摘要
本文通过对中国、日本海滩岩的分布、类型、成因、时代以及与构造运动、古气候、海平面关系的对比研究,认为日本的海滩岩比中国的偏北8°纬度;海滩岩可分两大类型;主要为海水成因;日本海滩岩的时代可分4个组,中国的可分3个组,日本未见更新世海滩岩;海滩岩发育期与温暖期对应,中全新世气温曾比今高2℃左右;海滩岩对构造运动有良好反映;两国海滩岩所反映的海平面曲线相似,沉积期、胶结期分别与海进期、海退期对应。
The north limits of the beach rock in Xiangshan (29°30′N), Zhejiang Province of China and in Suzu (37°29′N) of Noto Peninsula of Japan have been found, respectively. The former is located at middle subtropical zone while the latter at warm temperate zone. The beach rocks can be divided into two types of intertidal and intense wave zone, and their subtypes is composed of sand, gravel, shell debris and coral reef debris. It is considered that the origin of beach rock is chiefly cemented by calcium carbonate deposits from sea-water but not from underground water and the calcium carbonate is existed in the form of aragonite and Mg-rich calcite. There are some beach rocks of Late Pleistocene and Early Holocene in China but those in Japan are all dated Holocene. According to the ages, the Holocene beach rocks are classified into four groups in Japan: 5000～6500a, 3000～4500a,1000~2000a and 0～500a B. P., and three groups in China: 5300～5800a, 3200～4400a and 0～2500a B.P.. The development periods of beach rock are comparable with the warm climate periods in China or Japan. From the comparison between the north limit of modern beach rock near the Osumi Strait (30°50′N) and that containing the Jomon Pottery in the Naru Island (32°51′N), it is clear that the beach rock is also an index of the Climatic Optimum in Middle Holocene. The beach rock in Xiangshan of China (29°30′ N)in comparison with the modern beach rock of Xisha Island (16°N) shows the temperature in Middle Holocene was 3.5℃ higher than present in China. The sea-level curve described by beach rocks since Middle Holocene in China and that in Japan are similar to each other. The higher sea level (transgression) is consistent with the depositional period of beach materials, whereas the lower sea level (regression) provided a favourable condition for the cementing process of beach rock.
出处
《热带地理》
北大核心
1992年第2期108-121,共14页
Tropical Geography
