气候变化领域集成服务门户(CCPortal): The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia

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DOI	10.1130/B35337.1
	The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia
	Stelten M.E.; Downs D.T.; Champion D.E.; Dietterich H.R.; Calvert A.T.; Sisson T.W.; Mahood G.A.; Zahran H.
发表日期	2020
ISSN	167606
起始页码	1381
结束页码	1403
卷号	132 期号:2021-07-08
英文摘要	Harrat Rahat, one of several large, basalt-dominated volcanic fields in western Saudi Arabia, is a prime example of continental, intraplate volcanism. Excellent exposure makes this an outstanding site to investigate changing volcanic flux and composition through time. We present 93 40Ar/39Ar ages and six 36Cl surface-exposure ages for volcanic deposits throughout northern Harrat Rahat that, when integrated with a new geologic map, define 12 eruptive stages. Exposed volcanic deposits in the study area erupted <1.2 Ma, and 214 of 234 eruptions occurred <570 ka. Two eruptions occurred in the Holocene, including a historically described basalt eruption in 1256 C.E. and a trachyte eruption newly recognized as Holocene (4.2 ± 5.2 ka). An estimated ~82 km3 (dense rock equivalent) of volcanic product have erupted since 1.2 Ma, though this is a lower limit due to concealment of deposits >570 ka. Over the past 570 k.y., the average eruption rate was 0.14 km3/k.y., but volcanism was episodic with periods alternating between low (0.04-0.06 km3/k.y.) and high (0.1-0.3 km3/k.y.) effusion rates. Before 180 ka, eruptions vented from the volcanic field's dominant eastern vent axis and from a subsidiary, diffuse, western vent axis. After 180 ka, volcanism focused along the eastern vent axis, and the composition of volcanism varied systematically along its length from basalt dominated in the north to trachyte dominated in the south. We hypothesize that these compositional variations <180 ka reflect the growth of a mafic intrusive complex beneath the southern portion of the vent axis, which led to the development of evolved magmas. © 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/184745
作者单位	U.S. Geological Survey, California Volcano Observatory, 345 Middlefield Road, Menlo Park, CA 94025, United States; U.S. Geological Survey, Alaska Volcano Observatory, 4230 University Drive Suite 100, Anchorage, AK 99058, United States; Stanford University, Department of Geological Sciences, Stanford, CA 94305, United States; Saudi Geological Survey, National Center for Earthquakes and Volcanoes, P.O. Box 54141, Jeddah, 21514, Saudi Arabia
推荐引用方式 GB/T 7714	Stelten M.E.,Downs D.T.,Champion D.E.,et al. The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia[J],2020,132(2021-07-08).
APA	Stelten M.E..,Downs D.T..,Champion D.E..,Dietterich H.R..,Calvert A.T..,...&Zahran H..(2020).The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia.Bulletin of the Geological Society of America,132(2021-07-08).
MLA	Stelten M.E.,et al."The timing and compositional evolution of volcanism within northern Harrat Rahat, Kingdom of Saudi Arabia".Bulletin of the Geological Society of America 132.2021-07-08(2020).