Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath

May combine two claims.

An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes, where glacial-interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene.

“An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial-interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene.”

• cites Ávila and Dávila, 2018 sourcePartly supported

  Split into 2 atoms — 0 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 1 unverifiable. Expand the claim to see per-atom verdicts.

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Previous GIA studies infer a low asthenosphere viscosity (in the order of 10^18 Pa s) and a thin elastic lithosphere (∼35 km thick) to match the very high observed uplift rate budget.

“To match the very high observed uplift rate budget, previous GIA studies infer a low asthenosphere viscosity (in the order of 10 18 Pa s) and a thin elastic lithosphere (∼ 35 km thick) (Ivins andJames, 1999, 2004;Klemann et al., 2007;Dietrich et al., 2010;Lange et al., 2014;Richter et al., 2016;Ávila and Dávila, 2020;Mark et al., 2022;Lenzano et al., 2023).”

• cites Ivins and James, 1999 sourcePartly supported

  Figure 11 (section 6.4.1; page not supplied) models Patagonian uplift with a 35 km lithosphere and mantle viscosities of 1–2 × 10^19 Pa s; Figure 13 considers a viscosity reduced by half. These are predicted responses, not parameters inferred by matching a very high observed uplift rate. The paper describes the motion as potentially geodetically detectable rather than reporting such an observational fit. (LLM, conf=0.88)

  Experimental — accuracy not yet measured
• cites Klemann et al., 2007 sourceNot checked — no full text of the source
• cites Dietrich et al., 2010Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

Classified as probably not a substantial claim.

The contribution of post-LGM deglaciation to present-day rock uplift rate was marginally addressed.

“In addition, the contribution of post-LGM deglaciation to present-day rock uplift rate was marginally addressed (Ivins andJames, 1999, 2004;Klemann et al., 2007).”

• cites Ivins and James, 1999 sourceSupported
• cites Klemann et al., 2007 sourceNot checked — no full text of the source

May combine two claims.

The rheologic and thermal structure of the reference model gives a lithospheric elastic thickness, Te, of ∼30 km, comparable to previous estimates underneath the SPI.

“The rheologic and thermal structure of the reference model gives a lithospheric elastic thickness, T e (sensu Burov and Diament, 1995), of ∼ 30 km, comparable to previous estimates underneath the SPI based on GIA models (Ivins and James, 1999;Dietrich et al., 2010;Lange et al., 2014), heat flow data (Ávila and Dávila, 2018), waveform inversion (Robertson Maurice et al., 2003), and low-temperature”

• cites Ivins and James, 1999 sourceSupported
• cites Dietrich et al., 2010Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Lange et al., 2014 sourceNot checked — no full text of the source

May combine two claims.

Low-temperature thermochronology studies suggest using erosion values between 0.1 and 1 mm yr-1 from 7 to 4 Ma, followed by a period of erosional quiescence (<0.1 mm yr-1) and a possible increase to 1 mm yr-1 in the last ∼2 Myr in the SPI region.

“Fosdick et al. (2013), Herman and Brandon (2015), Fernandez et al. (2016), andMuller et al. (2023) suggest using values between 0.1 and 1 mm yr -1 from 7 to 4 Ma, followed by a period of erosional quiescence (< 0.1 mm yr -1 ) and a possible increase to 1 mm yr -1 in the last ∼ 2 Myr in the SPI region”

• cites Fosdick et al., 2013Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Herman and Brandon, 2015 sourceNot checked — no full text of the source
• cites Muller et al., 2023 sourcePartly supported

  The Conclusions (page unavailable) describe rapid exhumation at Fitz Roy and Torres del Paine between 7 and 4 Ma, subsequent erosional quiescence, and a partly recorded Quaternary acceleration. Section 5.2 (page unavailable) reports 7–4 Ma exhumation rates of 0.6–3 km/Myr (equivalent to mm/yr), not a uniform 0.1–1 mm/yr range; it gives no <0.1 mm/yr rate for the quieter period. It reports ~1 mm/yr Quaternary exhumation in parts of Torres del Paine, with onset varying from 3 to 0.5 Ma, rather than establishing that rate throughout the SPI region over the last ~2 Myr. (LLM, conf=0.88)

  Experimental — accuracy not yet measured

Classified as probably not a substantial claim.

