Abstract The archaeology of the pre-contact Andes provides an ideal study of human responses to climate change given the region's extreme climatic variability, excellent archaeological preservation, and robust paleoclimate records. We evaluate the effects of climate change on the frequency of interpersonal violence in the south-central Andes from ca. 1.5–0.5 ka (AD 470–1540) by comparing incidents of skeletal trauma observed among 2753 crania from 58 sites to rates of ice accumulation at the Quelccaya Glacier. We find that, in the highlands, the odds of identifying inter-personal violence increase on average by a multiplicative factor of 2.4 (1.8–3.2; 95% C.I.) for every 10-centimeter decrease in annual ice accumulation. Our statistical analysis does not detect a relationship between ice accumulation and interpersonal violence rates among coastal or mid-elevation populations. This disparity likely resulted from variable economic and sociopolitical strategies at different elevations. The failure of rain-fed agriculture during periods of drought and concomitant dissolution of organizing polities likely predisposed highland populations to socioeconomic stress and violent competition for limited resources. Conversely, diversity among lowland and midland economies may have buffered against the effect of drought.
{"title":"Climate change intensified violence in the south-central Andean highlands from 1.5 to 0.5 ka","authors":"T. J. Snyder, R. Haas","doi":"10.1017/qua.2023.23","DOIUrl":"https://doi.org/10.1017/qua.2023.23","url":null,"abstract":"Abstract The archaeology of the pre-contact Andes provides an ideal study of human responses to climate change given the region's extreme climatic variability, excellent archaeological preservation, and robust paleoclimate records. We evaluate the effects of climate change on the frequency of interpersonal violence in the south-central Andes from ca. 1.5–0.5 ka (AD 470–1540) by comparing incidents of skeletal trauma observed among 2753 crania from 58 sites to rates of ice accumulation at the Quelccaya Glacier. We find that, in the highlands, the odds of identifying inter-personal violence increase on average by a multiplicative factor of 2.4 (1.8–3.2; 95% C.I.) for every 10-centimeter decrease in annual ice accumulation. Our statistical analysis does not detect a relationship between ice accumulation and interpersonal violence rates among coastal or mid-elevation populations. This disparity likely resulted from variable economic and sociopolitical strategies at different elevations. The failure of rain-fed agriculture during periods of drought and concomitant dissolution of organizing polities likely predisposed highland populations to socioeconomic stress and violent competition for limited resources. Conversely, diversity among lowland and midland economies may have buffered against the effect of drought.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"109 - 119"},"PeriodicalIF":2.3,"publicationDate":"2023-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44311561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Knott, S. Mahan, J. Bright, L. Langer, Adam Ramirez, Kyle R. McCarty, Anna L. Garcia
Abstract Deep Springs Valley (DSV) is a hydrologically isolated valley between the White and Inyo mountains that is commonly excluded from regional paleohydrology and paleoclimatology. Previous studies showed that uplift of Deep Springs ridge (informal name) by the Deep Springs fault defeated streams crossing DSV and hydrologically isolated the valley sometime after eruption of the Pleistocene Bishop Tuff (0.772 Ma). Here, we present tephrochronology and clast counts that reaffirms interruption of the Pliocene–Pleistocene hydrology and formation of DSV during the Pleistocene. Paleontology and infrared stimulated luminescence (IRSL) dates indicate a freshwater lake inundated Deep Springs Valley from ca. 83–61 ka or during Late Pleistocene Marine Isotope Stages 5a (MIS 5a; ca. 82 ka peak) and 4 (MIS 4; ca. 71–57 ka). The age of pluvial Deep Springs Lake coincides with pluvial lakes in Owens Valley and Columbus Salt Marsh and documents greater effective precipitation in southwestern North America during MIS 5a and MIS 4. In addition, we hypothesize that Deep Springs Lake was a balanced-fill lake that overflowed into Eureka Valley via the Soldier Pass wind gap during MIS 5a and MIS 4. DSV hydrology has implications for dispersal and endemism of the Deep Springs black toad (Anaxyrus exsul).
