2008-01-302024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/671883摘要：台灣西南海域在非常短之距離即有活動大陸邊緣（active margin）與被動大陸邊緣地區（passive margin），此二種大陸邊緣區域皆是天然氣水合物形成之良好環境，國際已有相當多之研究，但是像台灣西南海域此二種環境皆存在之條件卻是非常少見。過去四年在中央地質調查所的資助下，本團隊已有長足之進步，對二種地質構造截然不同之環境，做了初步之探討。雖然已經發現天然氣水合物存在之種種地質、地化、生物現象，但是對於為何存在種種差異卻未能充分瞭解，更無法評估判斷究竟何種環境與區域是最佳之天然氣水合物儲積區域。本計畫植基於過去四年之成果，重新整合團隊，並期能針對此二種環境之氣體組成、微生物、間隙水、自生碳酸岩、特殊大型底棲生物、自生硫化礦物、地質時序與沉積物基本性質等，作整體性分區分年調查。研究團隊包括： (I) 台灣西南海域海水與沈積物之氣體化學組成—楊燦堯教授 (II) 台灣西南海域地質微生物(細菌與太古生物)多樣性調查與天然氣水合物形成與分解 機制探討—賴美津教授 (III) 台灣西南海域自生性碳酸鹽及硫物種之變化與天然氣水合物賦存之關係—林曉武 教授 (IV) 台灣西南海域冷泉地區大型生物群聚之調查研究—陳天任教授 (V) 台灣西南海域天然氣水合物探勘熱區之黏土與自生礦物研究—江威德教授 (VI) 台灣西南海域天然氣水合物潛能區沈積物之地質學特徵—黃奇瑜教授 (VII) 台灣西南海域沉積物基本性質與天然氣水合物賦存之關係—陳汝勤教授 本計畫擬探討天然氣水合物，其氣體在沉積物內之擴散與噴發及受微生物產生之生地化變化，與註記於自生碳酸岩與硫化礦物等之特徵，並探討其沉積年代與噴發擴散時間，來瞭解天然氣水合物在台灣西南海域活動大陸邊緣增積岩體之前、中、後段與被動大陸邊緣二環境之形成與積蓄，並藉著沉積物之基本性質來評估天然氣水合物之經濟價值。 雖然台灣西南海域有著特殊之天然氣水合物蓄積環境，但是台灣過去對相關之研究基礎與硬體建設投資卻相當地薄弱。有鑑於此，本計畫擬添購基本採樣與研究設備。本年度擬申購水下定位系統，俾能將水下觀測之特殊天然氣水合物相關地質地化與生物群落之確實位置，予以定位，方便隨後之採樣與探討此區域之天然氣水合物之特殊蓄積環境。 本計畫亦擬與國外研究單位進行合作，希望能藉助國外先進單位之研究船隻與設備（如ROV, In-Situ Mass Spectrometry, Laser Raman Spectrometry與MD超長岩心等)，探討表層與深層之天然氣水合物存在環境與控制因素，期能於未來四年內評估台灣西南海域之天然氣水合物之儲量、生地化變化與建立未來鑽探之基礎資料。 <br> Abstract: The existence of both passive and active margin adjacent to each other is very unique in the marine environment, especially in evaluating formation of gas hydrate under different tectonic settings. South China Sea adjacent to Taiwan provides such a rare opportunity in studying and comparing gas hydrate formation, migration and sea floor phenomena at both active and passive margin environments. Extensive samplings during the past four years in the Taiwan gas hydrate research program facilitate our basic understandings toward gas hydrate formation and subsequent bio-geochemical processes. Typical phenomena, e.g. gas plume, chemosynthetic community, anomaly pyrite and authigenic carbonate formation, chimney and chemoherm buildup, demonstrate that abundant gas hydrate exist under the sea floor in the South China Sea adjacent to Taiwan. However, little is known about how and when gas migration occurs and nature of subsequent microbial activities and other geochemical processes that may alter the gas hydrate formation and migration in both active and passive margin in these areas. Furthermore, findings of hydrothermal chemo-communities in the cold seep environment further raise the question of how gas and fluid migration and subsequent chemical processes may generate such an unusual chemosynthetic community. In order to understand gas hydrate formation in these two environments and to understand the cause and effect of gas hydrate migration, we have re-grouped related PIs in the field. We intend to study gas composition, microbial process and subsequent pore water variations, authigenic minerals formation, sedimentation and stratigraphy and timing of carbonate formation, and sediment properties. Our group includes: (I) T. F. Yang: Studies on the gas compositions in sea water and sediments offshore southwestern Taiwan. (II) M.-C. Lai: Geomicrobial diversity in the gas hydrate potentials regions offshore southwestern Taiwan and its role in gas hydrate formation and degradation (III) S. Lin: Authigenic carbonate formation and sulfur cycle in the active and passive margin offshore southwestern Taiwan. (IV) T.-Y. Chan: Studies on the gas hydrate megafauna communities offshore southwestern Taiwan (V) W.-T. Jiang: Clay- and authigenic-mineral studies of the favorable sites for gas hydrate exploration offshore southwestern Taiwan (VI) C.-Y. Huang: Geological characteristics of the gas hydrate potential regions offshore southwestern Taiwan (VII) J.-C. Chen: The relationship between sediment properties and the occurrence of gas hydrate offshore southwestern Taiwan Our program, however, will be limited by the lack of advance instruments in conducting sea floor observations and sampling. In addition to our own study program, we intend to collaborate with international research institutions with advance instruments to speed up Taiwan gas hydrate research. Instruments, such as Laser Raman Spectrometry, In-Situ Mass Spectrometry, ROV and giant piston core, will be our main targets. Our goals are to understand the settings and environments for gas hydrate formation and to facilitate a better evaluation for a future drilling program.天然氣水合物活動大陸邊緣被動大陸邊緣冷泉冒氣微生物化學自營性生物自生性碳酸岩黃鐵礦流體移棲gas hydrateactive marginpassive margincold seepventmicrobialchemosynthetic communityauthigenic carbonatepyritefluid migration