Article
Multidisciplinary Sciences
Tom C. L. Bridge, Andrew H. Baird, John M. Pandolfi, Michael J. McWilliam, Mikolaj K. Zapalski
Summary: This study examines the changes in functional diversity of tabulate coral assemblages over a 35 million year period and the impact of the late Devonian extinction event. The collapse of the huge Devonian reef systems resulted in the extinction of photosymbiotic tabulate coral taxa and had long-lasting consequences for reef building and shallow marine ecosystems in the Palaeozoic.
SCIENTIFIC REPORTS
(2022)
Article
Geosciences, Multidisciplinary
Joshua Murray, Oliver Jagoutz
Summary: This study provides a framework for understanding the tectonic forces behind Palaeozoic glaciations by analyzing the impact of rock weathering in ophiolites on organic carbon burial. The results indicate that high-surface-area clays formed during weathering play a significant role in Earth's long-term carbon cycle.
Article
Geology
Elisa Laita, Blanca Bauluz, Marcos Aurell, Beatriz Badenas, Alfonso Yuste
Summary: The study of clay/marl-rich levels from the Torrelapaja Formation in NE Spain revealed the paleoclimatic and paleoenvironmental conditions during their formation, with a mineralogical trend showing characteristics of oxisols. The increase in illitic phases and quartz content, along with authigenic smectite presence, suggest a decrease in chemical weathering possibly associated with a shift to colder, drier conditions during the latest Hauterivian-early Barremian.
JOURNAL OF IBERIAN GEOLOGY
(2022)
Article
Geology
Aitor Payros, Victoriano Pujalte, Birger Schmitz
Summary: By analyzing sediments from the mid-latitude region of Spain, researchers have drawn conclusions about the climate changes during different stages of the ancient hyperthermal event. Comparing with existing models and climate data, the researchers have found that the onset phase of this ancient event may have experienced intense rainfall, while the core phase may have had dry summers and infrequent precipitation. The presence of gypsum in the sediments indicates a drier climate during the recovery phase.
SEDIMENTARY GEOLOGY
(2022)
Article
Multidisciplinary Sciences
Selina R. Cole, Melanie J. Hopkins
Summary: The study found no evidence for extinction selectivity in two mass extinctions of diplobathrid crinoids, but disparity remains strongly correlated with richness over extinction events, contradicting expected patterns of disparity given nonselective extinction.
Article
Geosciences, Multidisciplinary
Martin Meier, Marcio Rocha Francelino, Arthur Stefanelli Gasparini, Andre Thomazini, Antonio Batista Pereira, Fernando Leopoldo von Kruger, Elpidio Inacio Fernandes-Filho, Carlos Ernesto Goncalves Reynauld Schaefer
Summary: Considering the significant influence of Antarctica's extreme climate variation on soil properties and distribution, it is strategically important to characterize and map surface landforms in ice-free areas. The focus of this study was on evaluating the formation processes, classifying, and mapping different soil types in Stansbury Peninsula, Nelson Island. A geosystems' approach was used to stratify the entire environment of the peninsula by identifying the geoenvironmental landscape unit. Geoenvironments and soils were mapped, and their physical-chemical and mineralogical characteristics were analyzed. The results show that Stansbury Peninsula has a thin active layer, making it highly susceptible to climate change and an important monitoring site for climate studies. The northwestern area of the peninsula is a preferred location for marine bird and mammal nesting and resting, resulting in nutrient-rich soils. The harsh climate of Stansbury, characterized by strong northwest polar winds, promotes widespread wind erosion and physical weathering, leading to periglacial processes under wet conditions, typical of the South Shetlands areas exposed to the Drake Passage. The soils in Stansbury are predominantly skeletal, gravelly, with limited organic matter and fauna activity, sparse vegetation cover, and low weathering of volcanic rocks based on high levels of base saturation. They display distinctive physical weathering characteristics due to freezing and thawing processes, resulting in patterned ground (Cryosols) under active periglacial processes. The unique proglacial and peri-glacial geoenvironments of Stansbury are influenced by melting water and widespread snow banks under a wet polar oceanic climate condition.
Article
Geosciences, Multidisciplinary
Mark Baum, Minmin Fu, Stephen Bourguet
Summary: This study found that the long-term variability of global climate is influenced by the size and shape of continents, while the distribution of continents does not explain climate changes well. Runoff patterns are complex, sensitive to detailed features of continental geometry.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Rongxing Li, Yuan Cheng, Tian Chang, David E. Gwyther, Martin Forbes, Lu An, Menglian Xia, Xiaohan Yuan, Gang Qiao, Xiaohua Tong, Wenkai Ye
Summary: Wilkes Land and Totten Glacier in East Antarctica have been experiencing significant ice loss since 1989. However, previous studies have not provided long-term data on ice mass balance, which hinders accurate estimation of its contribution to global sea level rise. In this study, we analyze satellite images from the 1960s to reconstruct ice flow and dynamics in Totten Glacier. Our findings reveal a consistent ice discharge rate and acceleration, indicating that Totten Glacier is the largest contributor to sea level rise in East Antarctica. We attribute this long-term acceleration to basal melting caused by warm modified Circumpolar Deep Water. The study highlights the need for intensified monitoring in the region to better understand and predict future changes.