{"title":"Pliocene–Pleistocene hydrology and pluvial lake during Marine Isotope Stages 5a and 4, Deep Springs Valley, western Great Basin, Inyo County, California","authors":"J. Knott, S. Mahan, J. Bright, L. Langer, Adam Ramirez, Kyle R. McCarty, Anna L. Garcia","doi":"10.1017/qua.2023.20","DOIUrl":"https://doi.org/10.1017/qua.2023.20","url":null,"abstract":"Abstract Deep Springs Valley (DSV) is a hydrologically isolated valley between the White and Inyo mountains that is commonly excluded from regional paleohydrology and paleoclimatology. Previous studies showed that uplift of Deep Springs ridge (informal name) by the Deep Springs fault defeated streams crossing DSV and hydrologically isolated the valley sometime after eruption of the Pleistocene Bishop Tuff (0.772 Ma). Here, we present tephrochronology and clast counts that reaffirms interruption of the Pliocene–Pleistocene hydrology and formation of DSV during the Pleistocene. Paleontology and infrared stimulated luminescence (IRSL) dates indicate a freshwater lake inundated Deep Springs Valley from ca. 83–61 ka or during Late Pleistocene Marine Isotope Stages 5a (MIS 5a; ca. 82 ka peak) and 4 (MIS 4; ca. 71–57 ka). The age of pluvial Deep Springs Lake coincides with pluvial lakes in Owens Valley and Columbus Salt Marsh and documents greater effective precipitation in southwestern North America during MIS 5a and MIS 4. In addition, we hypothesize that Deep Springs Lake was a balanced-fill lake that overflowed into Eureka Valley via the Soldier Pass wind gap during MIS 5a and MIS 4. DSV hydrology has implications for dispersal and endemism of the Deep Springs black toad (Anaxyrus exsul).","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"160 - 178"},"PeriodicalIF":2.3,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41513865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Rodrigues, A. Keen-Zebert, S. Shepherd, M. Hudson, Chuck Bitting, Bradley G. Johnson, A. Langston
Abstract The Buffalo National River in northwest Arkansas preserves an extensive Quaternary record of fluvial bedrock incision and aggradation across lithologies of variable resistance. In this work, we apply optically stimulated luminescence (OSL) dating to strath and fill terraces along the Buffalo River to elucidate the role of lithology and climate on the development of the two youngest terrace units (Qtm and Qty). Our OSL ages suggest a minimum strath planation age of ca. 250 ka for the Qtm terraces followed by a ca. 200 ka record of aggradation. Qtm incision likely occurred near the last glacial maximum (LGM), prior to the onset of Qty fill terrace aggradation ca. 14 ka. Our terrace ages are broadly consistent with other regional terrace records, and comparison with available paleoclimatic archives suggests that terrace aggradation and incision occurred during drier and wetter hydrological conditions, respectively. Vertical bedrock incision rates were also calculated using OSL-derived estimates of Qtm strath planation and displayed statistically significant spatial variability with bedrock lithology, ranging from ~35 mm/ka in the higher resistance reaches and ~16 mm/ka in the lower resistance reaches. In combination with observations of valley width and terrace distribution, these results suggest that vertical processes outpace lateral ones in lithologic reaches with higher resistance.
