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DOI	10.1130/B35074.1
	The duration and magnitude of Cretaceous cool events: Evidence from the northern high latitudes
	Vickers M.L.; Price G.D.; Jerrett R.M.; Sutton P.; Watkinson M.P.; FitzPatrick M.
发表日期	2019
ISSN	167606
起始页码	1979
结束页码	1994
卷号	131 期号:2021-11-12
英文摘要	The Early Cretaceous (145-100 Ma) was characterized by long-term greenhouse climates, with a reduced equatorial to polar temperature gradient, although an increasingly large body of evidence suggests that this period was punctuated by episodic global "cold snaps." Understanding climate dynamics during this high-atmospheric CO2 period of Earth's history may have significant impact on how we understand climatic feedbacks and predict future global climate changes under an anthropogenically-driven high-pCO2 atmosphere. This study utilizes facies analysis to constrain the paleobathymetry of Lower Cretaceous glendonites- a pseudomorph after ikaite, a mineral that forms naturally at 7 °C or lower-from two paleo-high-latitude (60-70°N) sites in Svalbard, Arctic Norway, to infer global climatic changes during the Early Cretaceous. The original ikaite formed in the offshore transition zone of a shallow marine shelf at water depths of < 100 m, suggesting mean annual water temperatures of ≥ 7 °C at these depths at 60-70°N. We correlate glendonite-bearing horizons from Lower Cretaceous successions around the globe using carbon isotope stratigraphy, in conjunction with the pre-existing biostratigraphic framework, in order to infer northern hemispheric to global climatic cooling. A distinct interval of glendonites in the Northern Hemisphere, from sites > 60°N, spans the late Berriasian to earliest Barremian (at least 8.6 m.y.), significantly prolonging the duration of the previously hypothesized Valanginian cold snap (associated with the "Weissert Event"). Widespread glendonites occur again in late Aptian and extend to the early Albian, in both hemispheres, corroborating other proxy evidence for late Aptian cooling. The glendonites from Svalbard suggest that Cretaceous cold episodes were characterized with high latitude ( > 60°N) shallow water temperatures that are consistent with the existence of a small northern polar ice cap at this time. © 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/184933
作者单位	Department of Geosciences and Natural Resource Management, Københavns Universitet, Øster Voldgade 10, Copenhagen, 1350, Denmark; Centre for Research in Earth Sciences, School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, United Kingdom; School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom
推荐引用方式 GB/T 7714	Vickers M.L.,Price G.D.,Jerrett R.M.,et al. The duration and magnitude of Cretaceous cool events: Evidence from the northern high latitudes[J],2019,131(2021-11-12).
APA	Vickers M.L.,Price G.D.,Jerrett R.M.,Sutton P.,Watkinson M.P.,&FitzPatrick M..(2019).The duration and magnitude of Cretaceous cool events: Evidence from the northern high latitudes.Bulletin of the Geological Society of America,131(2021-11-12).
MLA	Vickers M.L.,et al."The duration and magnitude of Cretaceous cool events: Evidence from the northern high latitudes".Bulletin of the Geological Society of America 131.2021-11-12(2019).