NATURE COMMUNICATIONS
(2023)
Review
Geography, Physical
Anna S. von der Heydt, Peter Ashwin, Charles D. Camp, Michel Crucifix, Henk A. Dijkstra, Peter Ditlevsen, Timothy M. Lenton
Summary: The spectral view provides a useful tool for understanding climate variability and suggesting causal links between forcing variability and climate response variability. Despite the substantial intrinsic variability in the Earth system, it is possible to provide a better interpretation of climate variability through new observations and methodological developments.
GLOBAL AND PLANETARY CHANGE
(2021)
Article
Multidisciplinary Sciences
Theodore Green, Paul R. Renne, C. Brenhin Keller
Summary: This study investigates the correlation between large igneous provinces (LIPs) and Phanerozoic faunal turnover, and examines the likelihood of such correlations occurring by chance. The results suggest a causal relationship between continental LIPs and extinctions, with a stronger correlation for LIPs with higher eruptive rates and stage boundaries with higher extinction magnitudes. The study also identifies LIP magma degassing as a primary kill mechanism for mass extinctions and intervals of faunal turnover.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Geography, Physical
RachelP. Oien, Iestyn D. Barr, Matteo Spagnolo, Robert G. Bingham, Brice R. Rea, John Jansen
Summary: By mapping and analyzing the distribution and altitude variations of cirques in the Scandinavian Peninsula, the study suggests that cirque floor altitude (CFA) may serve as a proxy for paleoclimate. The results reveal close relationships between CFA and factors such as latitude, aspect, and distance to the coastline, indicating potential links to ancient climate conditions.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Multidisciplinary Sciences
Jennifer F. Arthur, Chris R. Stokes, Stewart S. R. Jamieson, J. Rachel Carr, Amber A. Leeson, Vincent Verjans
Summary: Observations of Antarctic supraglacial lakes (SGLs) are relatively scarce and their interannual variability is largely unknown. This study provides the first observations of SGLs across the entire East Antarctic Ice Sheet over multiple melt seasons. The results show that SGL volume varies greatly from year to year on some ice shelves, with more extensive and deeper lakes associated with higher summer air temperatures. Model predictions suggest that January melt and the ratio of November firn air content to summer melt are important predictors of SGL volume on vulnerable ice shelves.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
N. R. Golledge, P. U. Clark, F. He, A. Dutton, C. S. M. Turney, C. J. Fogwill, T. R. Naish, R. H. Levy, R. M. McKay, D. P. Lowry, N. A. N. Bertler, G. B. Dunbar, A. E. Carlson
Summary: This study suggests that the Antarctic Ice Sheet contributed 4 meters to global mean sea level by 126 ka BP, primarily from the Amundsen Sea sector rather than the Ross or Weddell Sea sectors. The research also indicates that while the AIS thinned in the Wilkes Subglacial Basin, it did not retreat, and there is a risk of future collapse in the West Antarctic Ice Sheet even without further environmental changes.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geography, Physical
Madison L. Ghiz, Ryan C. Scott, Andrew M. Vogelmann, Jan T. M. Lenaerts, Matthew Lazzara, Dan Lubin
Summary: This study utilizes reanalysis data and satellite remote sensing to investigate how meteorological conditions affect the surface energy balance in West Antarctica, leading to surface melt detected in satellite imagery. Different mechanisms for inducing surface melt were identified, with case studies providing insights into the specific conditions that cause melt events. Through further analysis and improvement, this research aims to quantify atmospheric stress on the vulnerable Antarctic ice shelves in a warming climate.
Article
Geosciences, Multidisciplinary
Beatrice Ellerhoff, Moritz J. Kirschner, Elisa Ziegler, Max D. Holloway, Louise Sime, Kira Rehfeld
Summary: Natural forcing from solar and volcanic activity has a significant impact on climate variability. The cooling effect caused by strong volcanic eruptions is more pronounced during colder climate conditions. The response of climate to natural forcing is not dependent on the state, but local differences are mainly influenced by sea ice changes. Forced simulations show better agreement with paleoclimate reconstructions compared to unforced scenarios. Considering natural forcing is thus important for model-data comparison and future projections.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Review
Geography, Physical
Nathan D. Sheldon, Selena Y. Smith, Rebekah Stein, Molly Ng
GLOBAL AND PLANETARY CHANGE
(2020)
Article
Biology
Kathryn Rico, Nathan D. Sheldon, Lauren E. Kinsman-Costello
Article
Geosciences, Multidisciplinary
R. M. Dzombak, N. D. Sheldon, D. M. Mohabey, B. Samant
Article
Plant Sciences
Rebekah A. Stein, Nathan D. Sheldon, Selena Y. Smith
Summary: The study tested the impact of various climate factors on plant carbon isotope discrimination and found that climate variables are not the main driver of carbon isotope discrimination. It was discovered that the discrimination is intrinsic to each taxon and can quantitatively link phylogenetic relationships and adaptation to climate.
