Paleoceanography and Paleoclimatology最新文献_第10页

Expansion of Reducing Marine Environments During the Ireviken Biogeochemical Event: Evidence From the Altajme Core, Gotland, Sweden Ireviken生物地球化学事件期间减少海洋环境的扩展：来自瑞典哥德兰Altajme岩芯的证据

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-02-01 DOI: 10.1029/2022PA004484

B. Stolfus, Lindsi J. Allman, Seth A. Young, M. Calner, Emma R. Hartke, Stephan C. Oborny, A. Bancroft, B. Cramer

{"title":"Expansion of Reducing Marine Environments During the Ireviken Biogeochemical Event: Evidence From the Altajme Core, Gotland, Sweden","authors":"B. Stolfus, Lindsi J. Allman, Seth A. Young, M. Calner, Emma R. Hartke, Stephan C. Oborny, A. Bancroft, B. Cramer","doi":"10.1029/2022PA004484","DOIUrl":"https://doi.org/10.1029/2022PA004484","url":null,"abstract":"New δ34Spy (pyrite) and δ34SCAS (carbonate‐associated sulfate) across the Llandovery‐Wenlock boundary (∼432 Ma) provide evidence for the expansion of reduced marine environments during the Ireviken Biogeochemical Event. This event consists of a major positive carbon isotope excursion, increased biotic turnover, and other major perturbations and changes within biogeochemical cycles. This interval of time has been hypothesized to coincide with an expansion of reducing marine environments that caused increased organic carbon burial and led to the Ireviken positive carbon isotope excursion (ICIE). Previous high‐resolution carbon isotope work in the Altajme core from Gotland, Sweden provides the highest resolution record of the ICIE yet documented and provides an ideal expanded stratigraphic section to study this event. Local expansion of reduced marine environments within the deeper shelf setting of the Altajme core is indicated by a positive shift in δ34Spy values and increase in pyrite sulfur concentrations at the onset of the ICIE. These data are indicative of increased microbial sulfate reduction within this portion of the Baltic Basin. Combined with new δ34SCAS data from this core, as well as additional data from distant basins, the new data presented here suggest a global expansion of reduced environments led to an increase in organic carbon burial and the ICIE.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46164777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Carbon Cycle Responses to Changes in Weathering and the Long‐Term Fate of Stable Carbon Isotopes 碳循环对风化变化的响应和稳定碳同位素的长期命运

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-02-01 DOI: 10.1029/2022PA004577

A. Jeltsch-Thömmes, F. Joos

{"title":"Carbon Cycle Responses to Changes in Weathering and the Long‐Term Fate of Stable Carbon Isotopes","authors":"A. Jeltsch-Thömmes, F. Joos","doi":"10.1029/2022PA004577","DOIUrl":"https://doi.org/10.1029/2022PA004577","url":null,"abstract":"The causes of CO2 variations over the past million years remain poorly understood. Imbalances between the input of elements from rock weathering and their removal from the atmosphere‐ocean‐biosphere system to the lithosphere likely contributed to reconstructed changes. We employ the Bern3D model to investigate carbon‐climate responses to step‐changes in the weathering input of phosphorus, alkalinity, carbon, and carbon isotope ratio (δ13C) in simulations extending up to 600,000 years. CO2 and climate approach a new equilibrium within a few ten thousand years, whereas equilibrium is established after several hundred thousand years for δ13C. These timescales represent a challenge for the initialization of sediment‐enabled models and unintended drifts may be larger than forced signals in simulations of the last glacial–interglacial cycle. Changes in dissolved CO2 change isotopic fractionation during marine photosynthesis. This causes distinct spatio‐temporal perturbations in δ13C and affects the burial flux of 13C. We force a cost‐efficient emulator, based on the Bern3D results, with contrasting literature‐based weathering histories over the last 800 thousand years. Glacial–interglacial amplitudes of up to 30 ppm in CO2, 0.05‰ in δ13C, and ∼15 mmol m−3 in deep ocean CO32− ${text{CO}}_{3}^{2-}$ are emulated for changes in carbonate rock weathering. Plausible input from the decomposition of organic matter on shelves causes variations of up to 10 ppm in CO2, 0.09‰ in δ13C, and 5 mmol m−3 in CO32− ${text{CO}}_{3}^{2-}$ , highlighting the non‐negligible effect of weathering‐burial imbalances.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47635833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Late Miocene to Present Paleoclimatic and Paleoenvironmental Evolution of the South China Sea Recorded in the Magneto‐Cyclostratigraphy of IODP Site U1505 IODP U1505遗址磁旋地层记录的南海晚中新世至今古气候和古环境演化

