Bài giảng Bản đồ và bản đồ địa chất - Chương 4: Không chỉnh hợp - Nguyễn Huỳnh Thông

9/8/2015 1 GEOPET BÀI GIẢNG CHỈ DÀNH CHO SINH VIÊN THEO HỌC LỚP ĐỊA CHẤT KIẾN TRÚC & ĐO VẼ BẢN ĐỒ ĐỊA CHẤT TS. Nguyễn Huỳnh Thông 1 NỘI DUNG Định nghĩa? Phân loại? Ví dụ? 2 9/8/2015 2 Định nghĩa? Unconformity is the contact between sedimentary rocks that are significantly different in age, or between sedimentary rocks and older, eroded igneous or metamorphic rocks. 3 D (Youngest) C B A (Oldest) Unconformity How Unconformities Form? Unconformities happen for two reasons: sediment deposition stopped for a considerable time and/or existing rocks were eroded prior to being covered by younger sediment. 4 9/8/2015 3 Types of Unconformities ? The type of unconformity (in other words, what we call it) is based upon what rock types are involved; whether it is the result of erosion or no deposition; and whether older sedimentary rock layers were tilted prior to being eroded. 5 Phân loại? An angular unconformity is the result of erosion of tilted layers of sedimentary rock. The erosion surface is buried under younger, horizontal layers of sedimentary rock 6 9/8/2015 4 7 A disconformity also involves erosion of sedimentary rocks. But here, the older rock layers were not tilted before they were eroded. In the least obvious case, the disconformity (the erosion surface) is parallel to the layering of both rock layers. Those can be difficult to identify, and usually require dating of the rocks 8 9/8/2015 5 9 10 9/8/2015 6 11 Disconformity ? Angular conformity ? 12 ? Youngest Oldest 9/8/2015 7 13 THANK YOU ! 14 CHUẨN BỊ: • CHƯƠNG 5: DẠNG NẰM CỦA ĐÁ