Địa chất kiến trúc và đo vẽ bản đồ địa chất - Chương 4: Không chỉnh hợp

Nội dung text: Địa chất kiến trúc và đo vẽ bản đồ địa chất - Chương 4: Không chỉnh hợp

1. 9/8/2015 GEOPET TS. Nguyễn Huỳnh Thông BÀI GIẢNG CHỈ DÀNH CHO SINH VIÊN THEO HỌC LỚP ĐỊA CHẤT KIẾN TRÚC & ĐO VẼ BẢN ĐỒ ĐỊA CHẤT 1 NỘI DUNG Định nghĩa? Phân loại? Ví dụ? 2 1
2. 9/8/2015 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. D (Youngest) C Unconformity B A (Oldest) 3 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 2
3. 9/8/2015 Phân loại? 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 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 3
4. 9/8/2015 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 4
5. 9/8/2015 9 10 5
6. 9/8/2015 Disconformity ? Angular conformity ? 11 Youngest ? Oldest 12 6
7. 9/8/2015 13 CHUẨN BỊ: • CHƯƠNG 5: DẠNG NẰM CỦA ĐÁ THANK YOU ! 14 7