Chemical and thermal evolution of the upper mantle; implications for Earth's climate and biosphere and the nature of mantle convection

上地幔的化学和热演化；

• 批准号: 141928429
• 负责人: Privatdozent Dr. Marcel Regelous
• 金额: --
• 依托单位: GeoZentrum Nordbayern
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2012-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/141928429?language=en
• 关键词: Chemical; thermal; evolution; upper; mantle

The chemistry of mid-ocean ridge basalts (MORB) can be used to infer the temperature of the upper mantle, and ancient seafloor lavas preserve a record of mantle temperature and crustal thickness variations since the Mesozoic. Existing chemical data for old seafloor suggest that before 80 Ma the upper mantle was 60°C hotter than today. Mantle temperature variations on this scale impact on global climate and the biosphere. It has been argued that the Cretaceous greenhouse climate and sea-level highstand was triggered by higher than normal rates of oceanic crust production, due to higher mantle temperatures. However, there are presently very few chemical data for older oceanic crust, and most existing analyses were carried out on highly altered, phenocryst-rich, whole-rock samples. We will determine the changes in MORB chemistry over the past 170 Ma in each of the major ocean basins, avoiding the effects of alteration by analysing fresh basaltic glass using microanalytical techniques. Suitable samples for this study are available from the numerous DSDP/ODP sites drilled on old oceanic crust in the Pacific, Atlantic and Indian Oceans. The results will be used to examine the implications for the scale of mantle convection, and effects on sea-level, seawater chemistry and climate on timescales of 1-10 Ma.

洋中脊玄武岩（MORB）的化学成分可以用来推断上地幔的温度，而古代海底熔岩保存了中生代以来地幔温度和地壳厚度变化的记录。现有的旧海底化学数据表明，在80ma之前，上地幔比现在热60°C。这种尺度的地幔温度变化对全球气候和生物圈有影响。有人认为，白垩纪温室气候和海平面上升是由地幔温度升高导致的海洋地壳生成率高于正常水平引发的。然而，目前很少有关于更古老的海洋地壳的化学数据，而且大多数现有的分析都是在高度蚀变的、富含斑晶的整块岩石样本上进行的。我们将通过使用微量分析技术分析新鲜玄武岩玻璃，确定每个主要海洋盆地在过去170 Ma中MORB化学的变化，以避免变化的影响。在太平洋、大西洋和印度洋的古老海洋地壳上钻探了许多DSDP/ODP地点，可以获得适合本研究的样本。这些结果将用于研究地幔对流尺度的意义，以及在1-10 Ma时间尺度上对海平面、海水化学和气候的影响。

项目成果

Formation of the Troodos Ophiolite at a triple junction: Evidence from trace elements in volcanic glass

• DOI: 10.1016/j.chemgeo.2014.08.006
• 发表时间: 2014-10
• 期刊: Chemical Geology
• 影响因子: 3.9
• 作者: M. Regelous;K. Haase;S. Freund;M. Keith;C. Weinzierl;C. Beier;P. Brandl;T. Endres;H. Schmidt

Volcanism on the flanks of the East Pacific Rise: Quantitative constraints on mantle heterogeneity and melting processes

• DOI: 10.1016/j.chemgeo.2011.12.015
• 发表时间: 2012-03-02
• 期刊: CHEMICAL GEOLOGY
• 影响因子: 3.9
• 作者: Brandl, Philipp A.;Beier, Christoph;Galer, Stephen J. G.
• 通讯作者: Galer, Stephen J. G.

High mantle temperatures following rifting caused by continental insulation

• DOI: 10.1038/ngeo1758
• 发表时间: 2013-05-01
• 期刊: NATURE GEOSCIENCE
• 影响因子: 18.3
• 作者: Brandl, Philipp A.;Regelous, Marcel;Haase, Karsten M.
• 通讯作者: Haase, Karsten M.