RUI: U-Pb Zircon Geochronology of Adirondack Metamorphosed Igneous Rocks

以前NSF支持的研究已经提供了超过25个 锆石U-Pb年龄提供了重要的时间框架- 研究阿迪朗达克山脉的地质演化 之间 这些新的结果至少有两个需要进一步的领域， 化学调查 第一批~1300 Ma的玄武质岩石 在南部和东部的阿迪朗达克山脉暴露， calcalkaline趋势 这些岩石和相关的花岗岩 片麻岩，表明存在早期碰撞岩浆 弧 在阿迪朗达克低地海德学校片麻岩~1300 Ma年龄也表现出calcalkaline趋势， 早期碰撞岩浆弧 这两个假设的弧相关 在安置之前， 1160 - 1130 Ma锰硅质-镁橄榄石岩套 两个区域。 建议化学研究是至关重要的 格伦维尔省的板块构造演化 在 此外，海德的侵入与变质火山的历史 学校片麻岩将通过野外和化学方法进行调查。 此外，还建议开展涉及化学物质的研究， 分异趋势的模拟可应用于超镁铁质 在戴安娜情结和詹金斯山的堤坝和床单。在 玛茜·沃尔夫 前者为1154 ± 3Ma的横切正长岩 后者携带1147 = 6Ma的镁橄榄石捕虏体 斯塔克套房将有助于限制目前不确定的上层年龄 斜长岩侵位

Previous NSF-supported research has made available over 25 U-Pb zircon ages that have provided an important temporal frame- work for the geological evolution of the Adirondacks. Among these new results are at least two that require further field and chemical investigation. The first ~1300 Ma mettonalitic rocks exposed in the southern and eastern Adirondakcs and exhibiting calcalkaline trends. These rocks, and associated granitic gneiss, suggest the presence of an early collisional magmatic arc. Within the Adirondack Lowlands Hyde School Gneiss of ~1300 Ma age also exhibits calcalkaline trends and perhaps a second early collisional magmatic arc. These two postulated arc-related terranes docked against one another prior to the emplacement of the 1160-1130 Ma mangeritic-charnockitic suite which traverses both regions. It is proposed that chemical studies be critical to the plate tectonic evolution of the Grenville Province. In addition, the intrusive vs. metavolcanic history of the Hyde School Gneiss is to be investigated by field and chemical means. It is also proposed that chemical studies involving the modelling of differentiation trends be applied to ultramafic dikes and sheets in the Diana Complex and on Jenkins Mt. in the Marcy massif. The former crosscuts syenite dated at 1154+3 Ma and the latter carries xenoliths of mangerite from the 1147=6 Ma Stark suite will help constrain the currently uncertain upper age of anorthosite emplacement.