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DOI	10.1016/j.palaeo.2020.109610
	Stable isotope compositions of herbivore teeth indicate climatic stability leading into the mid-Miocene Climatic Optimum; in Idaho; U.S.A
	Harris E.B.; Kohn M.J.; Strömberg C.A.E.
发表日期	2020
ISSN	0031-0182
卷号	546
英文摘要	The effects of global climate change are manifested at the regional level; consequently, evaluation of links between palaeoenvironmental change and turnover of past biotas must use regional-scale climate data. Here we test whether climate change influenced faunal and floral patterns leading up to, and during, the mid-Miocene Climatic Optimum (MMCO) based on datasets collected in the Railroad Canyon section (RCS), central-eastern Idaho, U.S.A. Specifically, we use isotope compositions of herbivore tooth enamel to investigate how Mean Annual Precipitation (MAP), Mean Annual Temperature (MAT), Cold Month Mean Temperature (CMMT), and temperature seasonality varied through the RCS and how this local record compares to global climate reconstructions. Isotope compositions of teeth from the fossil equid Merychippus and rhinocerotid Diceratherium were compared across five time bins from c. 23 to c. 15 Ma. Bulk δ18O values of both taxa indicate that meteoric water compositions were unchanged through the study interval (consistently c. −15.6‰) but were c. 1.9‰ higher than current regional meteoric water. This difference points to warmer climates in central-eastern Idaho during the Miocene, post-middle Miocene topographic uplift in western North America, and/or shifts to air mass trajectories. Serial sampling of enamel shows seasonal fluctuations in water compositions and temperature. Bulk δ13C values indicate an average MAP of 190 (range: 10–510 mm·yr−1), with no significant change through the study interval, comparable to today's MAP (236 mm·yr−1). The reconstructed semi-arid, seasonal, warm climate for the RCS agrees with phytolith assemblage data from the same strata indicating dominantly open, grassy habitats. However, it is inconsistent with previously held ideas of warm-wet mid-Miocene climates in the northern Rocky Mountains (NRM) based on paleosol analyses. Our inferred, stable climate conditions for the MMCO of the NRM contrast with coeval records from Europe and Asia indicating sustained or enhanced warm and wet climates. These differences point to a decoupling of regional climate from global trends and highlight the necessity of studying regional variation to understand the biotic impacts of global climate change. © 2020 Elsevier B.V.
英文关键词	Climate; Enamel; Mid-Miocene Climatic Optimum; Paleoecology; Seasonality
语种	英语
scopus关键词	air mass; climate change; global climate; isotopic composition; meteoric water; paleoclimate; paleoecology; paleosol; regional climate; seasonality; stable isotope; tooth; Asia; Europe; Idaho; Rocky Mountains; United States; Equidae; Rhinocerotidae
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150550
作者单位	Department of Biology and Burke Museum of Natural History and Culture, University of Washington, Box 351800, Life Sciences Building, Seattle, WA 98195, United States; Department of Geosciences, Boise State University, 1910 University Drive, Boise, ID 83725, United States
推荐引用方式 GB/T 7714	Harris E.B.,Kohn M.J.,Strömberg C.A.E.. Stable isotope compositions of herbivore teeth indicate climatic stability leading into the mid-Miocene Climatic Optimum; in Idaho; U.S.A[J],2020,546.
APA	Harris E.B.,Kohn M.J.,&Strömberg C.A.E..(2020).Stable isotope compositions of herbivore teeth indicate climatic stability leading into the mid-Miocene Climatic Optimum; in Idaho; U.S.A.Palaeogeography, Palaeoclimatology, Palaeoecology,546.
MLA	Harris E.B.,et al."Stable isotope compositions of herbivore teeth indicate climatic stability leading into the mid-Miocene Climatic Optimum; in Idaho; U.S.A".Palaeogeography, Palaeoclimatology, Palaeoecology 546(2020).