”
BackgroundMethodSelf-citationThe next frontier for planetary and human exploration
Stamenković, V., Beegle, L. W., Zacny, K. A., Arumugam, D. D., Baglioni, P., Barba, N. J., Baross, J. A., Bell, M. S., Bhartia, R., Blank, J. G., et al. (2019) · Nature Astronomy · doi:10.1038/s41550-018-0676-9 · Cited by 54
Hickman‐Lewis, K., Cavalazzi, B., Sorieul, S., Gautret, P., Foucher, F., Whitehouse, M. J., Jeon, H., Georgelin, T., Cockell, C. S., & Westall, F. (2020) · Scientific Reports · doi:10.1038/s41598-020-61774-w · Cited by 60
No evidence for high atmospheric oxygen levels 1,400 million years ago
Planavsky, N., Cole, D., Reinhard, C., Diamond, C., Love, G., Luo, G., Zhang, S., Konhauser, K., & Lyons, T. (2016) · Proceedings of the National Academy of Sciences of the United States of America · doi:10.1073/pnas.1601925113 · Cited by 53
Self-citationCellular and Molecular Biological Approaches to Interpreting Ancient Biomarkers
Newman, D. K., Neubauer, C., Ricci, J., Wu, C.-H., & Pearson, A. (2016) · Annual Review of Earth and Planetary Sciences · doi:10.1146/annurev-earth-050212-123958 · Cited by 50
Organic geochemical approaches to understanding early life
Alléon, J., & Summons, R. E. (2019) · Free Radical Biology and Medicine · doi:10.1016/j.freeradbiomed.2019.03.005 · Cited by 55
Self-citationVinnichenko, G., Jarrett, A. J. M., Hope, J. M., & Brocks, J. J. (2020) · Geobiology · doi:10.1111/gbi.12390 · Cited by 52
“Even relatively mild thermal alteration beneath prehnite–pumpellyite facies is incompatible with the preservation of biomarkers (French et al., 2015).”
BackgroundSelf-citationControls on O2Production in Cyanobacterial Mats and Implications for Earth's Oxygenation
Dick, G. J., Grim, S. L., & Klatt, J. M. (2018) · Annual Review of Earth and Planetary Sciences · doi:10.1146/annurev-earth-082517-010035 · Cited by 47
French, K. L., Birdwell, J. E., & Berg, M. D. V. (2020) · Geochimica et Cosmochimica Acta · doi:10.1016/j.gca.2020.01.053 · Cited by 49
Self-citationVeenman, L., Vainshtein, A., Yasin, N., Azrad, M., & Gavish, M. (2016) · International Journal of Molecular Sciences · doi:10.3390/ijms17060880 · Cited by 52
Sehlmeyer, K., Ruwisch, J., Roldán, N., & López-Rodríguez, E. (2020) · Frontiers in Physiology · doi:10.3389/fphys.2020.00386 · Cited by 46
Jarrett, A. J. M., Cox, G. M., Brocks, J. J., Grosjean, E., Boreham, C. J., & Edwards, D. S. (2019) · Geobiology · doi:10.1111/gbi.12331 · Cited by 47
“More recently, it has been acknowledged that anthropogenic hydrocarbon contamination introduced to rock samples during drilling, saw- cutting and storage can overprint the indigenous hydrocarbon signature (Brocks, Grosjean, & Logan, 2008; French et al., 2015; Grosjean & Logan, 2007).”
BackgroundSelf-citationBiomolecules from Fossilized Hot Spring Sinters: Implications for the Search for Life on Mars
Teece, B. L., George, S. C., Djokic, T., Campbell, K. A., Ruff, S. W., & Kranendonk, M. J. V. (2020) · Astrobiology · doi:10.1089/ast.2018.2018 · Cited by 43
Self-citationTesting the preservation of biomarkers during experimental maturation of an immature kerogen
Mißbach, H., Duda, J., Lünsdorf, N. K., Schmidt, B. C., & Thiel, V. (2016) · International Journal of Astrobiology · doi:10.1017/s1473550416000069 · Cited by 44
“As this range represents the end of catagenesis (*150°C in natural systems), the preservation of biomarkers in Precambrian rocks that experienced extensive metamorphism should be the exception (see e.g. French et al. 2015).”
BackgroundWeathering, alteration and reconstructing Earth's oxygenation
Planavsky, N. J., Robbins, L. J., Kamber, B. S., & Schoenberg, R. (2020) · Interface Focus · doi:10.1098/rsfs.2019.0140 · Cited by 45
“On a less positive note, even after clear guidelines for clean Precambrian biomarker work were published [47] claims of Precambrian biomarkers using older protocols were published (e.”
