Abstract

This article presents a comparative analysis of the isotope-geochemical characteristics of the products of activity of mud volcanoes (MVs) in the northwestern (Azerbaijan) and southeastern (Iran) parts of the South Caspian Basin (SCB). Gases of MVs in the studied regions are mainly of thermocatalytic origin, with the predominance of methane. High concentrations of nitrogen (up to 50%) are noted in the gases of some MVs in the Iranian sector. One distinctive feature of the MVs in the Azerbaijani part of the SCB is the presence of isotopically superheavy (>5‰) carbon dioxide, which is not typical for MVs in Iran. The waters of the MVs of Iran and most of the MVs of Azerbaijan are of the sodium chloride type. Isotopically heavy bicarbonate and carbonate ions, characteristic of the mud volcanic waters of Azerbaijan, are not typical for the volcanoes of the Iranian part of the SCB. Organic matter of rock ejecta of MVs in the Azerbaijani part of the SCB refers mainly to type II and type II–III kerogen, while in its Iranian part it is mainly type III kerogen. Mud volcanoes of Azerbaijan are characterized by a wide range of gas generation depths (10–16 km) and, accordingly, significant subvertical migration. The calculated maximum depth of the HC gas source in the Iranian part of the SCB does not exceed 12 km.

中文翻译：

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南里海盆地西北部（阿塞拜疆）和东南部（伊朗）部分泥火山岩石流体和有机质的同位素地球化学特征：比较分析

摘要

本文对南里海盆地 (SCB) 西北部（阿塞拜疆）和东南部（伊朗）泥火山 (MV) 活动产物的同位素地球化学特征进行了比较分析。研究区域中MV的气体主要是热催化来源的，其中以甲烷为主。伊朗地区一些MV 的气体中含有高浓度的氮气（高达 50%）。SCB阿塞拜疆部分的MV的一个显着特征是存在同位素超重（>5‰）二氧化碳，这在伊朗的MV中并不常见。伊朗MV和阿塞拜疆大部分MV的水域属于氯化钠类型。同位素重碳酸氢根和碳酸根离子是阿塞拜疆泥火山水域的特征，但对于SCB伊朗部分的火山来说并不典型。SCB阿塞拜疆部分MV岩石喷出物有机质主要为II型和II-III型干酪根，伊朗部分主要为III型干酪根。阿塞拜疆泥火山的特点是气体生成深度广泛（10-16 公里），因此存在显着的地下运移。经计算，SCB伊朗部分HC气源最大深度不超过12公里。