柴达木盆地西南地区古近纪—新近纪断裂坡折带与沉积相分布*

综合地震反射时间突变、岩石类型与沉积微相和地层厚度等多种方法来识别断裂坡折带，并通过构造平衡剖面恢复的方法对所识别的断裂坡折带进行进一步确定，认为柴达木盆地西南地区在古近纪和新近纪发育了七个泉、红柳泉、阿拉尔、阿拉尔东、Ⅷ号、昆北和Ⅺ号断裂坡折带。由于青藏高原隆升的远程效应，柴达木盆地西南地区断裂坡折带可以分为萌芽期和繁盛期2个发展期，分别对应于古近纪和新近纪，且断裂坡折带活动强度依次增强。依据断裂坡折带发育部位及对沉积相分布控制作用的不同，可将断裂坡折带划分为浅水坡折带和深水坡折带：浅水坡折带之上发育辫状河相和三角洲平原亚相；深水坡折带之下发育深水重力流沉积；两者之间以三角洲前缘和滩坝亚相为主，是目前油气勘探的重点。Ⅺ号断裂坡折带中部以下地区具备形成深水浊积的条件，极有可能是岩性油气藏勘探的接替区。

Fault slope-break zone and sedimentary facies distribution of the Paleogene-Neogene in southwestern Qaidam Basin

It has been determined that Qigequan，Hongliuquan，Alaer，East Alaer，Ⅷ，Kunbei and Ⅺ fault slope-break zones developed during the Paleogene and Neogene by distinguishing the slope-break on geological and seismic profiles，recognizing the slope-break zones on contour map and identifying the true palaeo-fault slope-break on structural balance profiles，with a series of comprehensive means，including T0，petrology，microfacies and strata thickness.The vertical development of fault slope-break zones can be divided into the embryotic stage(Paleogene)and the flourishing stage(Neogene)due to long distance effects of Tibet Plateau uplifting.The slope-break zones in shallow water controlled braided rivers and delta plain.Gravity flows may develop below the deep water slope-break zones.The sedimentary facies between those two belts are delta front and beach & bar which are the main exploration fields at present.The area below Ⅺ fault slope-break belt has the condition to develop deep-water turbidite and even might be the replacing for lithologic hydrocarbon reservoirs.