前弓碳汇减少了长期的挥发性物质回收到地幔中
P H Barry1,2, J M de Moor3,4, D Giovannelli5,6,7,8
1Department of Earth Sciences, University of Oxford, Oxford, UK. pbarry@whoi.edu.
Nature
|April 26, 2019
概括
沉降板块将碳运送到地球的地幔中. 哥斯达黎加下方的板块释放的大部分碳被困在地石灰岩中,减少了深层地幔碳转移.
科学领域:
- 地质化学 地质化学
- 地质地质地质地质地质地
- 火山学 火山学是一门学科.
背景情况:
- 像碳这样的挥发性物质通过海洋地的降温被运送到地球地幔的收边缘.
- 了解这种挥发性转移的效率对于理解地球化学异质和地球氧化状态至关重要.
- 从前弧和后弧区域释放的挥发性物质的量化限制不如火山弧的限制.
研究的目的:
- 为了调查从哥斯达黎加前方弧线下面的沉降板块释放的碳的命运.
- 为了确定碳被隔离在地中的比例与转移到地幔的比例.
- 为了精确估计碳流入地球深层地幔的估计.
主要方法:
- 分析来自深层泉源的和碳同位素数据.
- 利用哥斯达黎加的两个横弧横断来捕捉空间变化.
- 通过石沉积和微生物同化量化碳封存.
主要成果:
- 大约91%的碳从哥斯达黎加前弓下方的石板和地幔中释放出来,被隔离在地内作为石.
- 另外3%的碳通过微生物化学和自otrophy.通过微生物化学和自otrophy.
- 预计前弓下方的板块每年释放的二氧化碳范围在1.2×10^8到1.3×10^10摩尔之间.
结论:
- 在这个区域的沉积过程中释放的大部分碳都被保留在地中,而不是转移到深层地幔.
- 之前估计的碳转移到深层地幔可能被高估了高达19%,这是由于地封存.
- 这项研究强调了forearc过程在调节全球碳循环中的重要作用.
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