BackgroundEukaryotic red and green algae populated the tropical ocean 1400 million years ago
Zhang, S., Su, J., Ma, S., Wang, H., Wang, X., He, K., Wang, H., & Canfield, D. E. (2021) · Precambrian Research · doi:10.1016/j.precamres.2021.106166 · Cited by 44
Kusch, S., & Rush, D. (2022) · Organic Geochemistry · doi:10.1016/j.orggeochem.2022.104469 · Cited by 42
Regulation of Mitochondrial, Cellular, and Organismal Functions by TSPO
Gavish, M., & Veenman, L. (2017) · Advances in pharmacology · doi:10.1016/bs.apha.2017.09.004 · Cited by 49
Marin‐Carbonne, J., Rémusat, L., Sforna, M.-C., Thomazo, C., Cartigny, P., & Philippot, P. (2018) · Geobiology · doi:10.1111/gbi.12275 · Cited by 50
“Regional metamorphic temperature was estimated between 100 and 300°C (Lepot, Benzerara, Brown, & Philippot, 2008), which is too high for the preservation of hydrocarbon biomarkers (French et al., 2015).”
BackgroundYoung, G. M. (2018) · Earth-Science Reviews · doi:10.1016/j.earscirev.2018.12.013 · Cited by 44
van Maldegem, L. M., Sansjofre, P., Weijers, J. W. H., Wolkenstein, K., Strother, P. K., Wörmer, L., Hefter, J., Nettersheim, B. J., Hoshino, Y., Schouten, S., et al. (2019) · Nature Communications · doi:10.1038/s41467-019-08306-x · Cited by 45
Self-citationThe occurrence of 2‐methylhopanoids in modern bacteria and the geological record
Naafs, B. D. A., Bianchini, G., Monteiro, F., & Sánchez‐Baracaldo, P. (2021) · Geobiology · doi:10.1111/gbi.12465 · Cited by 40
“…1999), Matinenda Fm (2.45 Gyr) (Dutkiewicz et al., 2006), Transvaal Supergroup (2.5 Gyr) (Waldbauer et al., 2009), and Archaean rocks from the Pilbara Craton (~2.7 Gyr) (e.gBrocks et al., 1999; Eigenbrode et al., 2008) are likely biased due to contamination (French et al., 2015) and not shown here.”
BackgroundInfluentialMission to Planet Earth: The First Two Billion Years
Stüeken, E. E., Som, S. M., Claire, M. W., Rugheimer, S., Scherf, M., Sproß, L., Tosi, N., Ueno, Y., & Lammer, H. (2020) · Space Science Reviews · doi:10.1007/s11214-020-00652-3 · Cited by 39
Intracellular bound chlorophyll residues identify 1 Gyr-old fossils as eukaryotic algae
Sforna, M.-C., Loron, C., Demoulin, C., François, C., Cornet, Y., Lara, Y. J., Grolimund, D., Sánchez, D. F., Medjoubi, K., Somogyi, A., et al. (2022) · Nature Communications · doi:10.1038/s41467-021-27810-7 · Cited by 39
Self-citationPicard, A., Obst, M., Schmid, G., Zeitvogel, F., & Kappler, A. A. (2015) · Geobiology · doi:10.1111/gbi.12171 · Cited by 40
“7 GPa, as found in the Archean sedimentary record characterized so far, might be already too high to preserve organic biomarkers, such as steranes or hopanes (French et al., 2015).”
BackgroundBekaert, D. V., Broadley, M. W., Delarue, F., Avice, G., Robert, F., & Marty, B. M. (2018) · Science Advances · doi:10.1126/sciadv.aar2091 · Cited by 38
The Taphonomy of Proterozoic Microbial Mats and Implications for Early Diagenetic Silicification
Manning‐Berg, A., Wood, R. S., Williford, K. H., Czaja, A. D., & Kah, L. C. (2019) · Geosciences · doi:10.3390/geosciences9010040 · Cited by 37
“Such understanding is particularly important in light of efforts to develop unique chemical markers, such as the presence of molecular biomarkers [30], the microanalytical identification of carbon sources (cf.”
