Eolian Dispersal Patterns of Zircon and its Subsurface Geochemistry in Continental Weathering Systems

在确认了澳大利亚经典红土风化层中的折衷性质和风成物的存在后，我们请求延长这笔资金，以继续研究大陆风化系统。我们寻求将SHRIMP(灵敏高分辨率离子微探针)独特的微束能力更多地应用于表面工艺研究，重点是锆石的来源、表面传输和就地风化行为，锆石是一种具有无与伦比的实用价值的耐化学和可老化的探路矿物。我们希望确定西澳大利亚构造稳定的伊尔加恩克拉通地区尘埃大小的风化产物和不溶碎屑副矿物的古老风尘扩散模式和矿物学梯度。我们的研究将集中在远离主源区的东侧断面上的一系列未受侵蚀的红土上，我们推测主源区是通过古风尘作用为澳大利亚珀斯附近的贾拉代尔铝土矿贡献了外来锆石。在平扎拉造山带源区700 Ma的Leeuwin地块，对基岩花岗岩、麻粒岩和斜长岩出露的副矿物(锆石、金红石、独居石和钛铁矿)进行了研究，并测定了锆石的年龄。此外，通过对从雨量计阵列收集的当代尘埃样本中的风成锆石进行年龄测定，我们可以确定来源区域是否发生了显著变化。最后，我们希望研究母质锆石就地风化的矿物学和同位素过程，并对自生锐钛矿进行直接SHRIMP测年。我们希望测试它们在表征和计时风化锋推进和碎屑进入地下的生物力学混合速率方面的应用，从而丰富可用于地表过程研究的地质年代学方法。

Having confirmed the eclectic nature and presence of eolian additions in a classical lateritic regolith in Australia, we request renewal of this funding for continued study off continental weathering systems. We seek to make more new applications of unique microbeam capabilities of the SHRIMP (sensitive high-resolution ion microprobe) to surface process studies centering on the provenance, surficial transport and in situ weathering behavior of zircon, a chemically resistant and datable pathfinder mineral of unparalleled utility. We wish to define ancient eolian dispersal patterns and mineralogical gradients of dust-size weathering product and insoluble detrital accessory minerals across the tectonically-stable Yilgarn craton of Western Australia. Our study will focus on sampling a sequence of uneroded laterites in an easterly transect leading away from the principal source region which we infer to have contributed foreign zircon to the Jarrahdale bauxite near Perth Australia by paleo-eolian processes. In the 700 Ma Leeuwin Block of the Pinjarra Orogen source region, we wish to study the accessory mineral suite (zircon, rutile, monazite and ilmenite) in bedrock granite, granulite and anorthosite exposures and date the zircons. Also, by dating eolian zircons in contemporary dust samples collected from rain gauge arrays, we can ascertain if source regions have shifted significantly. Finally, we wish to study the mineralogical and isotopic processes of in situ weathering of parent material zircon and to pursue direct SHRIMP dating of authigenic anatase. We wish to test their use in characterizing and timing the advance of the weathering front and biomechanical admixing rate of detritus into the subsurface thereby augmenting the array of geochronological methods available for surficial process studies.