{"title":"The role of lithology and climate on bedrock river incision and terrace development along the Buffalo National River, Arkansas","authors":"K. Rodrigues, A. Keen-Zebert, S. Shepherd, M. Hudson, Chuck Bitting, Bradley G. Johnson, A. Langston","doi":"10.1017/qua.2023.16","DOIUrl":"https://doi.org/10.1017/qua.2023.16","url":null,"abstract":"Abstract The Buffalo National River in northwest Arkansas preserves an extensive Quaternary record of fluvial bedrock incision and aggradation across lithologies of variable resistance. In this work, we apply optically stimulated luminescence (OSL) dating to strath and fill terraces along the Buffalo River to elucidate the role of lithology and climate on the development of the two youngest terrace units (Qtm and Qty). Our OSL ages suggest a minimum strath planation age of ca. 250 ka for the Qtm terraces followed by a ca. 200 ka record of aggradation. Qtm incision likely occurred near the last glacial maximum (LGM), prior to the onset of Qty fill terrace aggradation ca. 14 ka. Our terrace ages are broadly consistent with other regional terrace records, and comparison with available paleoclimatic archives suggests that terrace aggradation and incision occurred during drier and wetter hydrological conditions, respectively. Vertical bedrock incision rates were also calculated using OSL-derived estimates of Qtm strath planation and displayed statistically significant spatial variability with bedrock lithology, ranging from ~35 mm/ka in the higher resistance reaches and ~16 mm/ka in the lower resistance reaches. In combination with observations of valley width and terrace distribution, these results suggest that vertical processes outpace lateral ones in lithologic reaches with higher resistance.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"179 - 193"},"PeriodicalIF":2.3,"publicationDate":"2023-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48312548","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract There is a consensus in the literature that radiocarbon dating performed on bioapatite often produces ages younger than dating performed on collagen. We propose a general regression that could be used to convert the bioapatite radiocarbon ages to the simulated ages on collagen in fossil samples worldwide. This general regression presents several good indices of quality, high correlation (R2 = 0.98), lower values of percent predicted error (%PE = 0.01), and standard error of the estimate (%SEE = 21.83), showing that it is a good tool, as the predicted values are similar to those observed. Using this regression, we converted the radiocarbon ages of bioapatite to the expected age from the collagen fraction made for several taxa from the Brazilian Intertropical Region (BIR) and suggest that these dates could be 1–7 cal ka BP older than previously thought.
{"title":"Interrelation of radiocarbon ages from bone fractions in the Brazilian Intertropical Region","authors":"M. Dantas, A. Cherkinsky","doi":"10.1017/qua.2023.19","DOIUrl":"https://doi.org/10.1017/qua.2023.19","url":null,"abstract":"Abstract There is a consensus in the literature that radiocarbon dating performed on bioapatite often produces ages younger than dating performed on collagen. We propose a general regression that could be used to convert the bioapatite radiocarbon ages to the simulated ages on collagen in fossil samples worldwide. This general regression presents several good indices of quality, high correlation (R2 = 0.98), lower values of percent predicted error (%PE = 0.01), and standard error of the estimate (%SEE = 21.83), showing that it is a good tool, as the predicted values are similar to those observed. Using this regression, we converted the radiocarbon ages of bioapatite to the expected age from the collagen fraction made for several taxa from the Brazilian Intertropical Region (BIR) and suggest that these dates could be 1–7 cal ka BP older than previously thought.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"202 - 206"},"PeriodicalIF":2.3,"publicationDate":"2023-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45021553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Forman, Zequn Wu, Logan A Wiest, L. Marín, Connor Mayhack
Abstract Ubiquitous Holocene dune systems are associated with major west-to-east flowing rivers across the Southern Great Plains (SGP), USA. Critical questions remain as to whether aeolian activity reflects multiple environmental signatures, including increased sand supply from riverine sources. This research focused on the western Red River where geomorphic mapping revealed three terrace levels up to 16 m, buried partially by up to 10 m of aeolian sediments. Pedosedimentary facies analyses of sections and Geoprobe cores extracted from terraces and close-interval optically stimulated luminescence dating of quartz grains revealed two periods of fluvial aggradation at ca. 80 ka to ~5 to 8 m above the Red River forming the Vernon terrace, and at 30 to 13 ka to ~20–15 m, the highest identified Childress terrace. Net degradation of 20 m also occurred between 13 and 7 ka to 4 m below the current channel, reflecting regional fall in the groundwater level. The latest aggradation event, which built the lowest Luna terrace at ~2 m, ended 1.5 to 0.7 ka and was partially buried by fluvial-sourced dunes in the sixteenth and seventeenth centuries. This recent phase of aeolian deposition coincides with a comparatively wet period in the central United States during the Little Ice Age, rather than with regional drying.