BackgroundEroglu, S., van Zuilen, M. A., Taubald, H., Drost, K., Wille, M., Swanner, E. D., Beukes, N. J., & Schoenberg, R. (2017) · Precambrian Research · doi:10.1016/j.precamres.2017.09.018 · Cited by 39
Volcanically modulated pyrite burial and ocean–atmosphere oxidation
Olson, S. L., Ostrander, C. M., Gregory, D. D., Roy, M., Anbar, A. D., & Lyons, T. W. (2018) · Earth and Planetary Science Letters · doi:10.1016/j.epsl.2018.11.015 · Cited by 34
Evolution of Aquatic Photoautotrophs
Raven, J. A. (2022) · doi:10.1002/9781119986782.ch2 · Cited by 36
From hopanoids to cholesterol: Molecular clocks of pentameric ligand-gated ion channels
Barrantes, F. J., & Fantini, J. (2016) · Progress in Lipid Research · doi:10.1016/j.plipres.2016.03.003 · Cited by 35
“25 presence of C27-C30 steranes in 2,700 million-year-old Australian rocks was initially suggested to mark the emergence of eukaryotic cells on Earth [143], but this dating has been recently challenged due to probable surface contamination of Archean rocks by hydrocarbon biomarkers [144].”
BackgroundReinhardt, M., Goetz, W., Duda, J., Heim, C., Joachim Reitner, A., & Thiel, V. (2019) · Biogeosciences · doi:10.5194/bg-16-2443-2019 · Cited by 38
“All studied organic-matterbearing Archean rocks were generally subjected to significant thermal overprint that may have completely obliterated indigenous molecular biosignatures (cf., French et al., 2015).”
BackgroundThe Evolution of Cholesterol-Rich Membrane in Oxygen Adaption: The Respiratory System as a Model
Zuniga-Hertz, J. P., & Patel, H. H. (2019) · Frontiers in Physiology · doi:10.3389/fphys.2019.01340 · Cited by 32
Maldanis, L., Hickman‐Lewis, K., Verezhak, M., Guériau, P., Guizar‐Sicairos, M., Jaqueto, P., Trindade, R. I. F., ROSSI, A. L., Berenguer, F., Westall, F., et al. (2020) · Scientific Reports · doi:10.1038/s41598-020-65176-w · Cited by 32
The Organic Isotopologue Frontier
Gilbert, A. R. (2021) · Annual Review of Earth and Planetary Sciences · doi:10.1146/annurev-earth-071420-053134 · Cited by 32
Metadata
- Authors
- French, K. L., Hallmann, C., Hope, J. M., Schoon, P. L., Zumberge, J. A., Hoshino, Y., Peters, C. A., George, S. C., Love, G. D., Brocks, J. J., Buick, R., & Summons, R. E.
- Affiliations
- Massachusetts Institute of Technology (US)
- Max Planck Society (DE)
- Australian National University (AU)
- University of California, Riverside (US)
- Macquarie University (AU)
- University of Washington (US)
- ORCID
- Venue
- Proceedings of the National Academy of Sciences
- Publisher
- National Academy of Sciences
- Published
- 2015-04-27
- Volume
- 112
- Issue
- 19
- Pages
- 5915-5920
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- PMC
- PMC4434754
- OpenAlex
- W1970132751
- Semantic Scholar
- 0236935f5104a4938fd43e23d9b4f55fa2cefd08
- Cited by
- 307
- References
- 43
- Citations by year
- 2026: 13 · 2025: 23 · 2024: 21 · 2023: 14 · 2022: 38 · 2021: 26 · 2020: 27 · 2019: 41 · 2018: 41 · 2017: 25 · 2016: 26 · 2015: 11
- FWCI
- 25.95
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Proceedings of the National Academy of Sciences (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- eScholarship (California Digital Library) (submittedVersion)
- eSpace (Curtin University) (submittedVersion)
- ANU Open Research (Australian National University) (submittedVersion)
- Funders
- Agouron Institute (private foundation, no grant number)
- NSF FESD (1338810)
- NSF GRFP (DGE-1122374)
- Topics
- Physical Sciences › Earth and Planetary Sciences › Paleontology › Paleontology and Stratigraphy of Fossils
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Origins and Evolution of Life
- Physical Sciences › Earth and Planetary Sciences › Geochemistry and Petrology › Geological and Geochemical Analysis
- Keywords
- Archean rocks, hopanes, steranes, hydrocarbon biomarkers, polycyclic aromatic hydrocarbons, diamondoids, eukaryotic origin, Pilbara Craton, thermal maturity
- MeSH terms
- Cyanobacteria, Archaea, Australia, Fossils, Hydrocarbons, Oxygen, Paleontology, Photosynthesis, Polycyclic Aromatic Hydrocarbons, Solvents, Temperature, Biomarkers, Geologic Sediments
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
A language model drew the claims from the paper on 2026-10-08, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-10-08 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
Cited sources are checked with a language model’s help (gpt-6-sol).
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
