摘要：

通过岩心观察、录测井资料分析，并结合区域地质资料，对达尔其地区下白垩统腾格尔组4个砂层组的沉积特征及沉积相平面分布进行了深入研究。结果表明，腾格尔组沉积时期达尔其地区整体处于水进时期，主要发育辫状河三角洲、湖泊和浊积相3种沉积相类型。从凹陷边缘至中心，由辫状河三角洲、滨浅湖逐渐变为半深湖—深湖沉积；自下而上，辫状河三角洲沉积范围逐渐缩小，湖泊沉积规模逐渐增大。浊积相分布在腾格尔组Ⅵ砂层组达17井附近。在薄片和重矿物资料的基础上，通过观察碎屑组分并计算其相对百分含量、分析重矿物稳定系数和ZTR指数变化规律，认为达尔其地区沉积物来自赛呼都格凸起方向，具有短距离搬运和快速堆积的沉积特点；根据同一井在不同井段砂岩成分成熟度的不同，判断沉积物具有多旋回、阵发性的沉积特点；由岩屑类型及重矿物组合特征推断达尔其地区母岩岩性为中基性岩浆岩、沉积岩和变质岩。

Abstract:

Sedimentary characteristics and the planar distribution of sedimentary facies of four intervals of the Tenggeer Formation were investigated based on  core observation， well logging data and regional information in Daerqi area. The researches show that during the deposition of the Tenggeer Formation， braidedfluvial delta， lacustrine and turbidite facies were deposited in Daerqi area. From the margin to the center of the sag， the sedimentary environments gradually changed from braidedfluvial delta， shoreshallow lacustrine to semideep and deep lacustrine settings. During the deposition of the Tenggeer Formation， transgression occurred in Daerqi area. Vertically， braidedfluvial delta and lacustrine deposits were prograded. Turbidite facies was deposited near Well Da 17 in interval Ⅵ of the Tenggeer Formation. Based on the analyses of thin sections and heavy mineral data， the clastic components were observed and the relative content were calculated. The heavy mineral coefficients of stability and changing patterns of the ZTR index were analyzed. The results indicated that the provenance of Daerqi area was from the Saihuduge uplift and was characterized by a shortdistance transportation and quick accumulation. The compositional maturities were different at different depths of the same well. It is concluded that the sediments were deposited multicyclically and spasmodically. Based on the types of clastics and heavy mineral associations， the parent rocks of Daerqi area are of  three types: intermediate and basic magmatic rocks， sedimentary rocks and metamorphic rocks.