Given the geologically short time window investigated here, deformation related to longer-term tectonic forces is neglected.

“Given the geologically short time window investigated here, we neglect deformation related to longer-term tectonic forces (Breitsprecher and Thorkelson, 2009;Guillaume et al., 2013;Eagles and Scott, 2014;Muller et al., 2021).”

• cites Breitsprecher and Thorkelson, 2009Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Guillaume et al., 2013 sourceNot checked — no full text of the source
• cites Eagles and Scott, 2014 sourceSupported

May combine two claims.

The asthenosphere viscosity from the models when TA > 100 °C is <10^19 Pa s, with the lowest viscosity value of 10^16 Pa s imposed where partial melting occurs.

“the asthenosphere viscosity from our models when TA > 100 °C is < 10 19 Pa s, with the lowest viscosity value of 10 16 Pa s imposed where partial melting, supported by the regional Holocene volcanism (Stern and Kilian, 1996) and by geophysical data (e.g.shear wave velocity data by Mark et al., 2022), occurs.”

• cites Stern and Kilian, 1996 sourceNot checked — no full text of the source
• cites Mark et al., 2022 sourcePartly supported

  Section 3.1 reports anomalously low shear-wave velocities in the Patagonian slab window, so Mark et al. provide the geophysical data cited. Section 3.2 says thermal erosion likely requires melt or fluids and that melt may be supplied by upwelling mantle; it does not establish that partial melting occurs at the specific locations where the citing authors impose their lowest viscosity. The viscosity values are attributed to the citing authors’ own models, not to Mark et al. (LLM, conf=0.84)

  Experimental — accuracy not yet measured

May combine two claims.

In the post-LIA model set, the maximum uplift rate reaches ∼8.3 and ∼23 mm yr-1 during the first 100 years of deglaciation when TA is respectively 150 and 200 °C.

“whereas it reaches ∼ 8.3 and ∼ 23 mm yr -1 during the same interval when TA is respectively 150 and 200 °C”

May combine two claims.

The asthenosphere viscosity ranges between 10^22-10^19 Pa s in simulations with TA equal to 0, 50, and 100 °C and between 10^19-10^16 Pa s in simulations with TA equal to 150 and 200 °C.

“The asthenosphere viscosity ranges between 10 22 -10 19 Pa s in simulations with TA equal to 0 (reference model), 50, and 100 °C and between 10 19 -10 16 Pa s in simulations with TA equal to 150 and 200 °C (Fig. 3a-d).”

May combine two claims.

This results in predominant elastic deformation in the upper crust (below the ∼300 °C isotherm) and upper mantle lithosphere (below the ∼700 °C isotherm) and viscous deformation in the lower crust and lower lithospheric mantle and asthenosphere.

“This results in predominant elastic deformation in the upper crust (below the ∼ 300 °C isotherm) and upper mantle lithosphere (below the ∼ 700 °C isotherm) and viscous deformation in the lower crust and lower lithospheric mantle and asthenosphere”

May combine two claims.

After the end of the deglaciation, the maximum uplift rate takes longer than about 5000 years to re-equilibrate to 0 mm yr−1 when TA ≤ 100 °C, whereas it drops to 0 mm yr−1 almost immediately when TA is 150 or 200 °C.

“After the end of the deglaciation, the maximum uplift rate takes longer than about 5000 years to re-equilibrate to 0 mm yr -1 when TA ≤ 100 °C, whereas it drops to 0 mm yr -1 almost immediately when TA is 150 or 200 °C (Fig. 7a).”

May combine two claims.

In Model set 1 for post-LGM deglaciation, when TA equals 0 (reference model) the maximum uplift rate is <1 mm yr−1 during the first 5000 years of the deglaciation, increasing gradually up to 9.5 mm yr−1 in the later stages of the deglaciation (i.e. 20 000 years).

“In Model set 1 for post-LGM deglaciation, when TA equals 0 (reference model) the maximum uplift rate is < 1 mm yr -1 during the first 5000 years of the deglaciation, increasing gradually up to 9.5 mm yr -1 in the later stages of the deglaciation (i.e.20 000 years, Fig. 4).”