{"title":"Late Quaternary fluvial and aeolian depositional environments for the western Red River, Southern Great Plains, USA","authors":"S. Forman, Zequn Wu, Logan A Wiest, L. Marín, Connor Mayhack","doi":"10.1017/qua.2023.15","DOIUrl":"https://doi.org/10.1017/qua.2023.15","url":null,"abstract":"Abstract Ubiquitous Holocene dune systems are associated with major west-to-east flowing rivers across the Southern Great Plains (SGP), USA. Critical questions remain as to whether aeolian activity reflects multiple environmental signatures, including increased sand supply from riverine sources. This research focused on the western Red River where geomorphic mapping revealed three terrace levels up to 16 m, buried partially by up to 10 m of aeolian sediments. Pedosedimentary facies analyses of sections and Geoprobe cores extracted from terraces and close-interval optically stimulated luminescence dating of quartz grains revealed two periods of fluvial aggradation at ca. 80 ka to ~5 to 8 m above the Red River forming the Vernon terrace, and at 30 to 13 ka to ~20–15 m, the highest identified Childress terrace. Net degradation of 20 m also occurred between 13 and 7 ka to 4 m below the current channel, reflecting regional fall in the groundwater level. The latest aggradation event, which built the lowest Luna terrace at ~2 m, ended 1.5 to 0.7 ka and was partially buried by fluvial-sourced dunes in the sixteenth and seventeenth centuries. This recent phase of aeolian deposition coincides with a comparatively wet period in the central United States during the Little Ice Age, rather than with regional drying.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"3 - 24"},"PeriodicalIF":2.3,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41364030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bianca Dickson, J. Sniderman, Vera A. Korasidis, J. Woodhead
Pollen preserved in caves provides a little-appreciated opportunity to study past vegetation and climate changes in regions where conventional wetland sediments are either unavailable, contain little organic matter, and/or are difficult to date accurately. Most palynology in caves has focused on clastic infill sediments, but pollen preserved in growing speleothems provides important new opportunities to develop vegetation and climatic records that can be dated accurately with radiometric methods. However, when pollen is present in speleothems, concentrations can vary by orders of magnitude, highlighting how little we know about the processes that transport pollen into caves and onto speleothem surfaces, and that determine the pollen's preservation probability. To explore these aspects of speleothem pollen taphonomy, we investigated the distribution of pollen and microscopic charcoal within several stalagmites from southwest Australia. We examined spatial patterns in pollen and charcoal preservation in order to distinguish whether observed gradients result from preservation or are products of systematic transport processes working along stalagmite surfaces. We find that pollen grains and charcoal fragments are located preferentially on the flanks of most stalagmites. This suggests that pollen grain and charcoal deposition on speleothems is influenced by transport and accumulation of detrital debris on growing surfaces. These insights will assist in future sampling campaigns focusing on speleothem pollen and charcoal contents.