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-31 DOI: 10.1029/2022PA004547

Yunfeng Nie, Huaichun Wu, S. Satolli, E. Ferré, M. Shi, Q. Fang, Ye Xu, Shihong Zhang, Haiyan Li, Tianshui Yang

{"title":"Late Miocene to Present Paleoclimatic and Paleoenvironmental Evolution of the South China Sea Recorded in the Magneto‐Cyclostratigraphy of IODP Site U1505","authors":"Yunfeng Nie, Huaichun Wu, S. Satolli, E. Ferré, M. Shi, Q. Fang, Ye Xu, Shihong Zhang, Haiyan Li, Tianshui Yang","doi":"10.1029/2022PA004547","DOIUrl":"https://doi.org/10.1029/2022PA004547","url":null,"abstract":"The continuous sedimentary cores recovered at the International Ocean Discovery Program (IODP) Site U1505, Expedition 368, provide an opportunity for paleoceanography and paleoclimate reconstruction in the continental margin of the northern South China Sea (SCS). In this study, we conducted detailed rock‐ and paleomagnetic studies on 420 discrete samples from the top ∼200 m of the synthetic records of Holes U1505C and U1505D. Rock magnetic analyses indicate that low‐coercivity pseudosingle domain magnetite dominates as the primary ferromagnetic mineral of Site U1505. The magnetostratigraphic age model was constructed by correlating the interpreted polarity sequence with the Geomagnetic Polarity Time Scale 2020 with the constraints of the biostratigraphic data and the distribution probability of the age of each polarity zone provided by a Dynamic Time Warping algorithm. The Milankovitch cycles of the short eccentricity, obliquity, and precession cycles were identified in the magnetic susceptibility (MS) and natural gamma radiation (NGR) series based on paleomagnetic results. We established an ∼9 Myr high‐resolution astronomical time scale by tuning the MS and NGR records to the global oxygen isotope curves, the obliquity, and the eccentricity curves of the La2004 astronomical solution. Our new age model reveals detailed sedimentation rate variations and a ∼500 kyr hiatus across the Brunhes‐Matuyama boundary related to local tectonic activity. These results lay the foundation for understanding the paleoceanography and paleoclimate evolution of the SCS.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43716123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Issue Information 问题信息

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-26 DOI: 10.1002/palo.21172

引用次数: 0

North Atlantic Drift Sediments Constrain Eocene Tidal Dissipation and the Evolution of the Earth‐Moon System 北大西洋漂移沉积物制约始新世潮汐耗散和地月系统的演化

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-25 DOI: 10.1029/2022PA004555

D. De Vleeschouwer, D. Penman, S. D’haenens, Fei Wu, T. Westerhold, M. Vahlenkamp, C. Cappelli, C. Agnini, W. E. Kordesch, D. J. King, Robin van der Ploeg, H. Pälike, S. Turner, P. Wilson, R. Norris, J. Zachos, S. Bohaty, P. Hull

