气候变化领域集成服务门户(CCPortal): Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins

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DOI	10.1016/j.palaeo.2019.03.016
	Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins
	Albanesi G.L.; Barnes C.R.; Trotter J.A.; Williams I.S.; Bergström S.M.
发表日期	2020
ISSN	0031-0182
卷号	549
英文摘要	Stratigraphic, palaeontologic, and palaeomagnetic data support a hypothesis that argues for the Argentine Precordillera rifting from the southwestern margin of Laurentia in low latitudes during the Cambrian, migrating across the Iapetus Ocean, colliding with the Gondwanan margin in the late Middle Ordovician, and receiving glaciogenic sediments in the Late Ordovician. An alternative model proposes that the Precordillera originated as a low-latitude segment of Gondwana, migrated southward through major transform faulting toward high latitudes in the late Middle Ordovician, to reach its present position in the Devonian. New conodont oxygen isotope compositions (δ18Ophos) have been determined by ion microprobe SHRIMP II using samples from both the Precordillera and Laurentia (Marathon area of Texas, Wilcox Pass in Alberta, and western Newfoundland). Significantly, the δ18O values of conodonts from all four widely separated areas show a consistent pattern of a cyclic but overall increasing trend in δ18O (ca. 16 to 18‰) hence ocean cooling through the Early and Middle Ordovician. An apparent change occurs at the basal Late Ordovician, where δ18O values obtained from conodonts in the uppermost sample from the Precordillera are significantly higher (+1.5‰) than those from Laurentia. Albeit from a single sample, this higher value implies significantly cooler conditions, as would be anticipated with a southerly (poleward) migration of the Precordillera (irrespective of either hypothesis). The virtual absence of conodont-bearing carbonates in most of the Precordilleran Upper Ordovician precluded analysis of younger samples. When combined with existing macrofaunal and palaeomagnetic data, the oxygen isotope data would tend to favour the model of a drift of the Precordillera from tropical to higher latitudes during the Ordovician; however, further studies are needed to determine unequivocally whether the Precordillera originated from southern Laurentia (Ouachita embayment). These new oxygen isotope values provide the best and regionally most consistent data through the Early-Middle Ordovician. © 2019 Elsevier B.V.
英文关键词	Cuyania; Iapetus Ocean; Marathon area Texas; SHRIMP ion microprobe; Western Newfoundland; Wilcox Pass Alberta
语种	英语
scopus关键词	comparative study; conodont; ion microprobe; latitudinal gradient; Laurentia; Ordovician; oxygen isotope; rifting; thermometry; Alberta; Attica; Canada; Greece; Marathon; Newfoundland; Newfoundland and Labrador; Precordillera; Texas; United States
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/150511
作者单位	CICTERRA (CONICET-UNC) – Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 1611, Córdoba, X5016GCA, Argentina; School of Earth and Ocean Sciences, University of Victoria, P.O. Box 1700, Victoria, B.C. V8W 2Y2, Canada; School of Earth and Environment and UWA Oceans Institute, The University of Western Australia, Perth, WA 6009, Australia; Research School of Earth Sciences, The Australian National University, Canberra, ACT 2601, Australia; School of Earth Sciences, Division of Earth History, The Ohio State University, 125 S. Oval Mall, Columbus, OH 43210, United States
推荐引用方式 GB/T 7714	Albanesi G.L.,Barnes C.R.,Trotter J.A.,et al. Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins[J],2020,549.
APA	Albanesi G.L.,Barnes C.R.,Trotter J.A.,Williams I.S.,&Bergström S.M..(2020).Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins.Palaeogeography, Palaeoclimatology, Palaeoecology,549.
MLA	Albanesi G.L.,et al."Comparative Lower-Middle Ordovician conodont oxygen isotope palaeothermometry of the Argentine Precordillera and Laurentian margins".Palaeogeography, Palaeoclimatology, Palaeoecology 549(2020).