{"title":"The distribution of fossil pollen and charcoal in stalagmites","authors":"Bianca Dickson, J. Sniderman, Vera A. Korasidis, J. Woodhead","doi":"10.1017/qua.2023.11","DOIUrl":"https://doi.org/10.1017/qua.2023.11","url":null,"abstract":"\u0000 Pollen preserved in caves provides a little-appreciated opportunity to study past vegetation and climate changes in regions where conventional wetland sediments are either unavailable, contain little organic matter, and/or are difficult to date accurately. Most palynology in caves has focused on clastic infill sediments, but pollen preserved in growing speleothems provides important new opportunities to develop vegetation and climatic records that can be dated accurately with radiometric methods. However, when pollen is present in speleothems, concentrations can vary by orders of magnitude, highlighting how little we know about the processes that transport pollen into caves and onto speleothem surfaces, and that determine the pollen's preservation probability. To explore these aspects of speleothem pollen taphonomy, we investigated the distribution of pollen and microscopic charcoal within several stalagmites from southwest Australia. We examined spatial patterns in pollen and charcoal preservation in order to distinguish whether observed gradients result from preservation or are products of systematic transport processes working along stalagmite surfaces. We find that pollen grains and charcoal fragments are located preferentially on the flanks of most stalagmites. This suggests that pollen grain and charcoal deposition on speleothems is influenced by transport and accumulation of detrital debris on growing surfaces. These insights will assist in future sampling campaigns focusing on speleothem pollen and charcoal contents.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":" ","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44047296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Patton, J. Shulmeister, Q. Hua, P. Almond, T. Rittenour, J. Hanson, Aloysius Grealy, Jack Gilroy, D. Ellerton
Abstract In this study, we assess charcoal records from eolian deposits within the Cooloola Sand Mass, a subtropical coastal dune system in eastern Australia, to determine whether they can be used as a proxy for Holocene fire history. We excavate four profiles in depositional wedges at the base of dune slipfaces (footslope deposits) and calculate charcoal concentrations for three size classes (180–250 μm, 250–355 μm, and 355 μm–2 mm) at predetermined depth intervals. Age–depth models are constructed for each profile using radiocarbon measurements (n = 46) and basal optically stimulated luminescence ages (n = 4). All records appear intact with little evidence of postdepositional mixing as demonstrated by minimal age reversals and consistent trends in charcoal concentration and accumulation rates (CHAR) among size classes. Combining all four records, we generate a ca. 7 cal ka BP terrestrial fire history that depicts distinct peaks representing periods of increased local fire activity at <0.3, 1.1–0.4, 2.2–1.6, 3.4–2.6, and 6.7–5.3 cal ka BP. Our findings parallel regional records and highlight the utility of dune footslopes as ecological and sedimentary archives. As dune fields are much more common than wetlands and lakes in semiarid and arid areas, these deposits have the potential to increase the spatial resolution of fire records globally.
{"title":"Reconstructing Holocene fire records using dune footslope deposits at the Cooloola Sand Mass, Australia","authors":"N. Patton, J. Shulmeister, Q. Hua, P. Almond, T. Rittenour, J. Hanson, Aloysius Grealy, Jack Gilroy, D. Ellerton","doi":"10.1017/qua.2023.14","DOIUrl":"https://doi.org/10.1017/qua.2023.14","url":null,"abstract":"Abstract In this study, we assess charcoal records from eolian deposits within the Cooloola Sand Mass, a subtropical coastal dune system in eastern Australia, to determine whether they can be used as a proxy for Holocene fire history. We excavate four profiles in depositional wedges at the base of dune slipfaces (footslope deposits) and calculate charcoal concentrations for three size classes (180–250 μm, 250–355 μm, and 355 μm–2 mm) at predetermined depth intervals. Age–depth models are constructed for each profile using radiocarbon measurements (n = 46) and basal optically stimulated luminescence ages (n = 4). All records appear intact with little evidence of postdepositional mixing as demonstrated by minimal age reversals and consistent trends in charcoal concentration and accumulation rates (CHAR) among size classes. Combining all four records, we generate a ca. 7 cal ka BP terrestrial fire history that depicts distinct peaks representing periods of increased local fire activity at <0.3, 1.1–0.4, 2.2–1.6, 3.4–2.6, and 6.7–5.3 cal ka BP. Our findings parallel regional records and highlight the utility of dune footslopes as ecological and sedimentary archives. As dune fields are much more common than wetlands and lakes in semiarid and arid areas, these deposits have the potential to increase the spatial resolution of fire records globally.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"67 - 89"},"PeriodicalIF":2.3,"publicationDate":"2023-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44623309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Dantas, Verônica Santos Gomes, A. Cherkinsky, H. I. de Araújo‐Júnior
Abstract We inferred the annual isotopic diet (δ13C) of an individual of the giant ground sloth Eremotherium laurillardi found in Toca dos Ossos (Ourolândia, Bahia, Brazil) through the extension of its third inferior molar. This individual lived in the region at 40,779–39,617cal yr BP. One year of its life was recorded in a length of 67 mm in the tooth. Two years were recorded in this molariform, during which the diet and climate did not change much, and substantial precipitation occurred during the middle of the year, which is in opposition to the modern pattern. The mean carbon (μδ13C = −13.9 ± 1.8‰) and oxygen (μδ18O = 22.5 ± 2.9‰) isotopic values were similar to values for other individuals of the species found in the same cave but different from the values found in other localities of the Brazilian Intertropical Region, which allows us to suggest that this region had more precipitation and lower temperatures in comparison to today. The oxygen isotopic values found in dated fossils of E. laurillardi and from two other taxa found in the same cave (Toxodon platensis, and Notiomastodon platensis) could help in the understanding of the climatic variation that occurred in the region.
