| 山地冰川沉积相模式与特征 |
| |
| 引用本文： | 崔之久,熊黑钢.山地冰川沉积相模式与特征[J].第四纪研究,1989,9(3):254-268,292. |
| |
| 作者姓名： | 崔之久 熊黑钢 |
| |
| 作者单位： | 北京大学地理系，北京大学地理系 |
| |
| 摘 要： | 山地冰川沉积研究在中国有特殊重要性。因为欧、美对冰碛沉积研究多限于大陆冰盖,沉积环境比较单纯,冰水沉积比重很大,而中国山地冰川多限于山体内部,冰水沉积极不发育,且沉积环境很复杂,亚相变化也大。此外中国山地冰川多属大陆性,与欧、美海洋性冰川在物理性质和沉积特征上都有不同。如冰川磨蚀作用弱,冰碛中粉砂少,冰上融出碛发育而流碛和滞碛不发育,原生(同生)构造如粗糙斜层很发育等。这些都将丰富冰碛沉积学内容,并对科学地鉴别中国东部各种混杂堆积的成因有重要意义。如据现代冰川沉积指标庐山就没有任何冰川堆积。
|
| 关 键 词： | 冰碛沉积 沉积构造 混杂堆积 泥石流沉积 |
THE SEDIMENTARY FACIES MODEL AND CHARACTERISTICS OF MOUNTAIN GLACIER |
| |
| Institution: | Department of Geography, Peking University, Beijing |
| |
| Abstract: | Two excellent sedimentary section of continental mountain glacier exist in the Urumqi-Korla highway and Dushanzi-Kuqa highway crossing Mt. Tianshan. Based on these sections the basic model and moraine types of mountain glacier had been established. Subglacier melt-out till,superglacier melt-out till and flow till occur from lower part to upper part in the same section. Usually there is a rolling interface layer between two layers. They are two types of glacial sediments which has different sedimentary characteristics. Subglacier melt-out till contains certain amount of materials. It is relatively compact due to the glacial pressure. It has complex lithological character and most of them are from upper part of the valley. Erratics have undergone abrasion of glacier and have been rounded. Superglacier melt out-till has less fine material. It is usually loose. and porous. The lithological character is relatively simple. It contains more local materials. The gravels are scarcely abraded and always unfounded.The flow till imbeded in the above two layers are mostly as lens. They are relatively compact due to the high content of fine materials. Lodgement till and deformation till only part appeared in the sediments of mountain glacier. Perhaps the glaciers are so small in somewhere or if the dynamic of glacier are not strong enough. They will develop very well for example in Altay Shan. Usually the lodgement till of mountain glacier become fluted moraineor only appear in the upper side of roches moutonnees. Besides, the glacial-fluvial deposits develop very weak in the sediments of continental mountain glacier. The diamicton of various genesis, for example, tills and debris flow sediments has entirely different sedimentary types and sequence. The disputable diamicton section of Yangjiaoling and Xinqiao in Lushan are quite different from our sedimentary model of mountain glacier and are entirely similar to the sedimentary model of debris flow which are also set up by us. There are several kinds of macro sedimentary structures and micro structures in the sediments of mountain glacier in the protogenic structure, such as large bed structure constituted by superglacier melt out-till of upper part and subglacier melt-out till of lower part. Rough diagonal bedding, particularly developed in superglacier melt-out till. It is formed when the materials move down from the surface of glacial ice onto slope. They always appear as flexures or syncline. The belt structure is formed by the different sources moraine which are transported and deposited along the direction of glacier movement. There are not horizontal exchange between different sediment belts. So they keep the parallel stripes in the sediments. Besides, there are many mass structures, such as flow till mass, bed rock mass which are from glacial bed due to the shear action, and erratic mass which concentrated in the hollow of the glacial surface. The deuterogenie structures are almost pushed by descending glacier, such as push-fold structure, shear fault structure, epigenetic structure and lamina deformation structure. Besides, there are decken structure development in some places where the stress concentrated. All of those mentioned above are quite different from the flow sedimentary structure made by debris flow. These are very important indications for recognization for the genesis of diamicton. |
| |
| Keywords: | |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《第四纪研究》浏览原始摘要信息 |
| 点击此处可从《第四纪研究》下载免费的PDF全文 |
|
