川东北类前陆盆地须家河期盆-山耦合和层序充填样式  

Basin-range coupling and sequence filling patterns of the Upper Triassic Xujiahe Formation in the Northeastern Sichuan analogous foreland basin,China

作　　者：翟文亮[1] 郑荣才[1] 朱如凯[2] 戴朝成[1] 高红灿[1] 

机构地区：[1]油气藏地质及开发工程国家重点实验室(成都理工大学),成都610059 [2]中国石油勘探开发研究院油气储层重点实验室,北京100083

出　　处：《成都理工大学学报（自然科学版）》2009年第3期268-275,共8页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：国家重大专项课题“大型油气及煤层气开发”(2008ZX05000-003-01)

摘　　要：根据高分辨率层序界面识别和沉积序列综合分析,将川东北地区上三叠统须家河组划分为2个超长期和5个长期基准面旋回层序。这两个级别的层序演化和充填样式清晰地反映了川东北类前陆盆地晚三叠世须家河期盆-山耦合过程:相当于须二-须三段的"下成盆期",米仓山-大巴山构造山系以低幅隆升为主,川东北地区坳陷幅度小,物源供给与可容纳空间增长率基本持平,以发育辫状河三角洲-湖泊沉积体系为主,具有上升与下降半旋回相域沉积厚度近于相等的对称型层序结构和充填样式,反映相对稳定和均衡的盆-山耦合过程;相当于须四-须六段的"上成盆期",米仓山-大巴山开始进入强烈逆冲推覆和构造隆升阶段,川东北前陆盆地坳陷幅度急剧加大,碎屑物供给量骤然增多且远大于可容纳空间增长率,发育冲积扇-扇三角洲-辫状河三角洲沉积体系,盆内仍以发育上升与下降半旋回相域沉积厚度近于相等的对称型层序结构和充填样式为主,而近造山带的盆缘以发育上升半旋回相域沉积厚度远大于下降半旋回的不完全对称型层序充填样式为主,局部发育仅保留上升半旋回沉积记录的非对称型层序结构和充填样式,反映非均衡盆-山耦合特点。According to the multifactorial analysis of boundary identification in high-resolution sequence and sedimentary sequences, the Upper Triassic Xujiahe Formation（T3x） in Northeast Sichuan are divided into two super-long-term and five long-term base-level cycle sequences. The sequence evolution and sequence filling patterns of the two grades can clearly reflect the coupling process between basin and range of the Upper Triassic Xujiahe Formation in the Northeastern Sichuan foreland basin. The characteristic is that in the lower basin-forming period of T3x2-T3x3, the Micangshan-Dabashan Mountains ridges were in the low amplitude tectonic uplift, the depression amplitude was low in the northeast regions, the material supply and the growth rate of the accommodation space were basically stable, the braided river delta-lake sedimentary system was dominant, and the deposit thickness in the sequence structure of the rising half-cycle and failing half- cycle was mainly in the same symmetry, reflecting the relative stability of strata and the balance of the coupling process between basin and mountain; In the upper basin-forming period of T3x4-T3x6, the Micangshan-Dabashan Mountains began the stage of strongly thrusting-napping and tectonic uplifting, the depression amplitude suddenly enlarged, the supply of clastic sediments suddenly increased and was more than the growth rate of the accommodation space, mainly developed the alluvial fan delta- braided river delta sedimentary system was dominant, the deposit thickness in the sequence structure of the rising half-cycle and {ailing half-cycle and filling patterns were mainly in the same symmetry inside the basin, but in the marginal basin, the non complete symmetry was dominant, in which the thickness of the rising half-cycle was more than that of the falling half-cycle, and in some areas, only the rising half-cycle have been reserved, reflecting the unbalance feature in the coupling process between basin and range.

关 键 词：川东北前陆盆地 上三叠统 须家河组 盆-山耦合 层序充填样式 层序-岩相古地理 

分 类 号：TE121.3[石油与天然气工程—油气勘探]