摘要我们通过第三下臼齿的延伸推断了在Toca dos Ossos（Ourolândia，Bahia，Brazil）发现的巨型地懒Eremotherium laurilladi个体的年度同位素饮食（δ13C）。该个体生活在该地区，年BP为40779–39617卡。据记录，它的寿命为一年，牙齿长度为67毫米。有两年是以这种莫拉里形式记录的，在此期间，饮食和气候没有太大变化，年中出现了大量降水，这与现代模式相反。平均碳（μδ13C=-13.9±1.8‰）和氧（μδ18O=22.5±2.9‰）同位素值与同一洞穴中发现的其他物种的值相似，但与巴西热带地区其他地区的值不同，这使我们能够表明，与今天相比，该地区的降水量更多，温度更低。在E.laurillardi的年代化石和同一洞穴中发现的另外两个分类群（Toxodon platensis和Notiomastodon platensi）中发现的氧同位素值可能有助于理解该地区发生的气候变化。
{"title":"Annual isotopic diet (δ13C) of Eremotherium laurillardi (Lund, 1842) and climate variation (δ18O) through the late Pleistocene in the Brazilian Intertropical Region","authors":"M. Dantas, Verônica Santos Gomes, A. Cherkinsky, H. I. de Araújo‐Júnior","doi":"10.1017/qua.2023.17","DOIUrl":"https://doi.org/10.1017/qua.2023.17","url":null,"abstract":"Abstract We inferred the annual isotopic diet (δ13C) of an individual of the giant ground sloth Eremotherium laurillardi found in Toca dos Ossos (Ourolândia, Bahia, Brazil) through the extension of its third inferior molar. This individual lived in the region at 40,779–39,617cal yr BP. One year of its life was recorded in a length of 67 mm in the tooth. Two years were recorded in this molariform, during which the diet and climate did not change much, and substantial precipitation occurred during the middle of the year, which is in opposition to the modern pattern. The mean carbon (μδ13C = −13.9 ± 1.8‰) and oxygen (μδ18O = 22.5 ± 2.9‰) isotopic values were similar to values for other individuals of the species found in the same cave but different from the values found in other localities of the Brazilian Intertropical Region, which allows us to suggest that this region had more precipitation and lower temperatures in comparison to today. The oxygen isotopic values found in dated fossils of E. laurillardi and from two other taxa found in the same cave (Toxodon platensis, and Notiomastodon platensis) could help in the understanding of the climatic variation that occurred in the region.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"194 - 201"},"PeriodicalIF":2.3,"publicationDate":"2023-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44329213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kirby, Jazleen Barbosa, J. Carlin, Glen MacDonald, Jenifer A. Leidelmeijer, Nicole Bonuso, Jiwoo Han, B. Nauman, Judith Avila, A. Woodward, Sophia Obarr, C. Poulsen, Kevin Nichols, R. Ramezan
Abstract Perspectives on past climate using lake sediments are critical for assessing modern and future climate change. These perspectives are especially important for water-stressed regions such as the western United States. One such region is northwestern California (CA), where Holocene-length hydroclimatic records are scarce. Here, we present a 9000-year, relative lake level record from Maddox Lake (CA) using a multi-indicator approach. The Early Holocene is characterized by variably low lake levels with a brief excursion to wetter climates/relative highstand ca. 8.4–8.06 cal ka BP, possibly related to the 8.2 ka cold event and changing Atlantic Meridional Overturning Circulation (AMOC). From 5.2–0.55 cal ka BP, Maddox Lake experienced a long-term regression, tracking changes in summer-winter insolation, tropical and northeast Pacific SSTs, and the southward migration of the ITCZ. This gradual regression culminated in a pronounced relative lowstand during the Medieval Climatic Anomaly (MCA). A marked relative highstand followed the MCA, correlative to the Little Ice Age. The latter reflects a far-field response to North Atlantic volcanism, solar variability, and possibly changes in AMOC and Arctic sea ice extent. Our results further confirm the hydroclimatic sensitivity of northwest California to various forcings including those emanating from the North Atlantic.