May combine two claims.

Lithospheric warming due to increasing asthenospheric mantle potential temperature leads to a reduction in the lower lithosphere viscosity (from 10^22 to 10^20 Pa s), thereby decreasing the integrated lithospheric strength.

“Lithospheric warming due to increasing asthenospheric mantle potential temperature also leads to a reduction in the lower lithosphere viscosity (from 10 22 to 10 20 Pa s), thereby decreasing the integrated lithospheric strength.”

May combine two claims.

In the post-LIA model set, the maximum uplift rate is ∼1.4, ∼2.3, and ∼2.2 mm yr-1 during the first 100 years of deglaciation when TA is respectively 0, 50, and 100 °C.

“In the post-LIA model set, the maximum uplift rate is ∼ 1.4, ∼ 2.3, and ∼ 2.2 mm yr -1 during the first 100 years of deglaciation when TA is respectively 0, 50, and 100 °C”

May combine two claims.

When TA equals 50, 100, 150, and 200 °C, the maximum uplift rates can reach up to ∼2, ∼5, ∼12, and ∼15 mm yr−1, respectively, already in the first 1000 years of the deglaciation.

“When TA equals 50, 100, 150, and 200 °C, the maximum uplift rates can reach up to ∼ 2, ∼ 5, ∼ 12, and ∼ 15 mm yr -1 , respectively, already in the first 1000 years of the deglaciation (Fig. 4a).”

May combine two claims.

When higher temperatures are imposed in the asthenospheric mantle, shallower 300 and 700 °C isotherms decrease Te and increase the isostatic surface uplift rates.

“when we impose higher temperatures in the asthenospheric mantle, shallower 300 and 700 °C isotherms decreases T e and increases the isostatic surface uplift rates.”

The quote only partly states this claim.

The modelled maximum post-glacial rebound matches the observed uplift rate budget only if a standard continental asthenospheric mantle potential temperature is increased by 150-200 °C.

“post-LIA and post-LGM deglaciation are accounted for and only if a standard continental asthenospheric mantle potential temperature is increased by 150-200 °C.”

May combine two claims.

The deglaciation triggers uplift in the region covered by the melting pseudo-ice cap and subsidence in the neighbouring regions.

“In agreement with the theory of lithospheric flexure (e.g.Turcotte and Schubert, 2002), the deglaciation triggers uplift in the region covered by the melting pseudo-ice cap and subsidence in the neighbouring regions (Figs.456).”

• cites Turcotte and Schubert, 2002 sourceNot checked — no full text of the source

May combine two claims.

The elastic thickness of the lithosphere (Te) varies between the simulations according to the imposed asthenospheric thermal anomaly, but it is generally lower than 30 km, resulting in a decoupled lithospheric rheology.

“The elastic thickness of the lithosphere (T e ) varies between the simulations according to the imposed asthenospheric thermal anomaly, but it is generally lower than 30 km, resulting in a decoupled lithospheric rheology”

• cites Burov and Diament, 1995 sourceNot checked — no full text of the source

May combine two claims. The quote only partly states this claim.

Experiments that account for a low viscosity asthenosphere and long-term post-LGM deglaciation lasting for 20 000 and 10 000 years reach up to ∼25 and ∼42 mm yr-1 of uplift rate during the final stages of the deglaciation, respectively, comparable to present-day values.

“Experiments that account for a low viscosity asthenosphere and long-term post-LGM deglaciation lasting for 20 000 and 10 000 years reach up to ∼ 25 and ∼ 42 mm yr -1 of an uplift rate during the final stages of the deglaciation”

May combine two claims.

In the faster post-LGM deglaciation scenario (Model set 2), the observed maximum uplift rate budget is attained in about 10 000 years of deglaciation, but only minor residual rebound could be observed today regardless of the amount of ice loss.

“In the faster post-LGM deglaciation scenario (Model set 2) the observed maximum uplift rate budget is attained in about 10 000 years of deglaciation, but only minor residual rebound could be observed today regardless of the amount of ice loss”

May combine two claims.

The Chile triple junction at ∼46° S delimits the surface tip of the asthenospheric window, which opened during the last ∼16 Myr from south to north.

