| 海南岛东北部海岸沙丘的沉积构造特征及其发育模式 |
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| 引用本文： | 吴正,吴克刚.海南岛东北部海岸沙丘的沉积构造特征及其发育模式[J].地理学报,1987(2). |
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| 作者姓名： | 吴正 吴克刚 |
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| 作者单位： | 华南师范大学地理系
(吴正)，华南师范大学地理系(吴克刚) |
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| 摘 要： | 海岸沙丘沉积构造中既有大型交错层理,也具某些区别于内陆沙丘构造的特征,如厚层顶积层的保存及变形层理的普遍存在。 本区海岸沙丘形成于东北季风,沙源来自海滩砂。从海滩后滨向陆地的沙丘类型依次是海岸前丘、横向沙丘和新月形沙丘、抛物线沙丘、纵向沙丘、海岸沙席。其中海岸前丘和沙席为海岸沙丘区别于内陆沙丘的特有类型。本区海岸沙丘的发育开始于3000年前。
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| 关 键 词： | 海南岛 海岸沙丘 沉积构造 沙丘海岸 |
SEDIMENTARY STRUCTURE AND DEVELOPING MODEL OF COASTAL DUNES ALONG THE NORTHEASTERN COAST OF HAINAN ISLAND, CHINA |
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| Wu Zheng Wu Kegang.SEDIMENTARY STRUCTURE AND DEVELOPING MODEL OF COASTAL DUNES ALONG THE NORTHEASTERN COAST OF HAINAN ISLAND, CHINA[J].Acta Geographica Sinica,1987(2). |
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| Authors: | Wu Zheng Wu Kegang |
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| Abstract: | Along the northestern coast of Hainan Island, Holocene coastal dunes and dune rock make a wide tropical coastal dune belt.
The sedimentary structure and developing model of coastal dunes are discussed based on morphologic field work, and laboratary research in which the analysing of grain size, scanning of the surface characteristics of quartz sand, identifing of microfossiles, researching of dune-rock cement under the polaring microscope, dating of 14C age are experimented.
The structures are typified by aeolian large cross-bedding with steep (30?35? winddown dipping foreset and gentle (normally less than 10? windward dipping topset. The structures are also typified by special features of coastal dune structure, such as the thick remaining topset.Syngentic sedimentary deformed structures are common.
All conditions of the coastal wind regime, dune-sand resource, and basement topography are advantageous to the development of coastal dune belts. The coastal wind regime coincides with the distribution of dunes and dip of the stratum structure of dunes. All this reveals that the major dynamic source to form, coastal dunes is the Northestern wind that prevails during the dry winter from Sept. to March. And the results of grain size analysis in coastal dune sands are identified neither with the continental dune nor with the littoral sediments. The surface characteristics determined by the electronic microscope scanning of quartz sands are diplogenetic characteristics of both beach and dune. It is proved that the resources of coastal dune sands are beach sands.
There are a few kinds of dunes found along the coast. They are coastal foredunes, transverse dunes, barchan, parabolic dunes, longitudinal dunes, sand sheets and the shadow dunes which are superposed on others. The foredunes and sand sheets are particular types of coastal dunes distinguished from continental dunes. The other types are also different from continental dunes. The developing model of coastal dunes is as follows (from the coast to inland).
According to the angle between the direction of the coastline and the direction of on shore wind, the types of dune may be divided into three types of dune coasts.
The age of 14C dating illustrates that the coastal dunes began to develop 3000 years ago. |
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| Keywords: | : Hainan island coastal dune Sedimentary structure Dune coast |
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