青藏高原西北缘冰川火山作用初步研究

冰川火山作用是指火山活动和冰之间的相互作用，冰川火山喷发物堆积序列可以提供宝贵的古冰川环境信息，在国际上已获得广泛关注，而国内冰川火山的研究还属于空白。本项目将以硫磺达板、克里雅河、奇台达坂、泉水沟等火山区内的第四纪火山为研究对象，开展火山地质地貌调查，查明研究区的冰川火山类型、分布、数量、产状和火山地貌等特征，研究冰川火山喷发岩相特征，恢复喷发序列；开展火山岩石学与岩相学研究，研究熔岩和碎屑喷发物与水作用的微观特征，探讨火山喷发时的冰川和水环境；开展典型样品的年代学系统测试，确定冰川火山喷发时代和活动期次。综合上述冰川火山地质、火山岩石学、岩相学与年代学的研究成果，查明研究区第四纪冰川火山的活动历史，深化对青藏高原西北缘第四纪火山活动的认识与理解。研究成果将填补我国冰川火山学研究领域的空白，为青藏高原西北缘古环境气候的恢复和认识提供来自于火山学研究的证据与约束。

The northwestern Tibetan Plateau is located at the border between the Tibetan Plateau and the Tarim Basin where three major tectonic blocks have been sutured together. The previous studies have shown that extensive volcanism has existed in the northwestern Tibetan area over the past 10Ma, where impressive glacial landforms and successions of Quaternary glacial sediments are abundant throughout the region. It provides us the ideal place to study the volcanic activity within glaciers. Generally, interaction of water and magma has a major effect on the.style of volcanic activity and the morphology of volcanic landforms. Since subglacially-erupted volcanic sequences can provide proxies for studying range of palaeo-ice parameters and they are potentially highly useful archives of palaeoenvironmental information, the laciovolcanism and palaeoenvironmental significance of the Quaternary volcanism in the northwestern Tibetan plateau is a critical issue and deserves great attention. In this proposed study, We will use lithofacies and succession analysis to describe and interpret volcanic outcrops in northwestern Tibetan Plateau, which show evidence for volcanic eruption beneath thin ice. The field work includes mapping different rock units and collecting.series of volcanic rock samples for the further laboratory analysis. In the field, special attention will be paid to define the basic units of the.subglacial/subaqueous volcanic edifices, to describe the most common landforms in details, and to analyze the process of palagonitization and consolidation in subglacial volcanic activity. In the lab, we will analyze the petrographic texture of the rock samples to identifying magma–water interaction from the surface features of volcanic particles. And we will perform measurement and analysis in Ar-Ar isotopic chronology and other dating techniques to determine the timing and evolution history of the volcanic activity. Finally, we will integrate the all evidences from field geology investigation and the lab analysis to construct the regional evolution history of the Quaternary glaciovolcanism in northwestern Tibetan Plateau. Our results will provide useful evidences for interpretations of the lithofacies and sequence architecture of subglacially erupted volcanic successions to deduce simple local and regional glacial histories in northwestern Tibet.