Abstract

This paper reports a study of xenoliths sampled in marine sedimentary carbonate rocks in fumaroles of the crater zone in the Second Cone of the GTFE (Great Tolbachik Fissure Eruption) North Vent. These rocks have been subjected to the action of the GTFE exhalative pneumatolytic fluids, resulting in carbonates giving rise to numerous compounds with mixed carbonate-sulfate-chloride anion radicals, which are treated as two interclass and nine intertype crystal-chemical hybrids. The patterns identified in the altered micro xenoliths, which consist in inhomogeneities of mineral paragenesis, are treated here as resulting from successive epigenetic transformation of the original carbonates to, at first, sulfate carbonates, then to carbonate sulfates, and subsequently to chloride-carbonate-sulfates and chlorides. Judging by an absence of signs of phase heterogeneity, the crystal-chemical hybrids studied here are homogeneous solid-phase mixtures of carbonates, sulfates, and chlorides in varying proportions. The carbonates in the micro xenoliths have isotopic compositions of carbon (δ¹³С_PDB = –5.34 ± 0.62‰) and oxygen (δ¹⁸O_SMOW = 24.09 ± 1.05‰) that are consistent with carbonates to be found in marine sedimentary limestones that were redeposited during volcanogenic transportation. The sulfate sulfur has the isotopic composition (δ³⁴S = 1.5–2‰) varying within the range of variation established for sulfates of volcanogenic origin. In the carbonaceous particles associated with micro xenoliths, the isotopic composition of carbon (δ¹³C_PDB = –27.37 ± 2.97‰) and of nitrogen (δ¹⁵N_Air = 6.74 ± 2.48‰) tend toward the mode in the distribution of these values in the ejecta of present-day continental volcanism. The crystal-chemical hybrids identified here furnish a typomorphic criterion for the exhalation fumarole facies and are treated as a previously unknown phenomenon of present-day volcanism.

中文翻译：

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喷气孔转化的地壳微捕虏体中含有混合阴离子自由基的矿物作为现代火山活动的新现象

摘要

本文报告了对 GTFE（大托尔巴奇克裂隙喷发）北喷口第二锥火山口区喷气孔中海相沉积碳酸盐岩中捕虏体样本的研究。这些岩石受到 GTFE 呼出气溶性流体的作用，导致碳酸盐产生许多具有混合碳酸盐-硫酸盐-氯化物阴离子基团的化合物，这些化合物被视为两个类间和九个类间晶体化学杂化物。在改变的微捕虏体中确定的模式，包括矿物共生的不均匀性，在这里被视为原始碳酸盐连续表观遗传转化的结果，首先是硫酸盐碳酸盐，然后是碳酸盐硫酸盐，然后是氯化物-碳酸盐-硫酸盐和氯化物。从不存在相异质性的迹象来看，这里研究的晶体化学杂化物是碳酸盐、硫酸盐和氯化物的不同比例的均匀固相混合物。微捕虏体中的碳酸盐具有碳同位素组成（δ¹³ С _PDB = –5.34 ± 0.62‰) 和氧气 (δ ¹⁸ O _SMOW = 24.09 ± 1.05‰) 与在火山活动期间重新沉积的海洋沉积石灰岩中发现的碳酸盐一致。硫酸盐硫的同位素组成 (δ ³⁴ S = 1.5–2‰) 在为火山成因硫酸盐确定的变化范围内变化。在与微捕虏体相关的碳质颗粒中，碳的同位素组成 (δ ¹³ C _PDB = –27.37 ± 2.97‰) 和氮的同位素组成 (δ ¹⁵ N _Air= 6.74 ± 2.48‰) 倾向于现代大陆火山喷出物中这些值的分布模式。此处确定的晶体化学杂化物为喷气孔相提供了典型标准，并被视为一种以前未知的现代火山现象。