【摘要】：冷泉碳酸鹽巖是冷泉滲漏活動(dòng)的重要產(chǎn)物之一,它記錄了冷泉流體的來(lái)源、其活動(dòng)演化特征和沉積環(huán)境等。通過(guò)對(duì)南海北部東沙海域Site3站位采集的三個(gè)煙囪狀冷泉碳酸鹽巖的礦物成分、碳氧同位素及碳酸鹽巖中黃鐵礦硫同位素的研究,確定了冷泉滲漏可能的流體來(lái)源,結(jié)合煙囪狀碳酸鹽巖獨(dú)特的形貌特征,探討了研究區(qū)冷泉流體的活動(dòng)演化特征。煙囪A為環(huán)狀,外環(huán)直徑16 cm,中央流體通道直徑5 cm;煙囪B呈底部直徑8 cm的實(shí)心錐形;煙囪C也為環(huán)狀,外環(huán)直徑20 cm,中央流體通道直徑12 cm。三個(gè)煙囪都具有較負(fù)的碳同位素組成(δ~(13)CVPDB值低至 55.7‰)和較正的氧同位素組成(δ~(18)OVPDB值高達(dá)5.4‰)特征。研究認(rèn)為,甲烷是該海域冷泉滲漏流體的主要烴類(lèi)來(lái)源,其中沉淀煙囪C的冷泉流體中很可能存在水合物分解釋放流體的加入。三個(gè)煙囪狀碳酸鹽巖的外層相比于內(nèi)層,普遍具有δ~(13)C值高、δ~(18)O值低、δ~(34)S值高的特征,認(rèn)為這是由于煙囪狀碳酸鹽巖從外至內(nèi)形成過(guò)程中沉積空間逐漸受到限制導(dǎo)致流體滲漏強(qiáng)度增強(qiáng)而造成的。綜上所述,煙囪狀冷泉碳酸鹽巖因其獨(dú)特的形態(tài)結(jié)構(gòu),是冷泉流體滲漏特征在時(shí)間和空間上變化的優(yōu)良記錄者。
[Abstract]:Cold spring carbonate rock is one of the important products of cold spring leakage. It records the source of cold spring fluid, its activity evolution characteristics and sedimentary environment. Based on the study of mineral composition, carbon and oxygen isotopes and pyrite sulfur isotopes in three chimneys cold spring carbonate rocks collected at Site3 station in Dongsha sea area, northern South China Sea, the possible fluid sources of cold spring leakage have been determined. Based on the unique morphologies of chimney-shaped carbonate rocks, the active evolution characteristics of cold spring fluids in the study area are discussed. Chimney A is annular, outer ring diameter 16 cm, central fluid channel diameter 5 cm; chimney B is solid cone with bottom diameter 8 cm, chimney C is also annular, outer ring diameter 20 cm, central fluid channel diameter 12 cm. All three chimneys have negative carbon isotopic composition (未 ~ (13) CVPDB value as low as 鈮，

本文編號(hào)：2472862