Article
Oceanography
Qingmiao Li, Wenshen Xiao, Rujian Wang, Zhihua Chen
Summary: The study found that the environment in the Cosmonaut Sea is mainly influenced by the melting of the West Antarctic Ice Sheet during the Last Glacial Maximum, while the East Antarctic Ice Sheet remained relatively stable. The maximum retreat of sea ice and intrusion of warm Circumpolar Deep Water in the early Holocene facilitated the melting of the East Antarctic Ice Sheet.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2021)
Article
Geology
Yuxin Zhou, Jerry McManus
Summary: This paper investigates in detail a layer of red sediments deposited along the northwestern Atlantic Ocean 125,000 years ago. It finds that this deposit was a glacial outburst event similar to the one that occurred 8,200 years ago. The freshwater discharge associated with this event may explain several global abrupt changes, including a reduction in North Atlantic Deep Water and the resurgence of Antarctic Bottom Water. The study suggests that the mechanism behind this event is a significant part of the deglacial sequence.
Article
Geochemistry & Geophysics
Nisha Bharti, Ravi Bhushan, Luke Skinner, M. Muruganantham, Partha Sarathi Jena, Ankur Dabhi, A. Shivam
Summary: The Indian Ocean, accounting for a significant portion of the global ocean volume, plays an important role in glacial-interglacial carbon cycle dynamics. Analysis of radiocarbon data from marine sediment cores in the Central Indian Ocean reveals significant ocean-atmosphere radiocarbon disequilibrium during the last glaciation. The CIO gradually approached modern values during the Holocene, indicating its distinct behavior in carbon ventilation. These findings highlight the important contribution of the Indian Ocean to deglacial carbon cycle change.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Kumari Nisha, Sushant Suresh Naik, Pankaj Kumar, Barnita Banerjee, P. B. Rama Murty
Summary: This study investigates the ventilation changes in deep waters of the northern Indian Ocean over the past 25 kyr BP, and finds that a greater proportion of CO2-rich Antarctic Bottom Water (AABW) was present during the Last Glacial Maximum (LGM) and Heinrich Stadial (HS1). Poor ventilation during the last glaciation indicates that the northern Indian Ocean was part of the glacial carbon pool, while improved ventilation during the Bolling-Allerod (B-A) suggests the inflow of North Atlantic Deep Water (NADW) caused degassing from the northern Indian Ocean. Overall, this study supports the role of the Southern Ocean in modulating atmospheric CO2 variations during the last deglaciation.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Ekaterina Ovsepyan, Elena Ivanova, Martin Tetard, Lars Max, Ralf Tiedemann
Summary: The study semi-quantitatively estimated the dissolved oxygen concentrations in the western Bering Sea during the deglaciation, revealing distinct changes in oxygen content in intermediate and deep waters during different periods. The variations in oxygen concentrations in the intermediate depths were linked to the North Atlantic climate, while those in the deep waters were associated with changes in the circulation of southern-sourced waters and amplified by Northern Hemisphere climate warming. The region of the Bering Sea and sea-level oscillations significantly contributed to the magnitude of oxygenation changes during the last deglaciation, with more pronounced changes observed in the Bering and Okhotsk marginal seas compared to the open-ocean continental margin and abyssal settings of the North Pacific.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geography, Physical
Louis Rouyer-Denimal, Aline Govin, Ioanna Bouloubassi, Thanh Thuy Nguyen Tu, Ana Luiza Spadano Albuquerque, Christelle Anquetil, Arnaud Huguet
Summary: The role of cross-equatorial currents in the northward spreading of warm and salty waters during glacial terminations is essential. This study presents temperature records based on organic proxies from a marine sediment core covering the last 305 thousand years before present. The results suggest that the strong warming of the tropical western Atlantic during glacial terminations can be explained by the combined influences of the thermal bipolar seesaw and the Agulhas Leakage. Additionally, an enhanced cross-equatorial gyre may explain the synchronous deglacial warming of the western and eastern sides of the tropical Atlantic.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
C. M. Darvill, B. Menounos, B. M. Goehring, A. J. Lesnek
Summary: This study reports 20 Be-10 exposure ages from glacial erratics and bedrock on the west coast of British Columbia, Canada, contributing to the existing chronologies of Cordilleran Ice Sheet retreat along approximately 600 km of coastal North America. The data show that the western ice limit reached the present coast by 18-16 ka then slowed its retreat for around 4,000 years until 14-13 ka. The initial retreat is attributed to destabilization and grounding line retreat caused by rising sea level and/or ocean warming in the northern Pacific. Despite increasing temperatures, the subsequent stability of the ice sheet at the present coastal margin is likely due to the transition from marine to terrestrial margins.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Yechen Sun, Wenshen Xiao, Rujian Wang, Li Wu, Yijing Wu
Summary: Changes in water circulation in the Bering Sea from the last deglaciation to the Holocene have greatly affected biological productivity, the carbon cycle, and global ocean circulation. The study of grain size and clay mineral composition in core ARC6-B10 from the northern Bering slope reveals that sea level rise and atmospheric circulation are the primary controls on these variations. Deglacial sea level rise and changes in atmospheric circulation have deepened water passages, enhanced the flow of North Pacific water, and receded coastlines, influencing the sediment provenance in the Bering Sea.
