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莫哈韦沙漠中部,恺第山东南的睡美地区具厚度大于3km 的巨厚火山岩序列,其喷发时间大约在20百万年以前.重建的板块构造格局表明:加利福尼亚岸外由消减作用带向转换断层的构造转化作用也发生在20m.y.前,因此,在此期间所形成的岩石具有火山活动、张性断裂以及钾质交代作用的记录.火山岩序列由玄武岩至流纹岩熔岩流及凝灰岩所构成,并被大面积的皮斯瑞(Peach Spring)凝灰岩及陆相沉积物所覆盖.皮斯瑞凝灰岩之下的层面一般以10°-50°的角度向南西方向倾斜,并被近直立的北西-南北向断裂所切割。掀斜作用发生在皮斯瑞凝灰岩沉积之前。层面-断层间的关系表明:变形作用并非以其最简单的“掀斜-页状”几何形式出现。除了西部地区外,没有重要的低角度断层出露,因此可能隐伏在地下.所出露的南东向背斜可能是一拖拽褶皱,它与南北向的卢德洛断裂晚中新世期后右行扭动密切相关。皮斯瑞凝灰岩的各下伏层位均不同程度地受到了钾质交代作用的影响,使 K_2O 含量高达13.3%,钾质交代岩的分布规律不甚明显,一般沿北西向断裂分布,尤其是沿北西向含碧玉基质的角砾岩带中发育最好。交代岩中经常发现有钡和锰矿.地质及地球化学条件表明:交代作用通常在较浅的深度(<1或2km)及较低的温度条件(<150℃)下发生,至少在两期不同的脉动活动过程中发生了交代作用,并明显地较皮斯瑞凝灰岩的形成时代要早,其钾元素可能来源于封闭盆地卤水的渗透作用,或者是深部杂岩体氢交代作用的结果。
In the central Mojave Desert, the Sleeping Beauty in southeastern Cathay Mountains has a thick volcanic sequence with a thickness of more than 3 km and its eruption time is about 20 million years ago. The reconstructed plate tectonics indicate that the shore of California is dominated by depletion The tectonic transformation of the conversion fault occurred before 20 m.y. Therefore, the rocks formed during this period have records of volcanic activity, tensile fracture and potassic metasomatism.The sequence of volcanic rocks is from basalt to rhyolite lava flow and Tuff and is covered by a large area of Peach Spring tuff and continental sediments. The layers beneath the Pissarf tuff typically slope west-south at an angle of 10 ° -50 ° and are nearly Upright North West - North-South fault cutting. Tilting occurs before the deposition of the Pissarra tuff. The layer-fault relationship shows that deformation does not occur in its simplest “tilt-page” geometry. Except for the western region, there are no important low-angle faults that may be hidden in the ground. The exposed south-east anticline may be a drag fold, which is associated with the north-south L DeLoLo fault after the late Miocene Right twisting is closely related. All the underlying layers of Pissarra tuff are affected by the metasomatism of K to varying extents. The content of K_2O is as high as 13.3%. The distribution of potassic metasomatism is not obvious. It is generally distributed along the NW fracture, especially It is best developed along the northwestern breccia belt containing jasper. Barrenium and manganese ores are frequently found in petrological rocks, and geologic and geochemical conditions indicate that metasomatism usually occurs at shallower depths (<1 or 2 km) and at lower temperatures (<150 ° C), at least for two periods Which is obviously earlier than the formation of Piscari tuff. The potassium element may originate from the infiltration of brine in the closed basins or from the hydrogeochemical interaction in the deep complex.