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題名 | 荖濃溪斷層作為臺灣南部新、古第三系界限斷層的檢討=On the Laonunghsi Fault--A Boundary Fault between the Paleogene and the Neogene Strata, Southern Taiwan |
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作者 | 林偉雄; | 書刊名 | 經濟部中央地質調查所彙刊 |
卷期 | 12 1999.06[民88.06] |
頁次 | 頁1-24 |
分類號 | 353.4 |
關鍵詞 | 荖濃溪斷層; 土 灣斷層; 潮州斷層; 界限斷層; Laonunghsi fault; Tulungwan fault; Chaochou fault; Boundary fault; |
語文 | 中文(Chinese) |
中文摘要 | 荖濃溪斷層長久以來被認為是臺灣南部板岩帶與西部麓山帶的界限斷層,但是荖濃溪斷層兩側地層岩性近似,因此荖濃溪斷層的延展和位置仍有爭論。為了釐清荖濃溪兩側岩層關係和確定荖濃溪斷層的位置,本研究重新調查荖濃溪中游地區的地質來解決上述問題。研究區域內地層可由下而上分為四層: 禮觀層、梅山層、石內層和六龜礫岩,禮觀層整合伏於梅山層之下,而石內層整合覆於梅山層之上,此外六龜礫岩則西以六龜斷層與石內層接觸,東以土瓏灣斷層與梅山層接觸。全區構造為東北--西南方向,由西而東構造分別為內英山向斜、荖濃溪背斜、唯金溪斷層層、美瓏山斷層、六龜斷層和土瓏灣斷層。荖濃溪斷層並未由土瓏灣斷層位置往北延伸,所謂的「荖濃溪斷層」應是荖濃溪背斜及其背斜軸部為因應體積變化所引致的軸部斷裂。界限斷層的想法源自對沉積岩與變質岩的分層矛盾,由於屈尺斷層、水長流斷層和荖濃溪斷層等一系列以往認為是界限斷層,它們可能都是位移不大的局部性斷層,故應不具廣域的構造意義,基於文獻的回顧檢討,這些斷層的位置延展均需再重新核查定義。 |
英文摘要 | The Laonunghsi Fault has been thought as a boundary fault between the Slate Belt and the Western Foothills Belt of southern Taiwan. However, there are arguments concerning the extent and location of the fault resulting from the similarity of lithologic characteristics of the strata on the either side of the fault. To resolve this problem, it is important to do the geologic mapping along the area where the fault is located. The strata exposed in the study area are as follows in ascending order: the Likuang Formation, the Meishan Formation, the Shihnei Formation and the Liukuei Conglomerate. The Likuang Formation conformably underlies the Meishan Formation, and the Shihnei Formation conformably overlies the Meishan Formation. On the other hand, the Liukuei Conglomerate is adjacent to the Shihnei Formation by the Liukuei Fault to the west, and isnext to the Meishan Formation by the Tulungwan Fault to the east. The structural trend of the studied area is approximately northeast and southwest. The structures from west toeast are as follows: the Neiyinshan Syncline, the Laonunghsi Anticline, the Weichinhsi Fault, the Meilungshan Fault, the Liukuei Fault and the Tulungwan fault. Instead of extending from the northern tips of the Tulungwan Fault, the Laonunghsi Fault is reinterpreted as an anticline structure--the Laonunghsi Anticline. The fracture along the axis of the anticline resulted from the change of the volume during the folding. The idea of boundary fault results from a discrepancy of the classification between the sedimentary rocks and the metamorphic rocks. Therefore, the boundary faults (the Chuchi Fault, the Shuichangliu Fault and the Laonunghsi Fault etc.) between the Paleogen and the Neogene strata are only of local significance without regional tectonic implication. Based on an analysis of the literature reviewed, it is suggested that the location and extent of these faults should be checked again in the field and redefined. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。