Article
Geography, Physical
Debarati Nag, Binita Phartiyal, Shailesh Agrawal, Pankaj Kumar, Rajveer Sharma, Kamlesh Kumar, Anupam Sharma, Mallickarjun Joshi
Summary: Through the investigation of archaeological data from the Ladakh region, it is found that there have been significant changes in climatic conditions from 19.6 to 6.1 thousand years ago, with a transition from westerly circulation to monsoon dominance. This change is closely related to the position of the ITCZ influenced by solar radiation and the variability of atmospheric circulation. The study also suggests the occurrence of an early wet phase of two-fold H1 events during a period of westerly dominance. The mid-Holocene period from 7.5 to 6.1 thousand years ago was characterized by westerly regain, coinciding with decreasing insolation, weakening monsoon, and enhanced El Nin & SIM;o activities.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Green & Sustainable Science & Technology
Gagan Mandal, Jia-Yuh Yu, Shih-Yu Lee
Summary: This study investigates the evolution of Southern Ocean dynamics during the last deglaciation and highlights the roles of Antarctic sea ice feedback and changes in orbital and meltwater forcings. The results show that wind stress primarily drove the Southern Ocean upwelling, and the melting of Antarctic sea ice influenced surface buoyancy flux. The experiments also demonstrate the dominant role of Northern Hemisphere meltwater discharge in the Meridional Overturning Circulation.
Article
Geography, Physical
Zhouqiao Zhao, Yonggang Liu, Haijin Dai
Summary: This study uses a model to evaluate the rate and timescale of marine ice deglaciation, finding that it takes at most 300 to 1500 years and results in the formation of a freshwater lid.
GLOBAL AND PLANETARY CHANGE
(2022)
Article
Geosciences, Multidisciplinary
Dhongil Lim, Jihun Kim, Jonguk Kim, Dongsung Kim, Dohyun Jeong, Haryun Kim, Zhaokai Xu
Summary: Sedimentary evidence from a well-dated sediment core from the Central Indian Ridge reveals enhanced volcanic activity during the last deglaciation period, possibly linked to sea-level variability. The study suggests that the increase in submarine and subaerial volcanic eruptions during the last deglaciation may have accelerated the rise of atmospheric CO2, reinforcing a positive feedback mechanism upon deglaciation.
