Spatial distribution of eclogite in the Slave cratonic mantle: The role of subduction
Spatial distribution of eclogite in the Slave cratonic mantle: The role of subduction
复制标题
从属克拉通地幔中榴辉岩的空间分布：俯冲作用
DOI：
10.1016/j.tecto.2016.01.034
复制
发表时间：
2016
期刊：
影响因子：
2.9
通讯作者：
P. Strand
中科院分区：
文献类型：
--
作者：
M. Kopylova;Y. Beausoleil;A. Goncharov;J. Burgess;P. Strand
对加拿大Slave克拉通不同地区4个金伯利岩管中的240个捕虏体进行了温压测量，重建了榴辉岩的空间分布。深度估计的准确性是通过使用最近校准的温度计，以及约束当地的橄榄岩地热，岩石学筛选不切实际的温度估计，和所有数据的内部一致性的温度投影。深度估计的基础上的矿物化学和岩相学的新数据148榴辉岩捕虏体从杰里科和Muskox金伯利岩的北方奴隶克拉通和以前报告的分析95榴辉岩从Diavik和Ekati金伯利岩（中央奴隶）。大部分北方Slave榴辉岩的地壳俯冲起源发生在110-170 km处，比大部分中央Slave地壳榴辉岩（120-210 km）浅。这些榴辉岩种群的相同的地质年代学历史和中央和北方奴隶克拉通之间的陡峭的缝合线边界的情况下，建议横向连续性的地幔层相对丰富的榴辉岩。我们解释了榴辉岩的分布部分保存的叠瓦状和塑性分散的洋板形成的东倾元古代俯冲。榴辉岩定位的深度与地球物理测绘的不连续面不相关。橄榄岩捕虏体的温压法约束的奴隶克拉通的亏损岩石圈的基础与加厚的岩石圈板的基础一致，这支持回收的海洋岩石圈的贡献，形成的地幔根。它的结构可能受到环俯冲作用的保护，并使浅太古代岩石圈免受破坏性的软流圈交代作用的影响。
We reconstructed the spatial distribution of eclogites in the cratonic mantle based on thermobarometry for ~ 240 xenoliths in 4 kimberlite pipes from different parts of the Slave craton (Canada). The accuracy of depth estimates is ensured by the use of a recently calibrated thermometer, projection of temperatures onto well-constrained local peridotitic geotherms, petrological screening for unrealistic temperature estimates, and internal consistency of all data. The depth estimates are based on new data on mineral chemistry and petrography of 148 eclogite xenoliths from the Jericho and Muskox kimberlites of the northern Slave craton and previously reported analyses of 95 eclogites from Diavik and Ekati kimberlites (Central Slave). The majority of Northern Slave eclogites of the crustal, subduction origin occurs at 110–170 km, shallower than in the majority of the Central Slave crustal eclogites (120–210 km). The identical geochronological history of these eclogite populations and the absence of steep suture boundaries between the central and northern Slave craton suggest the lateral continuity of the mantle layer relatively rich in eclogites. We explain the distribution of eclogites by partial preservation of an imbricated and plastically dispersed oceanic slab formed by easterly dipping Proterozoic subduction. The depths of eclogite localization do not correlate with geophysically mapped discontinuities. The base of the depleted lithosphere of the Slave craton constrained by thermobarometry of peridotite xenoliths coincides with the base of the thickened lithospheric slab, which supports contribution of the recycled oceanic lithosphere to formation of the cratonic root. Its architecture may have been protected by circum-cratonic subduction and shielding of the shallow Archean lithosphere from the destructive asthenospheric metasomatism.