“The Chile triple junction (CTJ) at ∼ 46° S delimits the surface tip of the asthenospheric window, which opened during the last ∼ 16 Myr from south to north (Ramos and Kay, 1992;Breitsprecher and Thorkelson, 2009).”

• cites Ramos and Kay, 1992 sourceNot checked — no full text of the source
• cites Breitsprecher and Thorkelson, 2009Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

May combine two claims.

The Patagonian Ice Sheet covered the southern Patagonian Andes between ∼47 000 and ∼17 000 yr BP, extending from latitudes 38 to 55° S with an estimated area of ∼490 000 km2, volume of ∼550 000 km3, and average and maximum thickness of 1100 and 2500 m.

“The Patagonian Ice Sheet covered the southern Patagonian Andes between ∼ 47 000 and ∼ 17 000 yr BP, extending from latitudes 38 to 55° S with an estimated area of ∼ 490 000 km 2 (Fig. 1a); volume of ∼ 550 000 km 3 ; and average and maximum thickness of 1100 and 2500 m, respectively, based on preserved glacial geomorphology, stratigraphy, palaeoecology, and geochronological data (Moreno et al., 199”

• cites Moreno et al., 1999Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Hulton et al., 2002 sourceNot checked — no full text of the source
• cites Glasser et al., 2004 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

The high uplift rates in the northern part of the SPI are currently ascribed to lithospheric viscoelastic GIA following the LIA, which was responsible for an ice loss of 503 ± 101.1 km3 in the SPI.

“Such outstandingly high uplift rates, especially in the northern part of the SPI, are currently ascribed to the lithospheric viscoelastic GIA following the LIA, which was responsible for an ice loss of 503 ± 101.1 km 3 in the SPI (Glasser et al., 2011).”

• cites Glasser et al., 2011 sourceNot checked — no full text of the source

May combine two claims.

GNSS-measured data show ongoing vertical rock uplift rates between 18 ± 3 and 41 ± 3 mm yr−1 in the northern part (18-50.5°S) of the SPI, decreasing to values between 2 ± 6 and 17 ± 5 mm yr−1 in its southern part (50.5-51.5°S).

“GNSS-measured data show ongoing vertical rock uplift rates between 18 ± 3 and 41 ± 3 mm yr -1 in the northern part (18-50.5°S) of the SPI (Fig. 1b), decreasing to val-ues between 2 ± 6 and 17 ± 5 mm yr -1 in its southern part (50.5-51.5°S) (Ivins and James, 2004;Dietrich et al., 2010;Lange et al., 2014;Richter et al., 2016;Lenzano et al., 2023).”

• cites Ivins and James, 2004 sourceNot checked — no full text of the source
• cites Dietrich et al., 2010Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Lange et al., 2014 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

The forcing of global cooling in increasing erosion rates during the Quaternary is debated, and not widely quantified in Patagonia nor worldwide.

“The forcing of global cooling in increasing erosion rates during the Quaternary is, however, debated, and not widely quantified in Patagonia nor worldwide”

• cites Valla et al., 2012Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Champagnac et al., 2014Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Herman et al., 2013 sourceNot checked — no full text of the source

Classified as probably not a substantial claim.

The simplification of a constant lateral extent of the pseudo-ice cap does not significantly affect the magnitude of post-glacial rebound.

“Although this simplification may affect the inferred pattern of post-glacial rebound, it greatly facilitates the simulation of deglacial lithospheric unloading without significantly affecting the magnitude of post-glacial rebound, which is the main focus here.”

Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

Supposing that these erosion rates still apply in the last ∼20 000 years, this would translate into 2-20 m of rocks eroded on average since the LGM, leading to local unloading of approximately 60-600 kPa if one assumes a crustal density of 3000 kg m-3.

“Supposing that these erosion rates still apply in the last ∼ 20 000 years, this would translate into 2-20 m of rocks eroded on average since the LGM, leading to local unloading of approximately 60-600 kPa if one assumes a crustal density of 3000 kg m -3”

• AssumptionThe authors state this as an assumption: The erosion rates from low-temperature thermochronology still apply in the last ∼20 000 years.
• AssumptionThe authors state this as an assumption: The crustal density is 3000 kg m-3.

