运用钻井岩心、测井及层序地层学的有关理论、方法,对位于扬子地块西缘、四川攀枝花地区的宝鼎盆地的含煤岩系进行了层序地层学与聚煤作用研究。在主要含煤段大荞地组发育12个层序界面和11个四级层序,其中在40#煤层以上地层发育层序Ⅳ到层序Ⅺ等8个四级层序。伴随着宝鼎盆地由断陷盆地(大荞地组沉积时期)向大型拗陷盆地(宝鼎组沉积时期)演化,盆地基底沉降速率减小,可容空间增加速率降低,聚煤作用在垂向上先增强再减弱。断陷盆地发育早期,聚煤作用较弱;断陷盆地发展中期(层序Ⅳ-层序Ⅷ),主要煤层多发育于低位体系域、初始湖泛面附近和高位体系域中晚期,平面上聚煤中心位于可容空间增加速率中等的三角洲平原相带;至盆地发展晚期(层序Ⅸ-层序Ⅺ),主要煤层的发育位置逐渐向四级层序最大湖泛面靠近,平面上聚煤中心向可容空间增加速率最大的盆地沉积中心迁移。
Well logs, outcrops and the principles of the sequence stratigraphy have been used to reconstruct sequence stratigraphic framework and to predict the coal distribution of the Upper Triassic coal measures in the Baoding Basin of western Yangtze platform ( Sichuan Province). A total of 12 sequence boundaries and 11 fourth-order sequences have been identified in the succession above the No. 40 coal seam within the Daqiaodi Formation. With the evolution of the basin from a faulting basin to a large-scaled depressional basin, the rate of basin subsidence, thus the rate of new accommodation creation, was slo- wing down gradually and the coal accumulation had a tendency of strengthening first and then weakening. During the early stage of the faulting basin, the coal accumulation was less evident and was restricted in a limited area. During the intermediate stage of the faulting basin (sequences Ⅳ - Ⅷ) , coal seams were mainly formed in the LST, near the initial transgressive surface, and in the mid-late HST. The coal accumulation center was mostly located in the delta plain setting where a moderate rate of new accommodation creation was maintained. During the late stage of the faulting basin (sequences Ⅸ -Ⅺ) , the main coal seams were located in the late TST and early HST, both close to the maximum flooding surface. The coal accumulation center migrated to the depositional center of the basin where the highest rate of new accommodation creation was kept.