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.
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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.
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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
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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
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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
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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.
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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.
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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.
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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.
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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”
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- Also stated in: § Results and Discussion · plain
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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.
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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
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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.
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- 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.
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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
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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.
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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
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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.
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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.
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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
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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
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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 > †
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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 > †
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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 > †
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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
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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.
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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 > †
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plain- Asserted: passes — The authors put it forward as true.
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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.
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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.
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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.
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In the paper
“However, all results from all laboratories are consistent with the results described here.”
§ Reappraisal of hydrocarbon biomarkers in Archean rocks > Methods
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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
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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).”
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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.
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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.
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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 > †
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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.
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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
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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
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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 |”
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Items 201–300 of 312
Tools to trace past productivity and ocean nutrients
Farmer, J. R., Fehrenbacher, J. S., Horner, T. J., & Kast, E. R. (2024) · Elsevier eBooks · doi:10.1016/b978-0-323-99762-1.00039-5 · Cited by 7
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“Moreover, assessing the IOM can overcome misinterpretation of Precambrian organic geochemis‐ try due to contamination risks (French et al., 2015).”
BackgroundAharonovich, S., & George, S. C. (2016) · Australian Journal of Earth Sciences · doi:10.1080/08120099.2016.1247750 · Cited by 4
“These values are suggestive of high thermal maturities of the Keepit A, B and D samples; for example, the highly matured Archean samples reported by French et al. (2015) have values in this range.”
BackgroundSelf-citationMethane Carbon Cycling in the Past: Insights from Hydrocarbon and Lipid Biomarkers
Thiel, V. (2018) · Springer eBooks · doi:10.1007/978-3-319-54529-5_6-1 · Cited by 4
Oxygenation of the Earth’s Atmosphere
Catling, D. C. (2015) · Encyclopedia of Astrobiology · doi:10.1007/978-3-662-44185-5_1141 · Cited by 4
Mángano, M. G., & Buatois, L. A. (2020) · Elsevier eBooks · doi:10.1016/b978-0-08-102908-4.00142-9 · Cited by 4
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The Evolutionary History and Modern Diversity of Triterpenoid Cyclases
McShea, H. S., Viens, R. A., Olagunju, B. O., Giner, J., & Welander, P. V. (2025) · Molecular Biology and Evolution · doi:10.1093/molbev/msaf203 · Cited by 3
“…present in the common ancestor of Gracilicutes, one of the major divisions of bacteria (Santana-Molina et al. 2020), the OSC-SHC ancestor is likely quite ancient, although hopanes and steranes do not appear in the fossil record until 1.6 billion years ago (Brocks et al. 2005; French et al. 2015).”
InfluentialSessions, A. L., Magnabosco, C., Barton, H. A., Burkhardt, C., Dworkin, J. P., Freissinet, C., French, K. L., GLAVIN, D. P., Leys, N., Maixner, F., et al. (2025) · Astrobiology · doi:10.1177/15311074251382157 · Cited by 4
“The representation of hydrocarbons was expanded in both Tier 1a and Tier 1b categories because of their importance as organic biosignatures in ancient rocks on Earth and their vulnerability to contamination through pervasive use of petroleum-based products (French et al., 2015).”
Self-citationWere early Archean carbonate factories major carbon sinks on the juvenile Earth?
Xiang, W., Duda, J., Pack, A., van Zuilen, M. A., & Reitner, J. (2024) · Biogeosciences · doi:10.5194/bg-21-5653-2024 · Cited by 5
“49 Ga North Star Basalt (drill core 102 AIDP-1; 21°06’38"S, 119°06’4"E, French et al., 2015), the ~3.”
Li, Y., Xia, J., & Song, Z. (2019) · Fuel · doi:10.1016/j.fuel.2019.01.133 · Cited by 3
Luo, G., 朱, 祥., Wang, S., 张, 世., & 焦, 超. (2022) · SCIENTIA SINICA Terrae · doi:10.1360/sste-2021-0297 · Cited by 3
Acritarch-like Microorganisms from the 1.9 Ga Gunflint Chert, Canada
González-Flores, A. L., Jin, J., Osinski, G. R., & Tsujita, C. J. (2022) · Astrobiology · doi:10.1089/ast.2021.0081 · Cited by 4
“…eukaryotic biomarkers have been reported from Neoarchean drill-core rocks as old as 2.7 Ga, but subsequent study has provided strong evidence for their origin to be a consequence of contamination from drilling (Brocks et al., 1999; Rasmussen et al., 2008; French et al., 2015; Dacks et al., 2016).”
