Collaborative Research: Intracontinental Deformation and Surface Uplift: Geodynamic Evolution of the Hangay Dome, Mongolia, Central Asia

大的相对高海拔、低起伏的表面在大陆上很常见。这种隆起通过影响排水网络和沉积物供应而对地质记录产生重大影响，通过改变大气环流而对气候产生重大影响，并对生物地理和生物群产生重大影响。地球动力学方面的研究表明，这种隆起相当于地幔动力学的一个明显标志。因此，它们提供了一种方法来区分关于大陆岩石圈和更深的地幔如何通过导致大陆内部隆起和质量转移的过程相互作用的假说。蒙古中部的汉盖穹顶为研究这些过程和确定地幔上涌、镁铁质底侵、岩石圈下沉或岩柱活动在多大程度上是其抬升的重要因素提供了一个很好的、可进入的实验室。这项为期五年的项目建议利用汉盖穹顶作为这样一个实验室，协调对岩石层和地幔的结构和状态以及地表隆起和地貌演化史的研究。该项目将涉及利用宽带地震学、玄武岩和捕虏体岩石学和地球化学、40Ar/39Argeronology、稳定同位素和泡状玄武岩古高度学、地貌学和10Be年代学、不同鱼类种群的分子遗传学以及U-Th/He和4He/3He热年代学进行的观测和测量。汉盖穹顶-S在过去30 Ma期间在广泛海拔范围内喷发的玄武岩熔岩的广泛暴露，将是整合所有这些数据的关键。玄武岩的年代测定将使有关玄武岩成因和汉盖-穹顶地幔性质的岩石学数据与使用熔岩作为记录地貌演变和地表抬升历史的时间标志的研究联系起来。

Large relatively high-elevation surfaces with low relief are common onthe continents. Such uplifts have a significant impact on the geological record by influencing drainage networks and sediment supply, on climate by modifyingatmospheric circulation, and on biogeography and the biota. Work in geodynamics hasshown that such uplifts amount to a telling signature of mantle dynamics. Thus, theyprovide a means to discriminate among hypotheses about how the continental lithosphereand the deeper mantle interact through processes that result in uplift and mass transfer incontinental interiors. The Hangay Dome in central Mongolia provides an excellent andaccessible laboratory to investigate these processes and determine the degree to whichmantle upwelling, mafic underplating, lithospheric foundering or plume activity havebeen important agents in its uplift. This five-year project proposes to use the HangayDome as such a laboratory to coordinate studies of both the structure and state of thelithosphere and the sublithospheric mantle as well as the history of surface uplift andlandscape evolution. The project will involve observations and measurements made usingbroadband seismology, basalt and xenolith petrology and geochemistry, 40Ar/39Argeochronology, stable-isotope and vesicular-basalt paleoaltimetry, geomorphology and10Be geochronology, molecular genetics of divergent fish populations, and U-Th/He and4He/3He thermochronology. The Hangay Dome?s widespread exposures of basaltic lavas,which were erupted over the past 30 Ma across a broad range of elevations, will be key tothe integration of all these data. Dating of the basalts will enable linkage of petrologic databearing on basalt genesis and the nature of the Hangay-Dome mantle with studies thatuse the lavas as time markers for documenting landscape evolution and the history ofsurface uplift.