• 作者： 陳民本;謝凱旋
• 作者服務機構： 國立臺灣大學海洋研究所; 中央地質調?所
• 中文摘要： 在南海的巽他陸棚到深海平原上選擇了三十九個活塞岩心的項部來研究其中所含現生超微化石的含量、種數及種類 。有三十八種，亞種或群鈣質超微化石從研究的沉積物中鑑定出來。 有三個因素影響南海現生超微化石群集的分佈。它們是非鈣質陸源物質的稀釋，分泌碳酸?的球菌藻的生?率，以 及沉積中或沉積後球石片的化學溶解。在巽他陸棚上，由於附近島嶼所帶來陸源物質的稀釋，使得球石片不能保存得很 好。其種數隨水深的增加而增多。在礁灘複合區，大量的球石片也顯示出種類的繁多。在南沙群島和中沙群島附近其種 類最多。深海平原上沉積物?的現生超微化石群集顯示出在三千公尺深的中國海盆中有逐漸的溶蝕現象，這群集也指出 溶蝕始自於二千三百公尺處。在深海平原上保存好的超微化石係被濁流或崩移所帶來的。 超微化石的群集中最大群的是Gephyrocapsa oceanica其次?Emiliania huxleyi。複合及次要種的種數指數並沒有什麼關係，但是這些種數招數與含量最多之種的相對含量有很好的反比關係。
• 英文摘要： Abundance, diversity and species composition of recent nannofossil assemblages are described from thirty nine piston core top samples collected from the continental shelf (Sunda shelf), bank-shoal complex and abyssal plain in the South China Sea. In total, thirty eight calcareous nannofossil species, subspecies or groups are identified from the studied sediments. Three factors influencing the distribution of recent nannofossil assemblages in the South China Sea are dilution by noncalcareous terrigenous sediment, productivity of carbonate-secreting coccolithophorids and chemical dissolution of coccolith during and after deposition. On the Sunda shelf, the coccoliths can not be well-preserved due to dilution by terrigenous material discharged from the adjacent islands. The diversity indices increase as the sea water depth increases. Abundant coccoliths in the bank-shoal complex area represent a highly diverse nannofossil assemblage. The highest diversity indices are located near the Nan-Sha Islands and Macclesfield Banks. Recent nannofossil assemblages on the abyssal plain indicate a progressive dissolution feature in the deep China Basin with water depth mostly below 3000 meters. The assemblages also indicate that the lysocline probably exists at 2300 meters. The well preserved nannofossil specimens were transported and deposited on the abyssal plain by turbidity current or slumping. Gephyrocapsa Oceanica is the largest group and Emiliania huxleyi is the second largest in the nannofossil assemblages. The dominant and subordinate species diversity indices do not show any relationship. But these diversity indices are well correlated in reverse ratio with species dominance.
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