{"title":"North Atlantic Drift Sediments Constrain Eocene Tidal Dissipation and the Evolution of the Earth‐Moon System","authors":"D. De Vleeschouwer, D. Penman, S. D’haenens, Fei Wu, T. Westerhold, M. Vahlenkamp, C. Cappelli, C. Agnini, W. E. Kordesch, D. J. King, Robin van der Ploeg, H. Pälike, S. Turner, P. Wilson, R. Norris, J. Zachos, S. Bohaty, P. Hull","doi":"10.1029/2022PA004555","DOIUrl":"https://doi.org/10.1029/2022PA004555","url":null,"abstract":"Cyclostratigraphy and astrochronology are now at the forefront of geologic timekeeping. While this technique heavily relies on the accuracy of astronomical calculations, solar system chaos limits how far back astronomical calculations can be performed with confidence. High‐resolution paleoclimate records with Milankovitch imprints now allow reversing the traditional cyclostratigraphic approach: Middle Eocene drift sediments from Newfoundland Ridge are well‐suited for this purpose, due to high sedimentation rates and distinct lithological cycles. Per contra, the stratigraphies of Integrated Ocean Drilling Program Sites U1408–U1410 are highly complex with several hiatuses. Here, we built a two‐site composite and constructed a conservative age‐depth model to provide a reliable chronology for this rhythmic, highly resolved (<1 kyr) sedimentary archive. Astronomical components (g‐terms and precession constant) are extracted from proxy time‐series using two different techniques, producing consistent results. We find astronomical frequencies up to 4% lower than reported in astronomical solution La04. This solution, however, was smoothed over 20‐Myr intervals, and our results therefore provide constraints on g‐term variability on shorter, million‐year timescales. We also report first evidence that the g4–g3 “grand eccentricity cycle” may have had a 1.2‐Myr period around 41 Ma, contrary to its 2.4‐Myr periodicity today. Our median precession constant estimate (51.28 ± 0.56″/year) confirms earlier indicators of a relatively low rate of tidal dissipation in the Paleogene. Newfoundland Ridge drift sediments thus enable a reliable reconstruction of astronomical components at the limit of validity of current astronomical calculations, extracted from geologic data, providing a new target for the next generation of astronomical calculations.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43506667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Proxy‐Model Comparison for the Eocene‐Oligocene Transition in Southern High Latitudes 南部高纬度始新世-渐新世过渡的代理模型比较

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-25 DOI: 10.1029/2022PA004496

E. J. Tibbett, N. Burls, D. Hutchinson, S. Feakins

{"title":"Proxy‐Model Comparison for the Eocene‐Oligocene Transition in Southern High Latitudes","authors":"E. J. Tibbett, N. Burls, D. Hutchinson, S. Feakins","doi":"10.1029/2022PA004496","DOIUrl":"https://doi.org/10.1029/2022PA004496","url":null,"abstract":"The Eocene‐Oligocene transition (EOT) marks the shift from greenhouse to icehouse conditions at 34 Ma, when a permanent ice sheet developed on Antarctica. Climate modeling studies have recently assessed the drivers of the transition globally. Here we revisit those experiments for a detailed study of the southern high latitudes in comparison to the growing number of mean annual sea surface temperature (SST) and mean air temperature (MAT) proxy reconstructions, allowing us to assess proxy‐model temperature agreement and refine estimates for the magnitude of the pCO2 forcing of the EOT. We compile and update published proxy temperature records on and around Antarctica for the late Eocene (38–34 Ma) and early Oligocene (34–30 Ma). Compiled SST proxies cool by up to 3°C and MAT by up to 4°C between the timeslices. Proxy data were compared to previous climate model simulations representing pre‐ and post‐EOT, typically forced with a halving of pCO2. We scaled the model outputs to identify the magnitude of pCO2 change needed to drive a commensurate change in temperature to best fit the temperature proxies. The multi‐model ensemble needs a 30 or 33% decrease in pCO2, to best fit MAT or SST proxies respectively. These proxy‐model intercomparisons identify declining pCO2 as the primary forcing of EOT cooling, with a magnitude (200 or 243 ppmv) approaching that of the pCO2 proxies (150 ppmv). However individual model estimates span a decrease of 66–375 ppmv, thus proxy‐model uncertainties are dominated by model divergence.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44621237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Impact of Different Atmospheric CO2 Concentrations on Large Scale Miocene Temperature Signatures 不同大气CO2浓度对中新世大尺度温度特征的影响

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-23 DOI: 10.1029/2022PA004438

Akil Hossain, G. Knorr, W. Jokat, G. Lohmann, K. Hochmuth, P. Gierz, K. Gohl, C. Stepanek

