Explosive activity of the last 1000 years at La Soufriere, St Vincent, Lesser Antilles
Explosive activity of the last 1000 years at La Soufriere, St Vincent, Lesser Antilles
复制标题
DOI：
10.1016/j.jvolgeores.2019.01.002
复制
发表时间：
2019-02-01
影响因子：
2.9
通讯作者：
Scarpati, C.
中科院分区：
文献类型：
--
作者：
Cole, P. D.;Robertson, R. E. A.;Scarpati, C.
描述了圣文森特岛拉苏弗里耶尔火山过去 1000 年来的爆炸活动产物。不同火山喷发的日期是根据当代记录、实地考察和放射性碳测年的信息确定的。火山渣流型火山碎屑密度流 (PDC) 在历史喷发（1979、1902-03、1718/1812 CE）和史前喷发（类似于 1580 和 1440 CE）的产物中占主导地位，并具有与几次喷发相关的次要沉降成分。放射性碳测年表明，这六次喷发定义了一个粗略的周期性，其静止期在 77 年至 140 年之间，并且在最近的时期系统地减少。两次史前喷发，分别类似于公元 1440 年和 1580 年，都产生了岩浆火山灰沉降物和 PDC，并且由比历史喷发稍微更进化的岩浆供给。公元 1902 年和 1812 年的火山喷发时含有丰富的火山灰，可能存在岩浆活动。公元 1902-03 年的标志性火山喷发产生了放射状分布的 PDC，导致约 1500 人死亡。然而，这些沉积物仅存有少量残余物，并且无法从保存的地质中确定其原始分布，这对灾害研究具有重要意义。石化工作表明，爆炸性喷发涉及的岩浆成分范围相当狭窄，主要由玄武质安山岩组成。 1902-03 年的喷发涉及 1903 年 3 月的晚期玄武岩成分。然而，过去 1000 年的活动产生了明显更均匀的岩浆，其范围比文献中先前报道的较早的喷发时期更窄，这表明岩浆库供给系统随时间发生了显着变化。 (C) 2019 Elsevier B.V. 保留所有权利。
The products of explosive activity of La Soufriere volcano on the island of St Vincent over the last 1000 years are described. Dates for the different eruptions were determined using information from contemporary accounts, fieldwork and radiocarbon dating. Scoria-flow type pyroclastic density currents (PDCs) dominate the products of both the historical eruptions (1979, 1902-03, 1718/1812 CE) and prehistoric eruptions (similar to 1580 and 1440 CE) with subordinate fallout components associated with several eruptions. Radiocarbon dating shows that these six eruptions define a crude cyclicity with repose periods ranging between 77 and similar to 140 years and systematically decreasing in more recent times.Two prehistoric eruptions, in similar to 1440 and 1580 CE respectively, both produced magmatic lapilli fallout and PDCs, and were fed by slightly more evolved magmas than the historical eruptions. The eruptions in 1902 and 1812 CE had ash-rich, possible phreatomagmatic activity at their onset.The iconic 1902-03 CE eruption generated radial distributed PDCs, which were responsible for the deaths of similar to 1500 people. However, only small remnants of these deposits remain and the original distribution cannot be determined from the preserved geology, which has important implications for hazard studies.Petrochemical work has shown that magmas involved in the explosive eruptions were quite narrow in compositional range, mainly comprising basaltic andesites. The 1902-03 eruption involved a late stage basaltic component in March 1903. However, activity in the last 1000 years generated notably more homogeneous magmas with a narrower range than the older eruptive periods previously reported in the literature, suggesting a significant variation in the magmatic reservoir feeding system with time. (C) 2019 Elsevier B.V. All rights reserved.