Abstract

This article presents the results of a comparative analysis of the isotopic–geochemical composition of gases from igneous/hydrothermal and sedimentary volcanic systems in various regions of the world based on a large amount of literature data and the results of the author’s own research. The purpose of the study is to evaluate the nature of gases of various volcanic systems using known genetic criteria developed as a result of many years of research by a number of scientists from around the world. Data processing for the purpose of comparative analysis and corresponding graphical constructions have been performed using standard computer programs. A comprehensive analysis of the isotopic composition of carbon-rich gases and the isotopic ratio of helium (R/Ra) allows us to draw the following main conclusions: (1) hydrocarbon (HC) gases of the studied volcanic systems have different genetic sources: (a) abiogenic in igneous and carbonic sedimentary volcanic systems, (b) predominantly abiogenic–biogenic in the hydrothermal system, and (c) biogenic (thermogenic–microbial) in sedimentary volcanoes; (2) the content of abiogenic methane in the magmatic/hydrothermal system is insignificant and does not exceed 1%; (3) the isotope composition of CO₂ and the ratio of isotopes of radiogenic and air argon (⁴⁰Ar/³⁶Ar) in igneous volcanoes varies within very narrow limits when compared with sedimentary volcanoes. However, the use of these parameters as an unambiguous genetic criterion is not possible.

中文翻译：

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岩浆和沉积火山系统气体的同位素组成：回顾与比较分析

摘要

本文根据大量文献资料和作者本人的研究成果，介绍了对世界各地区火成/热液和沉积火山系统气体的同位素地球化学组成进行比较分析的结果。该研究的目的是利用世界各地许多科学家多年研究成果制定的已知遗传标准来评估各种火山系统的气体性质。已经使用标准计算机程序进行了用于比较分析和相应图形构造的数据处理。综合分析富碳气体的同位素组成和氦同位素比（R/Ra），我们可以得出以下主要结论：（1）所研究的火山系统的碳氢化合物（HC）气体具有不同的成因来源： (a) 火成岩和碳质沉积火山系统中的非生物成因，(b) 热液系统中主要是非生物成因-生物成因，以及 (c) 沉积火山中的生物成因（热成因-微生物）；(2) 岩浆/热液系统中非生物甲烷含量微乎其微，不超过1%；(3)与沉积火山相比，火成火山中CO ₂同位素组成以及放射源与空气氩的同位素比( ⁴⁰ Ar/ ^{36 Ar) 变化范围非常窄。}然而，使用这些参数作为明确的遗传标准是不可能的。