摘要利用湖泊沉积物对过去气候的展望对于评估现代和未来气候变化至关重要。这些观点对于美国西部等缺水地区尤为重要。其中一个地区是加利福尼亚州西北部，那里的全新世水文气候记录很少。在这里，我们使用多指标方法展示了来自马多克斯湖（CA）的9000年相对湖泊水位记录。全新世早期的特点是湖泊水位变化低，短暂迁移到更潮湿的气候/相对高水位约8.4–8.06卡BP，可能与8.2卡冷事件和不断变化的大西洋经向翻转环流（AMOC）有关。从5.2–0.55 cal ka BP，Maddox湖经历了长期回归，跟踪了夏季-冬季日照、热带和东北太平洋SST以及ITCZ向南迁移的变化。这种逐渐的回归在中世纪气候异常（MCA）期间达到了显著的相对低点。MCA之后出现了明显的相对高位，与小冰河时代相关。后者反映了北大西洋火山活动、太阳变化以及AMOC和北极海冰范围的可能变化的远场响应。我们的结果进一步证实了加利福尼亚西北部的水文气候对各种强迫的敏感性，包括来自北大西洋的强迫。
{"title":"Holocene hydroclimatic variability recorded in sediments from Maddox Lake (northern California Coast Range)","authors":"M. Kirby, Jazleen Barbosa, J. Carlin, Glen MacDonald, Jenifer A. Leidelmeijer, Nicole Bonuso, Jiwoo Han, B. Nauman, Judith Avila, A. Woodward, Sophia Obarr, C. Poulsen, Kevin Nichols, R. Ramezan","doi":"10.1017/qua.2023.18","DOIUrl":"https://doi.org/10.1017/qua.2023.18","url":null,"abstract":"Abstract Perspectives on past climate using lake sediments are critical for assessing modern and future climate change. These perspectives are especially important for water-stressed regions such as the western United States. One such region is northwestern California (CA), where Holocene-length hydroclimatic records are scarce. Here, we present a 9000-year, relative lake level record from Maddox Lake (CA) using a multi-indicator approach. The Early Holocene is characterized by variably low lake levels with a brief excursion to wetter climates/relative highstand ca. 8.4–8.06 cal ka BP, possibly related to the 8.2 ka cold event and changing Atlantic Meridional Overturning Circulation (AMOC). From 5.2–0.55 cal ka BP, Maddox Lake experienced a long-term regression, tracking changes in summer-winter insolation, tropical and northeast Pacific SSTs, and the southward migration of the ITCZ. This gradual regression culminated in a pronounced relative lowstand during the Medieval Climatic Anomaly (MCA). A marked relative highstand followed the MCA, correlative to the Little Ice Age. The latter reflects a far-field response to North Atlantic volcanism, solar variability, and possibly changes in AMOC and Arctic sea ice extent. Our results further confirm the hydroclimatic sensitivity of northwest California to various forcings including those emanating from the North Atlantic.","PeriodicalId":49643,"journal":{"name":"Quaternary Research","volume":"115 1","pages":"90 - 108"},"PeriodicalIF":2.3,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42861045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：