鲁西中生代幔枝构造及其金矿化

文章在收集岩石学、岩石化学、同位素地质学、构造地质学和地球物理学等资料的基础上，采用多学科相结合、相互验证和综合分析的方法，论述了鲁西中生代地质特征和金矿床形成的关系。研究表明：鲁西地区中生代为典型的幔枝构造，它是华北地幔亚热柱的次级构造单元。鲁西幔枝构造由核部岩浆-变质杂岩、外围盖层拆离滑脱层和上叠构造断陷-火山盆地3个单元组成。在上叠构造断陷-火山盆地单元内，广泛分布幔源岩浆岩，包括中基性到碱性的侵入岩、富钾火山岩和煌斑岩；同时，由于幔枝构造的上隆，形成了与之相配套的放射状和环状断裂体系。结合前人中生代岩浆活动的年龄数据，提出了鲁西中生代幔枝构造的活动经历了早侏罗世和早白垩世2个高潮期。按照构造控矿的特征，鲁西幔枝构造中的金矿床可分为韧性剪切带型和外围拆离滑脱层型两种。

Mesozoic Mantle_branch Structure and Related Gold Deposits in Western Shandong

Viewed from mantle_plume, this paper discusses characteristics of regional geolo gy and related gold deposits in western Shandong. It is proved that Luxi (wester n Shandong) area was a typical mantle_branch structure in Mesozoic, which was co mposed of three units, i.e., igneous_metamorphic complex, surrounding detachment _slip layers and overlapped fault volcanic basin. In the overlapped fault volcan ic basin there occurred extensive magmatic rock consisting of potassium_rich int ermediate_basic to alkaline volcanic rocks and lamprophyre. Due to the uplifting of the mantle_branch structure, radial and ringed faults were formed. According to the isotopic age data, it is held that the activities of Mesozoic mantle_bra nch structure in western Shandong experienced two climax periods: one is Early J urassic ranging from 188 Ma to 190 Ma, wherase the other is Early Cretaceous ran ging from 110 Ma to 130 Ma, with the latter being more extensive. According to c haracteristics of the ore_control structure, The gold deposits related to this s tructure might be divided into two types, i.e. the ductile shear zone type and t he detachment_slip layer type, with the gold deposits of the latter type being m ore important.