地理学报
地理學報
지이학보
ACTA GEOGRAPHICA SINICA
2001年
1期
83-91
,共9页
闫满存%王光谦%李保生%董光荣
閆滿存%王光謙%李保生%董光榮
염만존%왕광겸%리보생%동광영
巴丹吉林沙漠%高大沙山%形成发育%更新世%古风系
巴丹吉林沙漠%高大沙山%形成髮育%更新世%古風繫
파단길림사막%고대사산%형성발육%경신세%고풍계
通过对巴丹吉林沙漠高大沙山的考察,以及沙丘形态和风况、沙山TL测年、古沙丘层理产状等的研究表明,高大沙山的形成发育受沙源、风系、底基地形和灌草植被等因素的影响。第四纪以来弱水古水系的变迁为沙漠及沙山的发育提供了丰富的沙物质来源。沙山发育的受西风和西北风两大盛行风系的控制,末次冰期以前为西风环流主导时期,地表盛行风向为西风,次为西北风;末次冰期以来为季风环流主导时期,地表盛行风向为西北风,次为西风。沙山底基地形的起伏不仅诱发近地表气流产生波状运动,同时也是风沙流运行的障碍。气候湿润期发育的沙丘灌草植被通过抑制风蚀、扑捉风沙等作用加速沙山的发育。高大沙山是新月形沙丘和沙丘链、复合新月形沙丘或沙丘链演进而形成的大型稳定风积床面形态。
通過對巴丹吉林沙漠高大沙山的攷察,以及沙丘形態和風況、沙山TL測年、古沙丘層理產狀等的研究錶明,高大沙山的形成髮育受沙源、風繫、底基地形和灌草植被等因素的影響。第四紀以來弱水古水繫的變遷為沙漠及沙山的髮育提供瞭豐富的沙物質來源。沙山髮育的受西風和西北風兩大盛行風繫的控製,末次冰期以前為西風環流主導時期,地錶盛行風嚮為西風,次為西北風;末次冰期以來為季風環流主導時期,地錶盛行風嚮為西北風,次為西風。沙山底基地形的起伏不僅誘髮近地錶氣流產生波狀運動,同時也是風沙流運行的障礙。氣候濕潤期髮育的沙丘灌草植被通過抑製風蝕、撲捉風沙等作用加速沙山的髮育。高大沙山是新月形沙丘和沙丘鏈、複閤新月形沙丘或沙丘鏈縯進而形成的大型穩定風積床麵形態。
통과대파단길림사막고대사산적고찰,이급사구형태화풍황、사산TL측년、고사구층리산상등적연구표명,고대사산적형성발육수사원、풍계、저기지형화관초식피등인소적영향。제사기이래약수고수계적변천위사막급사산적발육제공료봉부적사물질래원。사산발육적수서풍화서북풍량대성행풍계적공제,말차빙기이전위서풍배류주도시기,지표성행풍향위서풍,차위서북풍;말차빙기이래위계풍배류주도시기,지표성행풍향위서북풍,차위서풍。사산저기지형적기복불부유발근지표기유산생파상운동,동시야시풍사류운행적장애。기후습윤기발육적사구관초식피통과억제풍식、복착풍사등작용가속사산적발육。고대사산시신월형사구화사구련、복합신월형사구혹사구련연진이형성적대형은정풍적상면형태。
High megadunes in the Badain Jaran desert, with a height rangingfrom 200 to 300 m in general and maximum height of 500 m or more are seldom seen in the other sand seas of the world. Up to present no much work associated with the formation and growth of high megadunes have been done. On-the-spot investigations of the Badain Jaran desert and a series of research work, including sand dune types and their spatial features, megadunes strata and TL dating, palaeowind direction measurement and modern wind data analysis, indicate that the formation and growth of high megadunes in the Badain Jaran desert are controlled by sand source, pre vailing wind patterns, underlying relief of megadunes and vegetation on sand dun es. Ruoshui system developed in the western and northwestern Badain Jaran area w as a main sand source for the formation and growth of high megadunes. Dips from fossil sand dunes cross-bedding and steep-face orientations in three locaties distributed in the Badain Jaran desert demonstrate that the prevailing palaeowind patterns over the Badain Jaran desert are at variance throughout the Quaternar y period. Before last glaciations westerly winds originating from westerly circu lation predominated but that there were also important northwestly winds from East Asian monsoon circulation at the time of high megadune growth. Since last glaciations, northwestly winds have dominated the area but accompanied also with the relatively important westerly winds in the processes of megadune growth. Simul taneously, the initial stages of the magedunes are related to the wave-like air flow motion caused by the intimidation from underlying hilly relief which become an obstacle against moving wind blown sand. The shrub and grass on sand dunes, fed by rainfall during stronger summer monsoon, encourages the growth and development of megadunes by trapping and accumulating upwind windblown sand and combating wind erosion as well as promoting roughness over dune surface. Intergrated aeolian bedforms in the area went through a temporal development process from ba rchans, barchanic ridges, compound barchans, megabarchans to high megadunes sinc e the Quaternary.