[퇴적암]
기존 암석이 잘게 부서진 것을 퇴적물이라 하고, 퇴적물이 쌓여서 굳은 암석을 퇴적암이라고 한다. 퇴적물은 주로 흐르는 물에 의해 이동하다가 흐름의 속도가 느려지는 곳에 쌓인다. 이 후 지하 깊이 묻혀 딱딱한 암석이 된다. 퇴적암은 구성입자의 크기에 따라 역암, 사암, 이암으로 분류된다.
[층리]
암석이 층을 이루며 쌓인 것을 층리라고 한다. 층리는 퇴적암의 가장 큰 특징 중 하나이며 퇴적 당시의 환경을 말해준다.
[로그방법]
- 자암의 암석은 중생대 백악기의 경상분지에서 형성된 화강암이다. (진실/오류)
- 암석이 절벽을 이루는 경우, 대개 단층과 절리를 따라 암석이 쪼개져 떨어져 나가는 작용이 큰 역할을 한다. (진실/오류)
- 캐시 좌표에서 만암자암절벽의 맨 오른쪽 끝까지는 약 몇 미터 떨어져 있습니까?
a) 20m
b) 70m
c) 120m
- 만암자암절벽의 가장 특징적인 지질특성은 층리를 찾기 어려울 정도로 수없이 많은 절리(joint)가 발달하는 것이다. (진실, 오류)
- 캐시존을 배경으로 GPS를 든 캐셔 또는 GPS의 사진을 로그에 올려주세요. (선택사항)
*답을 제 Profile에 있는 메시지창을 이용해 제게 보내주세요. 이제 로그하셔도 됩니다. 답에 문제가 있을 경우 제가 메시지를 드리겠습니다.
**[English]**
[Mananjaam Cliff]
Jaam means a red rock and it is also called as a red cliff.
Rock of Jaam is a sedimentary rock, which has been formed at Gyeongsang basin in the Mesozoic Cretaceous Era. Stratigraphically, it belongs to the upper Iljig stratum. (Jang, Kihong, et al, 1978) However, as it is marked as Jeomgok stratum in the geological map prepared by the Korea Institute of Geoscience and Mineral Resources (Hwang, Jaeha, et al, 1996), its stratigraphical location is not clear. Rock that is composed of Jaam is a medium or coarse textured arenite, and it shows relatively a fair sorting. It does not show any sedimentary structure inside the rock. The most special geological characteristic is the development of many joints as much as it is difficult to find stratiform. Joints of high angle (70°~85°) close to vertical line have been developed most clearly. Its directions are northwest-southeast(N20°W, N45°W), northeast-southwest(N25°E), and east-west. (Picture III-97, 98) Joints of low angle have been developed toward east-west tilting about 30°. Rock of Jaam is a sedimentary rock, which was deposited on the ground surface in Mesozoic Cretaceous Era (about 120 million years ago). As any sedimentary structure has not been left, it is not possible to know under what condition it was deposited, but when it is judged on the basis of surrounding sedimentary stratum, it seems that it was deposited under the environment of streams. After the sedimentation, while the earth's crust slowly sunk below, thick sedimentary stratum piled above it. Sediments buried deep in underground became hard rocks. After this, the crust was uplifted above and rocks deep in the underground came up to the ground surface. Rocks that had come up to the ground surface went through weathering and corrosion for a long period. They were broken along the joints and cut by the stream to remain as a today's beautiful cliff. When rocks form a cliff, splitting away of rocks along the faults and joints plays a great role.
[Sedimentary rocks]
The particles of rocks fragmented by weathering and erosion are sediments. Sedimentary rocks are formed by deposition and lithification of sediments. Sediments are mainly transported by water flows and deposited in the places where the flows slow down. After deposition, sediments are buried deep to form hard sedimentary rocks. Sedimentary rocks are classified into conglomerate, sandstone, and mudstone based on the size of sediment grains.
[Stratification]
Stratification means a stratigraphic series of rocks that have been deposited. It is one of the most distinct features and shows the former environment when it was formed.
[How to log]
- Rock of Jaam is a granite, which has been formed at Gyeongsang basin in the Mesozoic Cretaceous Era. (True/False)
- When rocks form a cliff, splitting away of rocks along the faults and joints plays a great role. (True/False)
- How far is the rightmost end of the Mananjaam Cliff from the publicised coords?
a) 20m
b) 70m
c) 120m
- Mananjaam Cliff's most special geological characteristic is the development of many joints as much as it is difficult to find stratiform. (True/False)
- Upload the photo of you or your GPS with the cache zone in the background! (The task is optional)
* Please send the answers to me by message on my profile! You may log as 'Found'. If the answer is not correct, I will contact you.