张宣隆起核部的转枝莲辉石闪长岩

The Zhuanzhilian pyroxene diorite in core of Zhang-Xuan upwarp.

位于冀西北张家口-宣化地区的转枝莲辉石闪长岩侵入水泉沟正长岩杂岩体中。该岩石由紫苏辉石、次透辉石、黑云母、中长石、正长石以及磷灰石、钛铁矿等副矿物组成。全岩分析结果SiO_253％～59％。本文根据上述两点将其命名为辉石闪长岩,通过岩石成因、稀土元素分布模式和岩石的Sr-Nd同位素组成研究,认为岩体是上地幔和下地壳物质部分熔融的产物,辉石闪长岩的Rb-Sr等时线年龄为143Ma。

The Zhuanzhilian pyroxene diorite is found in Zhangjiakou-Xuanhua area, northwest of Hebei Province. It intrudes into the Shuiquangou syenite complex and consists of hypersthene, salite, biotite, andesine, orthoclase and accessory minerals such as apatite and ilmenite. Bulk-rock analysis indicated that 53% similar to 59% of its composition is SiO2. We categorized it as pyroxene diorite according to petrologic principles. Studies on petrogenesis, REE patterns, and Sr-Nd isotopic composition of the rock suggest that the rock mass comes from partial melting of the the materials originated from in the lower crust and upper mantle. Age of the pyroxene diorite is 143Ma according to Rb-Sr isochron dating.