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地震反射资料显示,东南亚利桑那盆岭区晚新生代萨福德盆地是一个深 4.5km、向西北方向延伸、朝西南方向倾斜的半地堑,它由中中新统—上上新统沉积物组成,由一个晚中新世层序界线将其分为下部盆地充填层序和上部盆地充填层序。下部盆地充填沉积期的拉张被看作是顺一东倾的岭盆边界断层进行的,该边界断层包含皮纳利诺山核部复合体东北侧的次生破碎带。这是一条在整个中第三纪和晚新生代活动的铲状滑脱断层,或者说是一个切割滑脱断层或与它合并的年轻断层喇叭。尽管沿反向断层的阶段性运动能短暂地产生对称形地堑,但盆地的大多数拉张还是被看作是盆岭边界断层上的滑动。盆岭边界断层弯曲的上盘运动在盆地充填中产生滚动构造,并影响半地堑内的沉积。下部盆地充填沉积期间,与沉积相关的快速沉降期产生厚的横向延展的湖泊或冲积平原沉积,近源冲积扇沉积局限于盆地边缘。快速拉张和与沉积相关的沉降期,或上部盆地充填沉积开始时盆岭边界断层上段变陡,导致了较大断层弯曲上的一个大下拗。沉积局限在这下拗里,直到它被充填。上部盆地充填沉积期的阶段性沉降造成了广泛的互层状湖泊和河流沉积。盆地西南侧向东北的倾斜和上部盆地充填沉积晚期的沉积中心向东北方向的迁移,提示了与晚期核部上隆相关的拉张速率的降低。
According to the seismic reflection data, the Late Cenozoic Safford Basin in Basin Ridge, Southeast Arizona, is a 4.5 km deep, northwestward, semi-graben slanted to the southwest. It is composed of the Miocene-Upper Pleistocene sediments , Which is divided into a lower basin filling sequence and an upper basin filling sequence by a late Miocene sequence boundary. The pull-out of the lower basin during filling and sedimentation is considered as a succession of the basin boundary fault, which contains secondary crustal zones to the northeast of the Pinarino Mountain core complex. This is a shovel-like slip fault throughout the Tertiary and Late Cenozoic activities, or a young fault horn that cuts or merges with an exfoliative fault. Although the periodic movement along the reverse faulting can produce symmetrical graben for a short time, most of the stretching in the basin is still regarded as a slip on the basin-ridge boundary fault. The upper plate movement with fault curvature at the basin-ridge boundaries produces rolling structures in the basin fill and affects the sedimentation within the semi-graben. During filling and sedimentation in the lower basin, thick laterally extending lakes or alluvial plains are deposited during rapid subsidence associated with sedimentation, and deposition of near-source alluvial fan is confined to the margin of the basin. Rapid pull-ups and sedimentation-related sedimentation periods or steep upper basin-boundary boundary faulting at the beginning of filling-up of the upper basin led to a large downward bend over larger faults. Deposition is limited to this bend until it is filled. The phased subsidence of the upper basin during filling and sedimentation resulted in the widespread deposition of interlayered lakes and rivers. The northeast-easterly dip of the basin and the northeastern migration of the sedimentary center of the late filling-up sedimentation in the upper basin suggest a decrease in tension rate associated with late nuclear uplift.