气候变化领域集成服务门户(CCPortal): Magmatism in the North Atlantic Igneous Province; mantle temperatures, rifting and geodynamics

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DOI	10.1016/j.earscirev.2019.02.011
	Magmatism in the North Atlantic Igneous Province; mantle temperatures, rifting and geodynamics
	Hole M.J.; Natland J.H.
发表日期	2020
ISSN	0012-8689
卷号	206
英文摘要	We have re-evaluated mantle potential temperature estimates for the North Atlantic Igneous Province (NAIP). Temperature estimates involving olivine addition to pillow-lava glasses are unreliable because host glasses formed along the liquid+olivine+plagioclase cotectic and not just the olivine liquidus. Additionally, magma chamber processes can generate picritic lavas containing only magnesian olivine, but picrites alone do not require high mantle temperatures. Furthermore, petrological models tend to over-estimate TP in picrites containing appreciable accumulative olivine further confusing the issue. Selected aphyric lavas from West Greenland, which cannot have accumulated olivine, suggest maximum TP~1500 °C. Petrological models for Icelandic glasses suggest a maximum TP~1450 °C which is consistent with olivine-melt and olivine-spinel equilibration temperatures. However, melting of ‘damp’ peridotite beneath Iceland would reduce this estimate perhaps by 50 °C. The NAIP mantle was lithologically and chemically heterogeneous and was made of a hybrid pyroxenite-peridotite lithology, the pyroxenite component being derived from recycling of subducted slabs. However, there is no necessity for the subducted slabs to have been recycled to the core-mantle boundary. Pyroxenite could have been derived from Caledonian-aged slabs that also hosted helium with high 3He/4He within the shallow mantle, which was inherited by Palaeocene or young melts. The pyroxenite component was more readily fusible than the peridotite component under the same P-T conditions, allowing variations in melt production rate throughout the province. Melting of lithologically variable mantle is consistent with observed radiogenic isotope variability in Icelandic basalts and related trace-element variations in throughout the NAIP. We propose that magmatism in the NAIP resulted from extensional tectonics above ‘warm’ mantle that had been internally heated beneath thick continental lithosphere prior to continental break up. Only in areas of extension did magmatism occur, thus explaining the apparently widespread initial phase of magmatic activity. © 2019
语种	英语
scopus关键词	Caledonian orogeny; continental lithosphere; core-mantle boundary; geodynamics; igneous province; lithology; magmatism; mantle structure; P-T conditions; Paleocene; petrology; pillow lava; rifting; temperature profile
来源期刊	EARTH-SCIENCE REVIEWS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/209618
作者单位	Department of Geology & Petroleum Geology, University of Aberdeen, Aberdeen, AB243UE, United Kingdom; RSMAS/MGS University of Miami, Miami, FL 33149, United States
推荐引用方式 GB/T 7714	Hole M.J.,Natland J.H.. Magmatism in the North Atlantic Igneous Province; mantle temperatures, rifting and geodynamics[J],2020,206.
APA	Hole M.J.,&Natland J.H..(2020).Magmatism in the North Atlantic Igneous Province; mantle temperatures, rifting and geodynamics.EARTH-SCIENCE REVIEWS,206.
MLA	Hole M.J.,et al."Magmatism in the North Atlantic Igneous Province; mantle temperatures, rifting and geodynamics".EARTH-SCIENCE REVIEWS 206(2020).