A store of subducted carbon beneath Eastern China

• 来源期刊: 国家科学评论（英文版）
• 关键词: volcanic rocks regional distribution Hainan Island eastern China upper mantle carbon cycle form of
• 年，卷（期）: 2017,（1）
• 页码范围: 2
• 页数: 1页
• 语种: 英文
• DOI: 10.1093/nsr/nwx002

摘要

Geochemists' toolkit for tracing the global deep carbon cycle has recently been augmented by the analysis of magnesium isotopes.Light Mg-isotopic compositions normally occur uniquely in carbonates precipitated from seawater,either in the form of sedimentary limestones/dolomites or as sea-water-precipitated alteration products impregnating the oceanic crust.But Chinese geochemists have found that large numbers of volcanic rocks from the eastern part of China also contain the tell-tale signature of marine carbonates,indicating that these have been recycled through the upper mantle and into the sources of the volcanic rocks.Li and co-authors have reviewed the available data,adding many new analyses,in order to map the regional distribution of these anomalous Mg-isotopic compositions [1].What emerges is a remarkable isotopic map of young volcanic rocks from eastern China,showing light Mg-isotopic compositions in a swath of land extending from the east coast approximately 500 km inland and from Hainan Island in the south to the Russian border in the north.