Article
Geosciences, Multidisciplinary
Marie-Luise Kapsch, Uwe Mikolajewicz, Florian Ziemen, Clemens Schannwell
Summary: The last deglaciation period was characterized by drastic climate changes, primarily due to melting ice sheets. This study investigates the climate response differences in simulations of the last deglaciation using different boundary conditions and implementations proposed within the PMIP4 deglaciation protocol. The results reveal that the underlying ice-sheet reconstruction dominates the millennial-scale climate variability, and the timing and occurrence of observed climate events during the simulated deglacial period. The experiments also highlight the crucial role of the location and timing of ice-sheet meltwater release into the ocean on the oceanic response.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geography, Physical
Karol Tylmann, Szymon Uscinowicz
Summary: A new chronology of the last retreat of the Scandinavian Ice Sheet in the southern Baltic basin is proposed, based on Bayesian age modeling. The study shows that the retreat rates of the ice margin did not accelerate after the formation of an ice-dammed lake, suggesting that the ice margin was grounded and prevented from rapid retreat. The timing of the retreat phases corresponds to climatic fluctuations in the Northern Hemisphere.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geography, Physical
Kenji Izumi, Anne-Marie Lezine, Masa Kageyama
Summary: The inverse modeling through iterative forward modeling (IMIFM) approach is used to reconstruct the last deglaciation climates from central equatorial African mountains. Two different equilibrium vegetation models are used for evaluating the dependence of the results on the choice of vegetation model. The study shows that there are few common long-term trends of climatic responses during the last deglaciation among central equatorial African mountains' sites despite their close proximity.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
James Kershaw, Joseph A. Stewart, Ivo Strawson, Maria Luiza de Carvalho Ferreira, Laura F. Robinson, Katharine R. Hendry, Ana Samperiz, Andrea Burke, James W. B. Rae, Rusty D. Day, Peter J. Etnoyer, Branwen Williams, Vreni Haussermann
Summary: Based on the study of modern Stylasteridae corals, it is found that [Ba]SW and sample mineralogy are the main factors influencing coral Ba/Ca ratios, while seawater temperature has a weak influence. Paired Sr/Ca measurements suggest that the variability in scleractinian Ba/Ca may be related to varying degrees of Rayleigh fractionation during calcification. Stylasteridae corals have the potential to be an important new archive for paleoceanographic studies.
Article
Geochemistry & Geophysics
Sang Chen, Eloise F. M. Littley, James W. B. Rae, Christopher D. Charles, Yunbin Guan, Jess F. Adkins
Summary: Deep-sea corals serve as an important record of past oceans and studying their vital effects is crucial for paleoceanographic applications. By analyzing stable isotopes, minor and trace metals, we observed spatially coherent tracer correlations in individual corals. Our findings provide insights into the biomineralization mechanisms and the response of marine calcification to environmental stress. Understanding these mechanisms is essential for accurate use of deep-sea coral tracers and predicting the impact of ocean acidification.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geography, Physical
Tao Li, Tianyu Chen, Laura F. Robinson, Maoyu Wang, Gaojun Li, Yuanyuan Liu, Timothy D. J. Knowles
Summary: The loess-paleosol sequence on the Chinese Loess Plateau presents challenges in absolute dating due to the lack of directly datable materials. Fossil land snail shells have the potential for U-series dating of the loess deposits, but this method has not been extensively explored. This study investigates the geochemistry and diagenetic imprints of fossil land snail shells from the Mangshan loess-paleosol sequence in central China, demonstrating the potential for age determination of dust deposits using U-series dating.
QUATERNARY GEOCHRONOLOGY
(2023)
Article
Geochemistry & Geophysics
Jyun-Nai Wu, Ross Parnell-Turner, Daniel J. Fornari, Natalia Berrios-Rivera, Thibaut Barreyre, Jill M. McDermott
Summary: Fissures and faults in the crust help us understand how plate separation is accommodated by magma and brittle deformation. In a study of the East Pacific Rise, bathymetric data collected by autonomous underwater vehicles and remotely operated vehicles were used to map these features. The findings suggest that faulting plays a minimal role in plate separation compared to dike intrusion causing open cracks. The study also reveals the importance of reactivation of fissures during volcanic eruptions and provides insights into magma dynamics.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Natalia Berrios-Rivera, Jeffrey S. Gee, Ross Parnell-Turner, Sarah Maher, Jyun-Nai Wu, Daniel Fornari, Maurice Tivey, Milena Marjanovic, Thibaut Barreyre, Jill McDermott
