气候变化领域集成服务门户(CCPortal): Paleogene topographic and climatic evolution of the Northern Rocky Mountains from integrated sedimentary and isotopic data

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DOI	10.1130/B32068.1
	Paleogene topographic and climatic evolution of the Northern Rocky Mountains from integrated sedimentary and isotopic data
	Schwartz T.M.; Methner K.; Mulch A.; Graham S.A.; Chamberlain C.P.
发表日期	2019
ISSN	167606
起始页码	1203
结束页码	1223
卷号	131 期号:2021-07-08
英文摘要	There is ongoing debate regarding the presence, timing, magnitude, and extent of high-elevation areas in the North American Cordillera during Late Cretaceous and Paleogene time. Large compilations of tectonic, sedimentary, and climatic data from the North American Cordillera and Western Interior region provide a continental-scale view of landscape evolution, but in spite of our broad understanding of Late Cretaceous-Paleogene events, the basin-scale relationships among tectonic activity, climatic change, and topographic evolution remain poorly understood in many parts of the Cordillera and Western Interior. The southwestern Montana sector of the North American Cordillera spans the structural boundary between the Sevier fold-and-thrust belt and the Laramide foreland province, ostensibly spanning the edge of a Paleogene high-elevation orogenic plateau. In order to assess the paleotopographic evolution of this area, we provide a synthesis of sedimentary, structural, igneous, paleolandscape, and paleoclimate data that includes a compilation of new and existing stable isotope data (paleosol carbonate δ18O and δ13C) from across the southwestern Montana region. Using detailed stratigraphic information as the context for interpretation, we integrated the multiple data types to evaluate Late Cretaceous-Paleogene landscape evolution in southwestern Montana, with special emphasis on δ18O and δ13C data. We also highlight apparent relationships between sedimentary environments (i.e., soil-forming conditions) and paleosol carbonate δ13C values, wherein the relative dryness of the local soil-forming environment correlates to the magnitude of δ13C values from paleosol carbonate (i.e., environmental dryness is positively correlated to δ13C). Results show that hinterland surface elevations progressively increased between Late Cretaceous and middle Eocene time, after which extensional reactivation across the fold-and-thrust belt region progressively lowered surface elevations and significantly modified the antecedent landscape: (1) Sevier- Laramide deformation resulted in the development of a rugged plateau with surface elevations > 2 km between ca. 65 and 58 Ma. (2) Maximum peak elevations increased to ≥4 km in the Sevier hinterland ca. 50 Ma following thermal uplift of the lithosphere; δ18O data support this, suggesting 2.3 km to 3 km of relief between the Sevier hinterland and the adjacent Laramide foreland at ca. 47 Ma. (3) Concurrent with elevation gain between ca. 58 and 53 Ma, warm/wet climatic conditions prompted deep fluvial incision into contractional terranes, generating a rugged, high-relief (up to 2 km) topography and a network of fluvially connected intermontane basins. (4) Extensional reactivation of structures in the fold-and-thrust belt region began ca. 50 Ma and continued through ca. 25 Ma; faulting locally amplified predecessor topographic relief but simultaneously lowered basin-floor surface elevations (and thus mean surface elevation). Extension also beheaded paleodrainages that had previously crossed the fold-and-thrust belt, producing ponded, normal fault-bounded basins on top of the fold-and-thrust belt. (6) Progressive extension was concurrent with progressive aridification between late Eocene and early Miocene time, which is supported by both δ18O and δ13C trends from across the basin network. © 2019 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/184940
作者单位	Geology and Geological Engineering Department, Colorado School of Mines, 1516 Illinois Street, Golden, CO 80403, United States; Senckenberg Biodiversity and Climate Research Centre, Georg-Voigt-Straße 14-16, Frankfurt am Main, 60325, Germany; Institute of Geosciences, Goethe University Frankfurt, Altenhöferallee 1, Frankfurt am Main, 60438, Germany; Department of Geological Sciences, Stanford University, 450 Serra Mall, Building 320, Stanford, CA 94305, United States
推荐引用方式 GB/T 7714	Schwartz T.M.,Methner K.,Mulch A.,et al. Paleogene topographic and climatic evolution of the Northern Rocky Mountains from integrated sedimentary and isotopic data[J],2019,131(2021-07-08).
APA	Schwartz T.M.,Methner K.,Mulch A.,Graham S.A.,&Chamberlain C.P..(2019).Paleogene topographic and climatic evolution of the Northern Rocky Mountains from integrated sedimentary and isotopic data.Bulletin of the Geological Society of America,131(2021-07-08).
MLA	Schwartz T.M.,et al."Paleogene topographic and climatic evolution of the Northern Rocky Mountains from integrated sedimentary and isotopic data".Bulletin of the Geological Society of America 131.2021-07-08(2019).