By shallow seismic prospecting, the Cenozoic Group in the sea area near the Yangtze River Mouth can be divided into five seismic sequences. They correspond to the Quaternary, Pliocene, Upper Miocene, Lower Miocene and...By shallow seismic prospecting, the Cenozoic Group in the sea area near the Yangtze River Mouth can be divided into five seismic sequences. They correspond to the Quaternary, Pliocene, Upper Miocene, Lower Miocene and Eocene respectively. The Quaternary System covers all the detecting area. The Tertiary System overlaps and thins out from NE to SW. The sedimentary basement mainly consists of volcanic rock (J 3) and acidic rock (r 3 5). Paleogene or Late Cretaceous basins are not found there. The faults that have been detected are all normal faults. They can be divided into three groups (NE, NW, near EW) by their trend. The NE and NW trending faults are predominant, and agree with aeromagnetic anomaly. Their length and displacement are larger than that of the EW trending faults. The activity of the NE trending faults is different in different segments. The SW segment is a Quaternary fault, the middle segment is a Neogene fault, The NE is Paleogene. But the segment of the NW trending fault is not obvious. The average vertical displacement rate is about 0 015mm/a.展开更多
文摘By shallow seismic prospecting, the Cenozoic Group in the sea area near the Yangtze River Mouth can be divided into five seismic sequences. They correspond to the Quaternary, Pliocene, Upper Miocene, Lower Miocene and Eocene respectively. The Quaternary System covers all the detecting area. The Tertiary System overlaps and thins out from NE to SW. The sedimentary basement mainly consists of volcanic rock (J 3) and acidic rock (r 3 5). Paleogene or Late Cretaceous basins are not found there. The faults that have been detected are all normal faults. They can be divided into three groups (NE, NW, near EW) by their trend. The NE and NW trending faults are predominant, and agree with aeromagnetic anomaly. Their length and displacement are larger than that of the EW trending faults. The activity of the NE trending faults is different in different segments. The SW segment is a Quaternary fault, the middle segment is a Neogene fault, The NE is Paleogene. But the segment of the NW trending fault is not obvious. The average vertical displacement rate is about 0 015mm/a.
