风成碳酸盐岩的全球分布及其对西沙的启示

风成碳酸盐岩作为一种独特的海岸地貌在全球中纬度地区广泛分布,在全球气候分带上多属于气压带与风带交替控制的地中海气候、热带草原和热带沙漠气候区,与全球气候带的吻合较好。风成碳酸盐岩在各个时代均可发育,但以第四纪更新世风成碳酸盐岩最为常见。风成碳酸盐岩的发育主要受气候背景的影响,还受海岸地貌背景及浅海碳酸盐岩生产力的制约,并与全球海平面变化关系密切,相对而言在海平面高位期发育更好。西沙石岛更新世风成碳酸盐岩是热带海洋季风气候背景下发育起来的少数实例之一,是东亚季风的产物。石岛风成碳酸盐岩的存在可能反映了该区晚更新世相对干旱的气候条件。石岛风成碳酸盐岩与古土壤的旋回变化可能反映了气候背景的干湿变化或海平面的波动,其成因机理的深入揭示对南海西北部东亚季风及古海洋的变化研究具有重要的价值。

GLOBAL DISTRIBUTION OF CARBONATE EOLIANITE IN THE WORLD AND IMPLICATION FOR XISHA ISIANDS

Carbonate eolianite forms distinctive coastal landforms on many mid-latitude continents and islands. The global distribution of carbonate eolianite coincides well with the global climate zones, and it is usually located in Mediterranean climate, tropical grassland and desert zones, where the alternation of atmosphere and wind belt dominates. In principle, carbonate eolianite should occur without time limitation, but most of them formed in Pleistocene. The development of carbonate eolianite is mainly influenced by climate, and limited by coastal landform and carbonate productivity. It has close connection with the fluctuation of global sea level. And most of the Pleistocene carbonate eolianite was formed during high sea level stages. The carbonate eolianite on Shidao Island of Xisha Islands is one of the few examples which developed in tropical-marine-monsoon climate zone. The carbonate eolianite on Shidao Island is the product of the East Asian monsoon, which may reflect relative arid climatic conditions during Late Pleistocene Epoch. The alternation of carbonate eolianite and paleosol may reflect the fluctuation of sea level or climate changes. So, the deep study of mechanics of carbonate eolianite on Shidao Island is of great significance to the researches of East Asian monsoon and paleo-oceanography in the southwest of South China Sea.