MỘT SỐ KẾT QUẢ NGHIÊN CỨU PHÂN BỐ SÒ, ĐIỆP KHU VỰC NGHỆ AN

Some results of placura and granosa shells distribution in Nghe An region On the basis of placura placenta-arca granosa shells investigation in Quynh Van, Dien Chau and Nghi Tien, some new results can be made as the following: - Banks of placura placenta-arca granosa shells in Quynh Van and Nghi Tien; deep-seated in Quynh Nghia, Dien Chau and along Nghi Yen seashore have the time of 4000-4600 yr. - The appearance of the placura placenta-arca granosa shells banks have not either the sources from marine transgression in Holocene, tectonic movement or artificial. - It is possible that those are the deposits of the natural geological activities courses to the seashore in the time of 4000-4600 yr ago.