闽粤沿海老红砂多期沉积地层的发现及其意义  

Finding and its Significance of !Old Red Sand" Strata with Multiple Depositional Stages on the Coasts of Fujian and Guangdong

作　　者：吴正[1] 王为[1] 

机构地区：[1]华南师范大学地理系,广东广州510631

出　　处：《中国沙漠》2001年第4期328-332,共5页Journal of Desert Research

基　　金：国家自然科学基金项目 ( 4 96 710 12 )资助

摘　　要：对广泛分布于闽粤沿海的老红砂进行了全面的野外调查 ,调查发现在福建的平潭青峰、晋江科任和广东的惠来靖海资深园、徐闻锦和东门下等地的老红砂沉积地层 ,存在多期沉积。热释光 (TL)、电子自旋共振 (ESR)测年表明 ,它们是晚更新世中、晚期末次冰期 (玉木冰期 )的沉积 ,并可分出 6 8～ 42ka和 30～ 10ka两个相对较集中的沉积期。在这两期中 ,又以 30～ 10ka左右的晚玉木冰期 (Q3 3 )的老红砂发育规模最大、分布最广 ,这显然与晚玉木冰期 (盛冰期 )时的气候更干冷、冬季风的风力更强劲 ,风沙活动更强烈有密切关系。The !old red sand' is widely distributed on the coasts of Fujian and Guangdong. In recent years,we investigated in detail the !old red sand' in the field. The sections of the !old red sand' found at many localities on the coasts of Fujian and Guangdong are composed of many layers alternating tighten sand with loose sand, red color with yellow color and coarser grains with finer grains. The boundary between the upper cemented red layer with finer grains and lower half-cemented yellow layer with coarser grains is not apparent in the sections. The red color changes gradually downward into yellow one. However, the interface between the base of the yellow layer and the underlying red one can be clearly identified and some times forms step landforms in the field. This interface represents a break in the depositional process of the !old red sand', indicating existence of multi stages of the process. Dating of thermoluminescence (TL) and electron spin resonance (ESR) denote that the !old red sand' is the deposits in middle and later stages of late Pleistoncene time. Two depositional periods of 68～42 ka and 30～10 ka can be classified and the later is the time of the later Würm glacier. The !old red sand' in the period of 30～10 ka developed on the largest scale and had the widest distribution induced by dryer and colder climate, more powerful winter monsoons and stronger aeolian activities. Such environment in the later Würm glacier period can also be shown by the depositional ratio being calculated from the sections of the !old red sand'. The ratio of the lower part in the sections is 2^2 cm5ka+{-1} while that in the upper part is 3^8 cm5ka+{-1}, indicating a quicker depositional ratio in later Würm period than that in early Würm period.

关 键 词：老红砂 多期沉积 玉木冰期 福建 广东 风沙活动 沉积地层 细砂沉积物 

分 类 号：P931.3[天文地球—自然地理学] P512.2