Evolution of Miocene Fluvial Environments in Northern Pakistan

对巴基斯坦北部波特瓦尔高原中新世Siwalik矿床进行了详细的沉积学研究。将从古河道和泛滥平原的几何和水力学、湖水化学、古土壤性质、动植物活动分布、河流改道和沉积速率等方面重建在时间和空间上变化的河流古环境。这些特征的变化将与局部、区域和/或全球控制有关，包括气候、构造作用和沉积物供应。然后，就有可能了解陆地生物在14年至7日期间与物理化学环境变化有关的一个重要的演化期。Siwalik矿床为实现这些目标提供了一个无与伦比的机会，因为：1)3000米厚的地层具有良好的3-D曝光率；2)以前对岩石地层学、脊椎动物古生物学和古地磁测年的研究；3)利用沉积盆地以外地区现有的地质资料对气候变化和构造活动的独立制约。了解河流沉积(包括它们所包含的化石)随构造作用和气候的演化，对世界各地所有年龄的岩石都有意义。这种认识具有经济意义，因为河流矿床通常是水、石油和天然气的储集层，也是煤、金、铀和建筑材料的来源。

A detailed sedimentological study of the Miocene Siwalik deposits of the Potwar Plateau in northern Pakistan is proposed. Temporally and spatially varying fluvial paleoenvironments will be reconstructed in terms of paleochannel and floodplain geometry and hydraulics, chemistry of lacustrine waters, nature of paleosols, distribution of animal and plant activity, river diversions, and deposition rates. Changes in these characters will be related to local, regional and/or global controls including climate, tectonism, and sediment supply. It will then be possible to understand an important period of evolution of land organisms in relation to changes in the physical and chemical environment over a period between 14 and 7 my B.P. The Siwalik deposits offer an unparalleled opportunity to realise these objectives because of: 1) excellent 3-D exposures of 3000 m + of strata; 2) previous studies of lithostratigraphy, vertebrate paleontology, and paleomagnetic age-dating; 3) independent constraints on climatic change and tectonic activity using geologic data now available for areas outside the depositional basin. Understanding of the evolution of fluival deposits (including the fossils they contain) in response to tectonism and climate has implications for rocks of all ages worldwide. Such knowledge has economic implications because fluival deposits are commonly reservoirs for water, oil, and gas, also are sources of coal, gold, uranium, and building materials.