InfluentialWang, D., Schwark, L., Ruebsam, W., Holman, A. I., Böttcher, M. E., Idiz, E., Coolen, M. J. L., & Grice, K. (2022) · Earth and Planetary Science Letters · doi:10.1016/j.epsl.2022.117857 · Cited by 5
Assessing biomarker syngeneity: An in situ approach using monoclonal antibodies
Ferrer, F. M., Bailey, J. V., Corsetti, F. A., Moldowan, J. M., Barbanti, S. M., Caron, D. A., & Bryant-Huppert, J. (2018) · Organic Geochemistry · doi:10.1016/j.orggeochem.2018.05.006 · Cited by 3
Cambrian trilobites as archives for Anthropocene biomarkers and other chemical compounds
John, D. L., Medeiros, P. M., Babcock‐Adams, L., & Walker, S. E. (2017) · Anthropocene · doi:10.1016/j.ancene.2017.03.002 · Cited by 3
Hallberg, R. O., & Broman, C. (2017) · Geomicrobiology Journal · doi:10.1080/01490451.2017.1348407 · Cited by 3
“Though indications of microbial activity have been proposed based on the organic chemistry (French et al. 2015), they con-”
BackgroundInfluentialA molecular window to the primeval world
Xiaopeng, W., & Yuan, X. (2019) · Chinese Science Bulletin (Chinese Version) · doi:10.1360/n972019-00304 · Cited by 2
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“…control, and pyrolysis ( e.g. , flash and laser micropyrolysis), and spectroscopy techniques over the last decade that permit extraction and fine-scale characterization of the structure and composition of relic biomarkers, thus identify or limit secondary contamination (French et al. , 2015).”
Self-citationBhattacharya, S., Dutta, S., & Kumar, S. (2021) · Geobios · doi:10.1016/j.geobios.2021.04.003 · Cited by 3
Zumberge, J. A. (2019) · eScholarship (California Digital Library) · Cited by 3
Self-citationSterol methyltransferases in annelid worms rewrite the molecular fossil recordPreprint
Gold, D. A., Brunoir, T. N., Mulligan, C., Sistiaga, A., Vuu, K. M., Shih, P. M., O’Reilly, S. S., & Summons, R. E. (2022) · Research Square · doi:10.21203/rs.3.rs-1686449/v1 · Cited by 3
Self-citationUnique C‐Ring Methylated Hopene Biomarkers in a Paleocene Lake
Naafs, B. D. A. (2025) · Paleoceanography and Paleoclimatology · doi:10.1029/2024pa004977 · Cited by 2
“The resulting hopanes (Figure 1) are among the most abundant fossil lipids on Earth (Dorsselaer et al., 1974; Ourisson & Rohmer, 1992) and can be preserved in the rock record for more than one billion years (Brocks et al., 2005; French et al., 2015).”
Quality Control Measures for Enhancing Confidence in Nanoscale IR Spectroscopy
Förster, M. W., Otter, L. M., Brocks, J. J., Jayasoma, K., Cisneros‐Lazaro, D., Nowak, D. B., Stolarski, J., & Knowles, B. M. (2025) · Geostandards and Geoanalytical Research · doi:10.1111/ggr.70014 · Cited by 2
Self-citationLiu, Q., Xu, H., Wang, J., Zhu, D., Zhang, C., Zhu, B., Fu, Y., Zhang, W., Li, J. R., Zhu, D., et al. (2026) · Nature Communications · doi:10.1038/s41467-026-68745-1 · Cited by 2
“To ensure the indigeneity of hydrocarbons extracted from chimneys, all preparation steps were carefully monitored for potential contamination, including solvents, glassware, evaporation systems, cutting tools, samplehandling materials, etc 67 – 69 .”
Teece, B. L., Brock, G., Paterson, J., Skovsted, C., Holmer, L., & George, S. (2021) · Journal of Analytical and Applied Pyrolysis · doi:10.1016/j.jaap.2021.105277 · Cited by 2
“Furthermore, when these methods are applied to organically-lean samples, the potential risks of contamination are high, but can be somewhat mitigated when stringent controls such as slice experiments and blanks are utilized [5-7].”
MethodSelf-citationGorozhanin, V. M. (2023) · Geologicheskii vestnik · doi:10.31084/2619-0087/2023-1-2 · Cited by 2
“Фракционированные экстракты анализировали методом газовой хроматографии и масс-спектрометрии (GC-MS) по ме- тодике, описанной в [Leider et al. 2016] (полное сканирование всего спектра) и [French et al. 2015].”
Dawson, R. R., Castañeda, I. S., Burns, S. J., et al. (2024) · Organic Geochemistry · doi:10.1016/j.orggeochem.2024.104810 · Cited by 2
Discriminating between extinct and extant life detection: implications for future Mars missions
Dzurilla, K. A., & Teece, B. L. (2024) · Frontiers in Astronomy and Space Sciences · doi:10.3389/fspas.2024.1452362 · Cited by 2
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Atmospheric oxygen and methane on the early Earth
Kasting, J. F., & Ji, A. (2025) · Philosophical Transactions of the Royal Society B Biological Sciences · doi:10.1098/rstb.2024.0093 · Cited by 3
“Putative biomarker evidence for O 2 production at 2.7 Ga [56,57] has now been discredited [58].”