{"title":"The Impact of Different Atmospheric CO2 Concentrations on Large Scale Miocene Temperature Signatures","authors":"Akil Hossain, G. Knorr, W. Jokat, G. Lohmann, K. Hochmuth, P. Gierz, K. Gohl, C. Stepanek","doi":"10.1029/2022PA004438","DOIUrl":"https://doi.org/10.1029/2022PA004438","url":null,"abstract":"Based on inferences from proxy records the Miocene (23.03–5.33 Ma) was a time of amplified polar warmth compared to today. However, it remains a challenge to simulate a warm Miocene climate and pronounced polar warmth at reconstructed Miocene CO2 concentrations. Using a state‐of‐the‐art Earth‐System‐Model, we implement a high‐resolution paleobathymetry and simulate Miocene climate at different atmospheric CO2 concentrations. We estimate global mean surface warming of +3.1°C relative to the preindustrial at a CO2 level of 450 ppm. An increase of atmospheric CO2 from 280 to 450 ppm provides an individual warming of ∼1.4°C, which is as strong as all other Miocene forcing contributions combined. Substantial changes in surface albedo are vital to explain Miocene surface warming. Simulated surface temperatures fit well with proxy reconstructions at low‐ to mid‐latitudes. The high latitude cooling bias becomes less pronounced for higher atmospheric CO2 concentrations. At such CO2 levels simulated Miocene climate shows a reduced polar amplification, linked to a breakdown of seasonality in the Arctic Ocean. A pronounced warming in boreal fall is detected for a CO2 increase from 280 to 450 ppm, in comparison to weaker warming for CO2 changes from 450 to 720 ppm. Moreover, a pronounced warming in winter is detected for a CO2 increase from 450 to 720 ppm, in contrast to a moderate summer temperature increase, which is accompanied by a strong sea‐ice concentration decline that promotes cloud formation in summer via enhanced moisture availability. As a consequence planetary albedo increases and dampens the temperature response to CO2 forcing at a warmer Miocene background climate.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44374653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Hydroclimate Variability in the Equatorial Western Indian Ocean for the Last 250,000 Years 近25万年来赤道西印度洋的水文气候变化

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-21 DOI: 10.1029/2022PA004530

G. Windler, J. Tierney, P. deMenocal

{"title":"Hydroclimate Variability in the Equatorial Western Indian Ocean for the Last 250,000 Years","authors":"G. Windler, J. Tierney, P. deMenocal","doi":"10.1029/2022PA004530","DOIUrl":"https://doi.org/10.1029/2022PA004530","url":null,"abstract":"Indian Ocean sea surface temperatures impact precipitation across the basin through coupled ocean‐atmosphere responses to changes in climate. To understand the hydroclimate response over the western Indian Ocean and equatorial east Africa to different forcing mechanisms, we present four new proxy reconstructions from core VM19‐193 (2.98°N, 51.47°E) that span the last 250 ky. Sub‐surface water temperatures (Sub‐T; TEX86) show strong precessional (23 ky) variability that is primarily influenced by maximum incoming solar radiation (insolation) during the Northern Hemisphere spring season, likely indicating that local insolation dominates the upper water column at this tropical location over time. Leaf waxes, on the other hand, reflect two different precipitation signals: δ13Cwax (in phase with boreal fall insolation) is likely reflecting vegetation changes in response to local rainfall over east Africa, whereas δDprecip (primarily driven by boreal summer insolation) represents changes in regional circulation associated with the summer monsoon. Glacial‐interglacial changes in ocean temperatures support glacial shelf exposure over the Maritime Continent in the eastern Indian Ocean and the subsequent weakening of the Indian Walker Circulation as a mechanism driving 100 ky climate variability across the tropical Indo‐Pacific. Additionally, the 100 ky spectral power in δDprecip supports a basin‐wide weakening of summer monsoon circulation in response to glacial climates. Overall, the proxy records from VM19‐193 indicate that both precession and glacial‐interglacial cycles exert control over hydroclimate at this tropical location.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45787365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Authigenic and Detrital Carbonate Nd Isotope Records Reflect Pulses of Detrital Material Input to the Labrador Sea During the Heinrich Stadials 自生和碎屑碳酸盐Nd同位素记录反映海因里希时期输入拉布拉多海碎屑物质的脉冲

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-17 DOI: 10.1029/2022PA004470