Summary: By analyzing magnetic anomaly data near 9 degrees 50'N on the East Pacific Rise, researchers have discovered a continuous axial anomaly low, which is likely caused by variations in Earth's geomagnetic field intensity.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Qian Liu, Laura F. Robinson, Erica Hendy, Maria G. Prokopenko, Timothy D. J. Knowles, Tao Li, Ana Samperiz
Summary: Deep-sea bamboo corals have been used as archives for reconstructing past ocean changes, but the interpretation of geochemical signals recorded in their organic nodes, particularly regarding water depth, remains uncertain. Through isotopic analysis of bamboo corals collected from the central and eastern tropical Atlantic, contrasting results were found between the two regions. The carbon source for bamboo coral organic nodes may not always reside in the mixed layer, especially in oligotrophic regions, which has implications for age model development.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geosciences, Multidisciplinary
Tao Li, Gaojun Li, Tianyu Chen, Youbin Sun, Qiuzhen Yin, Zhipeng Wu, Laura F. Robinson, Le Li, Zeke Zhang, Xianqiang Meng, Liang Zhao, Junfeng Ji, Jun Chen
Summary: By integrating multi-proxy records from the loess sections on the central Chinese Loess Plateau, we find that the intensification of the East Asian winter monsoon during glacial inceptions is associated with millennial perturbations in the atmospheric circulation in response to abrupt North Atlantic cooling triggered by insolation. This climate teleconnection between the North Atlantic and East Asia is particularly effective when the Northern Hemisphere ice sheets reach a critical size.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Molly K. Anderson, Michael R. Perfit, Leah E. Morgan, Daniel J. Fornari, Michael Cosca, V. Dorsey Wanless
Summary: Our understanding of the relationship between off-axis magmatism and mid-ocean ridge spreading centers is limited, but high-precision 40Ar/39Ar geochronology has helped determine the ages of young lavas erupted near the East Pacific Rise axis. The eruption ages of seamounts are younger than the underlying lithosphere, suggesting prolonged off-axis magmatism for at least 2 million years at distances up to 90 km from the ridge axis.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Andre N. Paul, Joseph A. Stewart, Samuele Agostini, Linda A. Kirstein, Jan C. M. De Hoog, Ivan P. Savov, Kristina Walowski, James W. B. Rae, Tim Elliott
Summary: This study presents a low-blank sample preparation procedure for boron isotope measurement in silicate rocks using MC-ICP-MS. The method effectively addresses the challenges of volatilisation during silicate dissolution and contamination during chemical purification. The results demonstrate the accuracy and consistency of the method and reveal the heterogeneity in boron isotopes in the upper mantle.
GEOSTANDARDS AND GEOANALYTICAL RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Tianyu Chen, Laura F. Robinson, Tao Li, Andrea Burke, Xu Zhang, Joseph A. Stewart, Nicky J. White, Timothy D. J. Knowles
Summary: Proxy-based studies have linked the pre-industrial atmospheric p(CO2) rise to changes in Southern Ocean overturning. However, the history of polar ocean overturning and ventilation through the Holocene remains poorly constrained. This study suggests that long-term polar ocean overturning is not responsible for millennial atmospheric pCO(2) evolution, instead, changes in carbon redistribution and land organic carbon stock might regulate CO2 budget during this period.
Article
Chemistry, Analytical
Cheng Cao, Tao Li, Tianyu Chen, Gaojun Li, Wei Li, Jun Chen
Summary: There has been a growing interest in using lithium isotopes in marine carbonates to trace chemical weathering and clay formation. However, it is technically challenging to determine the Li isotope composition in carbonate samples due to the imperfect Li separation and low Li concentration in carbonates. A dual-column chromatography system for Li purification is presented, which has a large loading capacity, complete Li recovery, and efficient elution time. The procedure is validated with certified reference materials and the precision of Li isotope measurement is high.
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
(2023)
Article
Geosciences, Multidisciplinary
Eric W. Wolff, Andrea Burke, Laura Crick, Emily A. Doyle, Helen M. Innes, Sue H. Mahony, James W. B. Rae, Mirko Severi, R. Stephen J. Sparks
Summary: Volcanic eruptions are the main cause of climate variability, but estimating their frequency is challenging. Analysis of an Antarctic ice core showed that the frequency of eruptions has increased linearly over the past 200,000 years. The study also confirmed that the largest peaks in the ice core record are mostly from stratospheric eruptions.
CLIMATE OF THE PAST
(2023)