Article
Geosciences, Multidisciplinary
Rebekah A. Stein, Nathan D. Sheldon, Selena Y. Smith
Summary: This study explores the relationship between stable carbon isotope values in soil organic matter and climate parameters in modern ecosystems, proposing a potential new paleoprecipitation proxy that can be applied from the Devonian period to the Miocene period. It provides a promising method for extending paleoprecipitation reconstruction in geological records and is calibrated for wetter environments.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Biology
Maya L. Gomes, Judith M. Klatt, Gregory J. Dick, Sharon L. Grim, Kathryn I. Rico, Matthew Medina, Wiebke Ziebis, Lauren Kinsman-Costello, Nathan D. Sheldon, David A. Fike
Summary: The sedimentary pyrite sulfur isotope record serves as an archive of ancient microbial sulfur cycling and environmental conditions. Analysis reveals that porewater sulfide delta S-34 values fluctuate significantly throughout the day due to light-driven changes in microbial activity.
Article
Meteorology & Atmospheric Sciences
Rebekah A. Stein, Nathan D. Sheldon, Selena Y. Smith
Summary: Carbon isotope ecology can be used as a measure of plant water stress, which is influenced by atmospheric-oceanic controls, particularly those related to the Pacific. The study found oscillatory patterns in the carbon isotope discrimination values of Thuja plicata, indicating prolonged stress, while other species did not show clear patterns. These findings provide insight into the impact of Pacific teleconnections on coastal ecosystems and the potential for multiannual climate anomalies.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Review
Geography, Physical
Erik L. Gulbranson, Nathan D. Sheldon, Isabel P. Montanez, Neil J. Tabor, Julia A. McIntosh
Summary: Paleosols provide valuable information about ancient landscapes, biotic interactions, and climate. They have played an important role in studying global climate changes and major extinctions, such as the end-Permian extinction. Recent research suggests that the extinctions in the marine and terrestrial realms during the end-Permian extinction were not synchronous, and there may have been no true mass extinction for plant and vertebrate communities on a global scale.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geography, Physical
Rebecca M. Dzombak, Nikolas C. Midttun, Rebekah A. Stein, Nathan D. Sheldon
Summary: Research shows the importance of considering lateral geochemical variability, sampling multiple paleosol profiles, and focusing on relative rather than absolute changes when using paleosols for climate and environmental reconstructions.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Review
Geosciences, Multidisciplinary
Rebecca M. Dzombak, Nathan D. Sheldon
Summary: Although continental weathering intensity has been considered as a key factor influencing biogeochemistry, tectonics, and the carbon cycle over geological history, its quantification remains inadequate. Paleosols, as a direct product of continental weathering, provide unique insights into past weathering intensity but have been underutilized in studying terrestrial weathering patterns over geological time. This study presents the largest terrestrial weathering record to date, encompassing 248 paleosol and weathering profiles spanning three billion years. The analysis of various weathering indices reveals consistent average terrestrial weathering intensity over time, contrary to previous assumptions. The stability of the continental weathering record suggests that it represents the baseline weathering level, with deviations occurring during periods of perturbation. The findings highlight the importance of subaerially-emerged continental areas in controlling erosion flux and nutrient transport to the oceans. Further efforts are needed to build a more comprehensive database of paleosol geochemistry to enable more nuanced analyses of terrestrial weathering over time.
Article
Geography, Physical
Lauren A. Michel, Nathan D. Sheldon, Timothy S. Myers, Neil J. Tabor
Summary: This study critically evaluates the impact of pretreatment methods on the chemical compositions of modern soils and their implications for estimating mean annual precipitation using two commonly employed climofunction indices. The research finds that acid digestion pretreatment significantly depletes calcium oxide and leads to substantial overestimation of precipitation estimates. The extent of overestimation is correlated with the calcium carbonate content of the soil material. This has important implications for the appropriate application of these indices as proxies for paleoprecipitation estimates from paleosol profiles containing carbonates.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Article
Geosciences, Multidisciplinary
Eliana B. Crawford, Brian K. Arbic, Nathan D. Sheldon, Joseph K. Ansong, Patrick G. Timko
Summary: Research suggests that mid-Archean ocean tides were stronger and more frequent than modern tides, potentially impacting marine productivity. These findings indicate the importance of considering ancient tidal forces when studying Precambrian marine ecosystems.
PRECAMBRIAN RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Rebekah A. Stein, Nathan D. Sheldon, Sarah E. Allen, Michael E. Smith, Rebecca M. Dzombak, Brian R. Jicha
Summary: The study of ancient climates from the early Eocene can help understand ecosystem functions under similar conditions. Through research in the Greater Green River Basin of southwestern Wyoming, it was found that sediment mainly originated from the Idaho paleoriver, with stable environmental conditions and variations in sediment facies and organic carbon burial likely controlled by geomorphology and water table. The ecosystem during this period can be characterized as a wet subtropical-like forest.
CLIMATE OF THE PAST
(2021)
Article
Soil Science
Rebecca M. Dzombak, Nathan D. Sheldon
Article
Geology
Michael T. Hren, Nathan Sheldon
DEPOSITIONAL RECORD
(2020)