A. Filippova, M. Frank, M. Kienast, M. Gutjahr, E. Hathorne, C. Hillaire‐Marcel

{"title":"Authigenic and Detrital Carbonate Nd Isotope Records Reflect Pulses of Detrital Material Input to the Labrador Sea During the Heinrich Stadials","authors":"A. Filippova, M. Frank, M. Kienast, M. Gutjahr, E. Hathorne, C. Hillaire‐Marcel","doi":"10.1029/2022PA004470","DOIUrl":"https://doi.org/10.1029/2022PA004470","url":null,"abstract":"Limited constraints on the variability of the deep‐water production in the Labrador Sea complicate reconstructions of the strength of the Atlantic Meridional Overturning Circulation (AMOC) during the Late Quaternary. Large volumes of detrital carbonates were repeatedly deposited in the Labrador Sea during the last 32 kyr, potentially affecting radiogenic Nd isotope signatures. To investigate this the Nd isotope compositions of deep and intermediate waters were extracted from the authigenic Fe‐Mn oxyhydroxide fraction, foraminiferal coatings, the residual silicates and leachates of dolostone grains. We provide a first order estimation of Nd release via dissolution of detrital carbonates and its contribution to the authigenic ԑNd signatures in the Labrador Sea. During the Last Glacial Maximum the Nd isotope signatures in the Labrador Sea would allow active water mass mixing with more radiogenic ɛNd values (−12.6 and −14) prevailing in its eastern part whereas less radiogenic values (ɛNd ∼ −18.4) were found on the western Labrador slope. The deposition of detrital carbonates during Heinrich stadials (2,1) was accompanied by negative detrital and authigenic Nd isotope excursions (ɛNd ∼ −31) that were likely controlled by dissolution of dolostone or dolostone associated mineral inclusions. This highly unradiogenic signal dominated the authigenic phases and individual water masses in the Labrador Sea, serving as potential source of highly unradiogenic Nd to the North Atlantic region, while exported southward. The Holocene authigenic ɛNd signatures of the coatings and leachates significantly differed from those of the detrital silicates, approaching modern bottom water mass signatures during the Late Holocene.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47647898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Paleoclimate Changes in the Pacific Northwest Over the Past 36,000 Years From Clumped Isotope Measurements and Model Analysis 从混杂同位素测量和模式分析看太平洋西北部36000年来的古气候变化

IF 3.5 2区地球科学

Paleoceanography and Paleoclimatology Pub Date : 2023-01-13 DOI: 10.1029/2021PA004266

R. Lopez‐Maldonado, J. Bateman, A. Ellis, N. Bader, P. Ramirez, Alexandrea Arnold, Osinachi Ajoku, Hung‐I Lee, G. Jesmok, D. Upadhyay, B. Mitsunaga, B. Elliott, C. Tabor, A. Tripati

{"title":"Paleoclimate Changes in the Pacific Northwest Over the Past 36,000 Years From Clumped Isotope Measurements and Model Analysis","authors":"R. Lopez‐Maldonado, J. Bateman, A. Ellis, N. Bader, P. Ramirez, Alexandrea Arnold, Osinachi Ajoku, Hung‐I Lee, G. Jesmok, D. Upadhyay, B. Mitsunaga, B. Elliott, C. Tabor, A. Tripati","doi":"10.1029/2021PA004266","DOIUrl":"https://doi.org/10.1029/2021PA004266","url":null,"abstract":"Since the last glacial period, North America has experienced dramatic changes in regional climate, including the collapse of ice sheets and changes in precipitation. We use clumped isotope (∆47) thermometry and carbonate δ18O measurements of glacial and deglacial pedogenic carbonates from the Palouse Loess to provide constraints on hydroclimate changes in the Pacific Northwest. We also employ analysis of climate model simulations to help us further provide constraints on the hydroclimate changes in the Pacific Northwest. The coldest clumped isotope soil temperatures T( ∆ ${increment}$47) (13.5 ± 1.9°C to 17.1 ± 1.7°C) occurred ∼34,000–23,000 years ago. Using a soil‐to‐air temperature transfer function, we estimate Last Glacial Maximum (LGM) mean annual air temperatures of ∼−5.5°C and warmest average monthly temperatures (i.e., mean summer air temperatures) of ∼4.4°C. These data indicate a regional warming of 16.4 ± 2.6°C from the LGM to the modern temperatures of 10.9°C, which was about 2.5–3 times the global average. Proxy data provide locality constraints on the boundary of the cooler anticyclone induced by LGM ice sheets, and the warmer cyclone in the Eastern Pacific Ocean. Climate model analysis suggests regional amplification of temperature anomalies is due to the proximal location of the study area to the Laurentide Ice Sheet margin and the impact of the glacial anticyclone on the region, as well as local albedo. Isotope‐enabled model experiments indicate variations in water δ18O largely reflect atmospheric circulation changes and enhanced rainout upstream that brings more depleted vapor to the region during the LGM.","PeriodicalId":54239,"journal":{"name":"Paleoceanography and Paleoclimatology","volume":" ","pages":""},"PeriodicalIF":3.5,"publicationDate":"2023-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47694220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0