造山带隆升与非均衡沉降盆地的响应关系——以鄂尔多斯盆地陇东地区长7—长6油层组为例

以鄂尔多斯盆地陇东地区长7—长6油层组为例，通过露头剖面观测、岩心观察及锆石U-Pb测年数据，分析秦岭造山带的隆升特征及对物源的影响、长7—长6油层组内发育的凝灰岩夹层、重力流及震积岩等事件沉积体的时空分布，揭示造山带隆升与事件沉积体之间的响应关系。秦岭造山带自东向西“剪刀式”的俯冲闭合是导致盆地沉积中心不断迁移的动力，长7期在湖盆西南部形成最大深坳区。西秦岭隆升伴生的侵入型“S型花岗岩”为西南部深坳区提供了充足的物质来源。深坳区内部广泛分布着事件沉积体，其中凝灰岩夹层与西秦岭的侵入型岩浆岩具有同源性，自南向北厚度逐渐减薄；深坳区西南部坡折带发育浊流及部分砂质碎屑流沉积体，东北部发育砂质碎屑流及部分浊流、泥质碎屑流沉积体；由盆地西南—东北方向，震积岩岩心变形频率、幅度、规模逐渐降低，表明震源来自于西秦岭附近。因此，秦岭造山带隆升与鄂尔多斯盆地的非均衡沉降及事件沉积响应特征具有很好的时空耦合关系。 

Relationship between orogenic belt uplift and non-equilibrium subsidence basins: a case study of Chang 7 and Chang 6 oil reservoirs in Longdong area,Ordos Basin

The influence the Qinling Orogenic Belt uplift on provenance to the Chang 7 and Chang 6 oil reservoirs in the Longdong area of the Ordos Basin was analyzed. Outcrop and core observation and zircon U-Pb dating were used to characterize the temporal and spatial distributions of deposits such as tuff interlayers, gravity flows and seismites. The relationship between orogenic belt uplift and deposits were discussed. The "scissor-like" subduction closure of the Qinling Orogenic Belt from east to west was the driving force for the continuous migration of the depositional center of the basin, and the largest deep depression was formed in the southwestern part of the lake basin during the Chang 7 period. The intrusive "S-type granite" associated with the uplift of the Western Qinling provided a material source for the deep depression area in the southwest. Deposits are widely distributed in the deep depression area, among which the tuff interlayer is homologous to the intrusive magmatic rocks of the West Qinling, and the thickness gradually decreases from south to north. Turbidity current and some sandy clastic flow deposits were developed in the southwestern slope break belt of the deep depression area, while sandy clastic flow and some turbidity flow and argillaceous clastic flow deposits developed in the northeastern part of the depression area. From the southwest to the northeast of the basin, the deformation frequency, magnitude and scale of seismic core gradually decreased, indicating that the source is from the vicinity of the West Qinling. Therefore, the uplift of the Qinling Orogenic Belt has a good spatio-temporal coupling relationship with the non-equilibrium settlement and sedimentary response characteristics of the Ordos Basin.