甘肃北山地区古近纪以来古气候变化的遥感信息响应

The Remote Sensing Information Response to the Paleoclimate Change Since Paleogene in Beishan Area,Gansu

在高分辨率和landsat ETM多光谱遥感影像上选择典型的古近纪至第四纪地层剖面,计算Landsat TM遥感影像矿物指数,分别利用氧化铁指数(TM3/TM1)、亚铁指数(TM5/TM4)和粘土化指数(TM5/TM7)来识别Fe3+氧化物、Fe2+氧化物和粘土化的相对富集层,并获得上述指数的图切影像剖面。通过三个典型TM遥感矿物指数剖面的分析,获得了研究区古近纪至第四纪古气候变化信息。渐新世—中上新世气候总体为从极炎热、干湿季节明显的环境逐渐向暖热、干湿季节明显的气候环境演化;更新世为三个旋回的寒冷冰期与间冰期交替。全新世气候为温湿和干冷频繁交替期。通过罗布泊三角洲变迁、湖泊阶地变迁和消亡的遥感解译,全新世及未来的气候总体有向干冷荒漠化方向演变的趋势。

The typical stratigraphic profiles from paleogene, to quaternary are selected in high resolution and land- sat TM multi-spectrum remote sensing image, and mineral indexes are calculated by TM image band ratios. The relative enrichment layers of the Fe3＋ oxide, Fe2＋ oxide and clay are identified according to ferric index （TM3 / TM1 ）, ferrous index （TM5 / TM4） and clay index （TM5 / TM7 ） respectively. Through the analysis of three typical mineral index profiles, the paleoclimate change information from paleogene to quaternary is derived in the study area. From oligocene to pliocene the climate in general varies from extreme hot, distinct dry and wet to warm, distinct dry and wet season. Pleistocene is three cycles of glacial epoch and interglacial epoch alternately. The holocene climate is a frequent alternation period of warm humidity and dry coldness. The remote sensing in- terpretation of the change of delta and lakes terrace migration shows that the holocene and future climate in general has an evolution trend toward a dry and cold desertification