Anomalous thermal structures of subduction zones revealed by thermal properties of clinochlore at high temperature and pressure
Anomalous thermal structures of subduction zones revealed by thermal properties of clinochlore at high temperature and pressure
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DOI：
10.1130/b37134.1
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Nao Cai
中科院分区：
文献类型：
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作者：
Ruixin Zhang;Duojun Wang;Huiwen Tan;Hongbin Lu;Sheqiang Miao;Xiang Gao;Kenan Han;Peng Chen;Chuanjiang Liu;Nao Cai
Clinochlore is a major hydrous mineral in subduction zones, and its thermophysical properties at high temperature and pressure are critical to the thermal structures of subduction zones. Here, we used the pulse heating method to measure thermal diffusivity and thermal conductivity of clinochlore at 0.5−4.0 GPa and 298−1373 K. Our results indicate that upon heating, thermal diffusivity and thermal conductivity decrease from ∼9.6 × 10−7 m2 s−1 to 4.3 × 10−7 m2 s−1 and from ∼3.5 W m−1 K−1 to 1.9 W m−1 K−1, respectively, before dehydration, but this trend is reversed after dehydration. In general, the pressure derivatives for the thermal transport properties also decrease with temperature before dehydration. Lattice heat transfer is the dominant mechanism before dehydration, but fluid is involved after dehydration. Using our experimental data, we simulated the temperature distribution of subducting slabs containing clinochlore at volume fractions of 0%, 10%, 20%, 50%, and 100%. Our simulations showed that the heat insulation effect caused by the presence of clinochlore could result in an increase in temperature by 30−60 K for the upper part of the subducting slab.
