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通过鄂尔多斯盆地8.00Ma以来红粘土时空分布特征分析,红粘土沉积的地貌位置、与下覆地层接触关系、粒度特征分析,研究红粘土形成过程及环境背景:中新世晚期—上新世,鄂尔多斯地块已完成由盆地向高原转型,其明显的环境效应在地貌上表现为差异隆升造成的起伏地表,形成遭受风蚀的高地与接收红色粘土沉积的洼地.红粘土序列物质主要来源是风力携带的粉尘,以“覆盖式”披盖在原始地貌上.但是,降落在高地的粉尘在风力与水流作用下被搬运至洼地,不能象第四纪黄土粉尘那样沉降后基本覆盖在整个黄土高原,因此鄂尔多斯地区没有形成连续的红土高原,仅在当时的洼地保留有红粘土沉积.虽然在隆起高地没能保存红粘土,但由于红粘土断续分布在现今黄土高原地区,仍可认为在中新世晚期—上新世,有不连续的“红土高原”存在,红粘土在一定程度上修饰和改造了原始地貌.高原内部出现差异抬升,表现在北部白于山、中部子午岭以及南部渭北北山隆升.渭北北山北缘凹陷形成更早,成为红粘土沉积中心,朝那、灵台、旬邑地区都沉积了相对较厚的红粘土.第四纪以来高原北部干旱化加剧,黄土堆积加速形成黄土高原,晚更新世以来高原加速隆升侵蚀加剧,特别是造成了三门湖被切穿,侵蚀基准面降低,导致地下潜水面降低、河网密度加大、蒸发量增加,从而加剧了黄土高原地区干旱化的发展.因此鄂尔多斯高原隆升对区域环境产生巨大影响.
Through the analysis of temporal and spatial distribution of red clay in Ordos Basin since 8.00Ma, the location of red clay sediments, the contact with underlying strata and the grain size analysis, the formation process of red clay and its environmental background are studied: Late Miocene-Pliocene, Ordos The massif has completed the transformation from the basin to the plateau, and its obvious environmental effect is characterized by the ups and downs of landform caused by the difference uplift, the formation of the highland subject to wind erosion and the depression receiving the red clay deposition.The main source of red clay sequence material is wind-borne However, the dust falling in the highlands is transported to the depressions under the effect of the wind and water flow, and can not basically cover the entire loess as sediments of Quaternary loess dust Plateau, therefore, there is no continuous plateau in the Ordos, and only red clay deposits remain in the depressions at that time.Although the red clay can not be preserved in the uplifted highlands, the distribution of red clay in the Loess Plateau can be considered as Late Miocene - Pliocene, there are discontinuous “Red Plateau ” exists, the red clay to a certain extent, modification and change And the original landform appeared in the plateau, with the elevation uplifted in the interior of Baiyu Mountain in the north, the Ziwu Ridge in the central part and the upwelling of Beishan in the north of Weibei.The earliest depression in the north margin of Beishan Beiwei Formation became the center of red clay deposition, Since the Quaternary period, the aridification of the northern plateau intensified, the loess accumulation accelerated the formation of the Loess Plateau, and the erosion of the plateau accelerated uplift since the late Pleistocene, especially caused the Sanmen Lake to be cut through , The erosion datum is lower, resulting in the decrease of underground diving surface, the increased density of river network and the increase of evaporation, which aggravate the development of aridification in the Loess Plateau, so the uplift of the Ordos Plateau has a huge impact on the regional environment.