论文部分内容阅读
对位于渤海湾牡蛎礁平原东部的大吴庄牡蛎礁一个完整剖面的系统14C年代测定与校正表明,该礁体的持续时间约为1600年(7200~5600calBP)。以壳体生长纹层氧、碳同位素获得的礁体平均建造速率1cm/yr来计算礁体的持续时间,结果仅为14C计年历时的三分之一。14C测年与壳体同位素计年结果的对比表明,礁体的每一水平层平均占据了一定的时间(约200年),这一时间段是不适宜礁体正常建造的“缓变型地质环境恶化期”。礁体正常建礁层及水平夹层的时空分布与地区性气候变化曲线对比结果表明,水平夹层与正常建礁层的转换与地区性气温波动相对应。水平夹层代表的“缓变型地质环境恶化期”,对应着地区性气温偏冷时期。
The 14C dating of a complete profile of the Da Wuzhuang oyster reef in the east of the oyster reef plain in the Bohai Bay shows that the duration of the reef is about 1600 years (7200 ~ 5600 calBP). The duration of the reef was calculated from the average construction rate of reefs obtained from the growth of laminae oxygen and carbon isotopes at a rate of 1 cm / yr and the result was only one third of the 14C. A comparison of 14C dating and shell isotopic dating shows that each horizontal layer of the reef occupies an average time (about 200 years), which is a “slowly changing geologic environment not suitable for the normal construction of reefs Deterioration period. ” The comparison of spatial and temporal distributions of normal reefs with horizontal intercalations and regional climate change curves shows that the conversion of horizontal intercalations and normal reefs corresponds to regional temperature fluctuations. Horizontal mezzanine represented “deterioration of geological environment deteriorating period”, corresponding to the regional temperature colder period.