Probably not a substantial claim: may not pass S3 (load-bearing).

Previous models have assumed simple deglaciation histories as well.

“As a result, previous models have assumed simple deglaciation histories as well”

• cites Ivins and James, 1999, 2004Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

• cites Hulton et al., 2002 sourceNot checked — no full text of the source
• cites Klemann et al., 2007 sourceNot checked — no full text of the source

May combine two claims.

Overall, notwithstanding these limitations in the model, the fully coupled numerical thermomechanical geodynamic experiments provide realistic uplift rates that one can compare to current geodetic observations.

“Overall, notwithstanding these limitations in the model, our fully coupled numerical thermomechanical geodynamic experiments provide realistic uplift rates (Figs.4567) that one can compare to current geodetic observations.”

May combine two claims.

Such stress change is approximately equivalent to the melting of about 6-60 m of ice, whereas the simulations simulate the melting of 200-1500 m of ice.

“Such stress change is approximately equivalent to the melting of about 6-60 m of ice, whereas we simulate the melting of 200-1500 m of ice in our simulations.”

May combine two claims.

Overall, a warmer and less viscous asthenosphere generates a higher magnitude post-glacial rebound which takes much longer to re-equilibrate to 0 mm yr-1 after the end of the deglaciation than a cooler and more viscous asthenosphere.

“Overall, a warmer and less viscous asthenosphere generates a highermagnitude post-glacial rebound which, however, takes much longer to re-equilibrate to 0 mm yr -1 after the end of the deglaciation than a cooler and more viscous asthenosphere.”

Probably not a substantial claim: may not pass S3 (load-bearing).

GNSS, SRTM, and GRACE data, constraining the net ice mass balance only during the last few decades, still show some discrepancies.

“GNSS, SRTM, and GRACE data, constraining the net ice mass balance only during the last few decades, still showing some discrepancies”

• cites Aniya, 1996 sourceNot checked — no full text of the source
• cites Aniya et al., 1997 sourceNot checked — no full text of the source
• cites Rignot et al., 2003 sourceNot checked — no full text of the source

Probably not a substantial claim: may not pass S3 (load-bearing).

Our modelling is simplistic in that we impose a linear and uniform ice loss instead of a more realistic ice sheet melting pattern in space and time.

“Our modelling is simplistic in that we impose a linear and uniform ice loss instead of a more realistic ice sheet melting pattern in space and time”

May combine two claims.

Asthenospheric thermal anomalies higher than 200 °C are unlikely and would decrease the asthenospheric viscosities to unrealistic values (less than 10^16 Pa s).

“Asthenospheric thermal anomalies higher than 200 °C are unlikely and would decrease the asthenospheric viscosities to unrealistic values (less than 10 16 Pa s).”

May combine two claims.

Using 10^16 < v < 10^18 Pa s and λ = 200 km leads to ∼2000 < τr <∼200 000 years, a time range considerably longer than the post-LIA deglaciation and including full Pleistocene glacial-interglacial cycles.

“Using 10 16 < v < 10 18 Pa s and λ = 200 km leads to ∼ 2000 < τ r <∼ 200 000 years, a time range considerably longer than the post-LIA deglaciation and including full Pleistocene glacial-interglacial cycles”

• cites Turcotte and Schubert, 2002 sourceNot checked — no full text of the source
• cites Ruddiman et al., 1986 sourceNot checked — no full text of the source

May combine two claims.

It appears that post-LIA rebound alone cannot cover the entire budget of the observed uplift rates even with the highest tested TA, which points to a non-negligible contribution from post-LGM deglaciation.

“it appears that post-LIA rebound alone cannot cover the entire budget of the observed uplift rates even with the highest tested TA, which points to a non-negligible contribution from post-LGM deglaciation.”

May combine two claims.

Results indicate that the outstanding observational budget of rock uplift in the SPI is matched only when accounting for higher-than-normal asthenospheric mantle temperatures, thereby highlighting the relevance of the regional asthenospheric window.

“Results, therefore, indicate that the outstanding observational budget of rock uplift in the SPI is matched only when accounting for higher-thannormal asthenospheric mantle temperatures, thereby highlighting the relevance of the regional asthenospheric window.”