Silicate mineral compositions for metamorphic schist and amphibolite, northern Madison Range, southwestern Montana

Abstract: These data are mineral compositions measured by electron microprobe, presented in the 2015 publication in Lithosphere by Condit et al. Two samples of Bear Basin schist (GP7c and GP7f) and one mafic dike sample (AA09-61) were targeted to help constrain conditions and timing of metamorphism and deformation in the Gallatin Peak terrane of the northern Madison Range, southwestern Montana. The Bear Basin schist was sampled in a pelitic horizon because the mineral assemblages are amenable to quantitative thermobarometry and monazite geochronology. The mafic dikes were targeted because they represent the youngest metamorphosed and deformed intrusive units in the study area. Pressure and temperature (P-T) equilibrium conditions calculated from all three samples constrain representative metamorphic conditions in the northwest portion of the Gallatin Peak terrane. Geochronology data for these samples is also presented in the Lithosphere publication.

Other Description: Cailey B. Condit, Kevin H. Mahan, Alexis K. Ault, and Rebecca M. Flowers, (2015), "Foreland-directed propagation of high-grade tectonism in the deep roots of a Paleoproterozoic collisional orogen, SW Montana, USA." Lithosphere, 7(6): 625-645.

摘要：本数据集为电子探针（electron microprobe）测得的矿物成分数据，相关成果发表于2015年《Lithosphere》期刊的Condit等人的研究论文中。本次研究选取了2份熊盆地片岩样品（GP7c与GP7f）及1份镁铁质岩墙样品（AA09-61），旨在限定美国蒙大拿州西南部麦迪逊山脉北部加拉廷峰地体的变质作用与变形作用的条件及时限。熊盆地片岩采自泥质岩层位，因其矿物组合可开展定量温压计（thermobarometry）计算与独居石（monazite）地质年代学研究。选取镁铁质岩墙样品的原因在于，它们是研究区内最新一期经历变质与变形作用的侵入岩体。通过对上述3份样品计算得到的压力-温度（P-T）平衡条件，限定了加拉廷峰地体西北部具有代表性的变质作用环境。上述样品的地质年代学数据也刊载于该《Lithosphere》期刊论文中。

其他说明：作者：Cailey B. Condit、Kevin H. Mahan、Alexis K. Ault与Rebecca M. Flowers；2015年发表于《Lithosphere》的论文《美国蒙大拿州西南部古元古代碰撞造山带深部根部的前陆指向型高级构造作用扩展》，刊载卷期及页码：7(6): 625-645。