The products of primary magma fragmentation finally revealed by pumice agglomerates
The products of primary magma fragmentation finally revealed by pumice agglomerates
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DOI：
10.1130/g48902.1
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发表时间：
2021-11-01
期刊：
影响因子：
5.8
通讯作者：
Wright, Heather M. N.
中科院分区：
文献类型：
--
作者：
Giachetti, Thomas;Trafton, Kathleen R.;Wright, Heather M. N.
在火山管道中迅速减压后，岩浆破裂成火山灰块大小的碎片，为次普林尼期和普林尼期的爆炸性喷发提供动力，可能产生破坏性的火山碎屑福尔斯和流动。因此，评估岩浆如何分解成碎片至关重要。然而，这项任务是困难的，因为整个过程的地下性质，因为原始碎片的原始大小被二次破碎和膨胀所改变。对普林尼亚期和普林尼期浮石火山砾的新的结构观察表明，岩浆破碎的一些初级产物在岩浆破碎后的几秒钟内通过烧结而幸存下来。它们的大小分布反映了能量的碎裂，与快速减压实验的产品。因此，浮石聚集体提供了一个独特的窗口，以前无法访问的主要破碎过程，并可用于确定潜在的能量的破碎。
Following rapid decompression in the conduit of a volcano, magma breaks into ashto block-sized fragments, powering explosive sub-Plinian and Plinian eruptions that may generate destructive pyroclastic falls and flows. It is thus crucial to assess how magma breaks up into fragments. This task is difficult, however, because of the subterranean nature of the entire process and because the original size of pristine fragments is modified by secondary fragmentation and expansion. New textural observations of sub-Plinian and Plinian pumice lapilli reveal that some primary products of magma fragmentation survive by sintering together within seconds of magma break-up. Their size distributions reflect the energetics of fragmentation, consistent with products of rapid decompression experiments. Pumice aggregates thus offer a unique window into the previously inaccessible primary fragmentation process and could be used to determine the potential energy of fragmentation.