气候变化领域集成服务门户(CCPortal): The origin and evolution of breakouts in a cooling-limited rhyolite lava flow

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DOI	10.1130/B31931.1
	The origin and evolution of breakouts in a cooling-limited rhyolite lava flow
	Magnall N.; James M.R.; Tuffen H.; Vye-Brown C.; Ian Schipper C.; Castro J.M.; Davies A.G.
发表日期	2019
ISSN	167606
起始页码	137
结束页码	154
卷号	131 期号:2021-01-02
英文摘要	Understanding lava flow processes is important for interpreting existing lavas and for hazard assessments. Although substantial progress has been made for basaltic lavas our understanding of silicic lava flows has seen limited recent advance. In particular, the formation of lava flow breakouts, which represent a characteristic process in coolinglimited basaltic lavas, but has not been described in established models of rhyolite emplacement. Using data from the 2011-2012 rhyolite eruption of Puyehue-Cordón Caulle, Chile, we develop the first conceptual framework to classify breakout types in silicic lavas, and to describe the processes involved in their progressive growth, inflation, and morphological change. By integrating multiscale satellite, field, and textural data from Cordón Caulle, we interpret breakout formation to be driven by a combination of pressure increase (from local vesiculation in the lava flow core, as well as from continued supply via extended thermally preferential pathways) and a weakening of the surface crust through lateral spreading and fracturing. Small breakouts, potentially resulting more from local vesiculation than from continued magma supply, show a domed morphology, developing into petaloid as inflation increasingly fractures the surface crust. Continued growth and fracturing results in a rubbly morphology, with the most inflated breakouts developing into a cleft-split morphology, reminiscent of tumulus inflation structures seen in basalts. These distinct morphological classes result from the evolving relative contributions of continued breakout advance and inflation. The extended nature of some breakouts highlights the role of lava supply under a stationary crust, a process ubiquitous in inflating basalt lava flows that reflects the presence of thermally preferential pathways. Textural analyses of the Cordón Caulle breakouts also emphasize the importance of late-stage volatile exsolution and vesiculation within the lava flow. Although breakouts occur across the compositional spectrum of lava flows, the greater magma viscosity is likely to make late-stage vesiculation much more important for breakout development in silicic lavas than in basalts. Such late-stage vesiculation has direct implications for hazards previously recognized from silicic lava flows, enhancing the likelihood of flow front collapse, and explosive decompression of the lava core. © 2018 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/184963
作者单位	Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, United Kingdom; The Lyell Centre, British Geological Survey, Edinburgh, EH14 4AP, United Kingdom; School of Geography, Environment and Earth Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6140, New Zealand; Institute of Geosciences, University of Mainz, Becherweg 21, Mainz, D-55099, Germany; Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, United States
推荐引用方式 GB/T 7714	Magnall N.,James M.R.,Tuffen H.,et al. The origin and evolution of breakouts in a cooling-limited rhyolite lava flow[J],2019,131(2021-01-02).
APA	Magnall N..,James M.R..,Tuffen H..,Vye-Brown C..,Ian Schipper C..,...&Davies A.G..(2019).The origin and evolution of breakouts in a cooling-limited rhyolite lava flow.Bulletin of the Geological Society of America,131(2021-01-02).
MLA	Magnall N.,et al."The origin and evolution of breakouts in a cooling-limited rhyolite lava flow".Bulletin of the Geological Society of America 131.2021-01-02(2019).