西南极布兰斯菲尔德海峡PC10孔硅藻氧同位素记录及其沉积学意义

对采自西南极布兰斯菲尔德海峡ＰＣ１０孔的５１个硅藻样品进行了氧同位素分析，结果揭示，柱状样氧同位素曲线可划分为５期，记录了区内近１１２．５ｋａ来的沉积，包括了一个冰期／间冰期旋回和一个冰后期。间冰期的沉积速率高于冰期，推测这与间冰期（暖期）筏冰物质及生物硅质源的供应较冰期（冷期）更丰富所致。

SILICA OXYGEN ISOTOPE OF DIATOM FROM CORE PC 10 IN THE BRANSFIELD STRAIT,ANTARCTICA

Fiftyone diatom samples taken from the piston core PC10 in the Bransfield Strait of West Antarctica were engaged in oxygen isotope analysis. Among them 49 samples yielded relatively good results and 2 samples showed unsatisfied results due to insufficient diatom for analysis need.The δ 18 O values of 49 samples range from 35.32 to 24.30‰(SMOW).Not only the values are systematically lower,but also the spread in δ 18 O is larger than those for late Quaterary diatom reported by other researchers. It is most likely that they were caused by a slightly higher zeolite,quartz and albite in parts of sample identified by X ray diffraction analysis. However the comprehensive study on sedimentary proxies,especially on the correlation analysis between δ 18 O values and diatom (amorphous) contents show evidentially that the impurities within samples have not changed essentially the information of ecological environment reflected by δ 18 O values. The diatom based recults reveal that the 753cm long sediments of core PC10 printed the deposition of this area during the last 112.5 kaB.P.,representing oxygen isotope stages 1-5 and including one incomplete glacial/interglacial cycle and postglacial period. The sedimentary rate in interglacials seem a little higher than that in glacial,owing to the more terrigenous supply by ice rafting during the interglacial stages.