InfluentialHistory of Life from the Hydrocarbon Fossil Record
Walters, C. C., Peters, K. E., & Moldowan, J. M. (2020) · Springer eBooks · doi:10.1007/978-3-319-90569-3_32 · Cited by 3
王, 铜., 赵, 文., 王, 晓., 任, 荣., 管, 树., 叶, 云., 王, 华., 张, 水., & 胡, 素. (2018) · SCIENTIA SINICA Terrae · doi:10.1360/n072018-00158 · Cited by 1
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PRESERVAÇÃO DE GEOPOLÍMEROS NO REGISTRO ESTRATIGRÁFICO E SUAS IMPLICAÇÕES PALEOAMBIENTAIS
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Sample Science Traceability Matrix for Perseverance ’s Mars Sample Return Collection
Zorzano, M., Czaja, A. D., Bosak, T., Bouvier, A., Carrier, B. L., French, K. L., GLAVIN, D. P., Harrington, A. D., Hausrath, E. M., Herd, C. D. K., et al. (2025) · Astrobiology · doi:10.1177/15311074251382585 · Cited by 1
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InfluentialSelf-citationOrigins of Archean organic matter
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Radiolytic CH4 and CO2 from irradiated organic compounds
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Moving to the Light: The Evolution of Photosynthesis
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Ocean redox evolution past and present
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Microalgae as Sustainable and Economic Sources of Omega-3 Fatty Acids
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History of Life from the Hydrocarbon Fossil Record
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“…presented above is consistent with the bulk of the available geochemical and biochemical data from the era (Kasting, 1993; Lowe and Tice, 2004; French et al., 2015; Meixnerová et al., 2021) and, most importantly, consistent with the very particular and finely tuned UV-C photochemical…”
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Reassessing the Syngeneity of Biomarkers from South China: Late Neoproterozoic or Not?
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“However, contamination of geological samples with anthropogenic petroleum products during drilling, storage and sampling can be particularly problematic when studying organic-lean Precambrian samples, because these contaminants may over-print the original indigenous biomarker profile, potentially resulting in misleadi…”
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“The only detected organic compounds in Bitumen I are highly mature n-alkanes, diamondoids and aromatic hydrocarbons (French et al., 2015).”
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Early Life from the Proterozoic Sedimentary Basins of India
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Martins, E. G., Cavalcante, D. D. C., da Silva, D. B. I. N., & Pereira, E. (2022) · doi:10.22533/at.ed.1582206016
DISTRIBUIÇÃO ESPACIAL DOS INTERVALOS OIL SHALE PERMIANOS DA BACIA DO PARANÁ
Brito, A. D. S., de Almeida, L. T. G., & de Lima, S. G. (2022) · doi:10.22533/at.ed.1582206019
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Silva, A. F., Barros, A. L. D. C., Marsaioli, A. J., & de Lima, S. G. (2022) · doi:10.22533/at.ed.1582206011
COMPOSTOS POLARES EM PETRÓLEO APLICADOS A PROCESSOS GEOCROMATOGRÁFICOS
Miranda, P. C. M. L., Maior, C. R. S., de Lima, S. G., & Sousa, G. R. (2022) · doi:10.22533/at.ed.1582206018
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ANÁLISE DE BIOMARCADORES NEUTROS EM SEDIMENTO DA FORMAÇÃO SERRA ALTA - PERMIANO (BACIA DO PARANÁ)
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Summons, R. E. (2018) · Encyclopedia of earth sciences series/Encyclopedia of earth sciences · doi:10.1007/978-3-319-39312-4_191 · Cited by 1
Self-citationFossilized eukaryotes from 2.7 billion year old shales in TanzaniaPreprint
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Oxygenation of the Earth’s Atmosphere
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Characterization and Developmental Background of Global Precambrian Hydrocarbon Source Beds
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STEROL METHYLTRANSFERASES IN ANNELID WORMS REWRITE THE MOLECULAR FOSSIL RECORD
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Proterozoic excluding basal ∼2500–2350 ma Paleoproterozoic and ∼635–541 ma Vendian
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“…in the common ancestor of Gracilicutes, one of the major divisions of bacteria (Santana-Molina et al., 2020), the OSC-SHC ancestor is likely quite ancient, although hopanes and steranes do not appear in the fossil record until 1.6 billion years ago (Brocks et al., 2005; French et al., 2015).”
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Evidence of Earth's early biosphere from the Pilbara region, Western Australia
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“The syngenetic origin of organic material cracking below 350 °C is highly disputable since it can originate from several post-deposition contaminations and/ or from residual bitumen (soluble fraction of organic matter) for which syngenecity is still an open issue (French et al., 2015).”
BackgroundMicro et nanoanalyses des microfossiles du Protérozoïque et de tapis microbiens fossiles
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“Cependant, il a été par la suite montré que ces biomarqueurs résultaient d’une contamination (Brocks et al., 2008; French et al., 2015; Rasmussen et al., 2008).”
Background
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 ›
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