气候变化领域集成服务门户(CCPortal): Recognizing long-runout pyroclastic flow deposits using paleomagnetism of ash

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DOI	10.1130/B35029.1
	Recognizing long-runout pyroclastic flow deposits using paleomagnetism of ash
	Lerner G.A.; Cronin S.J.; Turner G.M.; Piispa E.J.
发表日期	2019
ISSN	167606
起始页码	1783
结束页码	1793
卷号	131 期号:2021-11-12
英文摘要	Quantifying the spread of > 600 °C pyroclastic flows (more broadly termed pyroclastic density currents-PDCs) is important because they regularly cause major volcanic catastrophes. Far from volcanic flanks, non-welded PDC deposits can be difficult to distinguish from cold-emplaced volcano-sedimentary units. A key indicator of high temperature is the coherence of magnetic remanence among different lithic clasts in a deposit. In long-runout PDCs, distal deposits are dominated by ash particles ( < 2 mm diameter), often lacking clasts large enough for conventional paleomagnetic sampling. Here we demonstrate a method of consolidating and sampling oriented blocks of friable ash material with a strengthening compound. This method was used to show that a > 25 km runout mass-flow deposit from the 2518-m-high Mt. Taranaki (New Zealand) was emplaced as a hot PDC, contrary to an earlier cold lahar interpretation. We corroborate the results from ash with data from clast samples at some sites and show that the matrix was emplaced at temperatures of at least 250 °C, while clasts were deposited at up to 410 °C. Our case-study raises concerns for hazard-identification at stratovolcanoes worldwide. In the Mt. Taranaki case we demonstrate that PDCs traveled > 9 km farther than previously estimated-also well beyond the "normal" PDC hazard zones at stratovolcanoes (10 or 15 km from source). Thus, attention should be paid to deposits in the 15-25 km range in other volcanic settings, where large populations are potentially unaware of PDC risk. © 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/184934
作者单位	School of Environment, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand; School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand; School of Geological Sciences and Engineering, Universidad Yachay Tech, Hacienda San Jose S/N y Projecto Yachay, Canton Urcuquí, Imbabura, 100115, Ecuador
推荐引用方式 GB/T 7714	Lerner G.A.,Cronin S.J.,Turner G.M.,et al. Recognizing long-runout pyroclastic flow deposits using paleomagnetism of ash[J],2019,131(2021-11-12).
APA	Lerner G.A.,Cronin S.J.,Turner G.M.,&Piispa E.J..(2019).Recognizing long-runout pyroclastic flow deposits using paleomagnetism of ash.Bulletin of the Geological Society of America,131(2021-11-12).
MLA	Lerner G.A.,et al."Recognizing long-runout pyroclastic flow deposits using paleomagnetism of ash".Bulletin of the Geological Society of America 131.2021-11-12(2019).