The Kinematic Significance of Folds in the Paleoproterozoic Foxe Fold Belt, Melville Peninsula, Nunavut, Canada

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。首席研究员将利用褶皱铰链旋转的数值模拟结果来阐明加拿大努纳武特地区福克斯褶皱带（FFB）的构造历史。褶皱铰链和相关构造的方位为构造域过去的相对运动提供了宝贵的信息。这些结构随着应变的增加而发展和旋转，它们的旋转路径可以通过数值模拟来预测。该数值模型将在Melville半岛的岩石上进行试验，在构造地质和矿产勘查中具有广泛的应用前景。研究人员还将通过放射性测年技术来确定变形的年龄。该项目是与加拿大地质调查局（GSC）和其他大学的科学家合作进行的。波士顿学院的两名硕士生将参加这个多学科项目，并获得在偏远地区和尖端实验室工作的宝贵经验。当地的努纳武特因纽特人学生将被GSC雇用到该领域，作为加拿大能源和矿产地理测绘（GEM）计划的一部分，该计划旨在为努纳武特的因纽特人社区提供经济和培训机会。因纽特学生将直接与PI在实地工作。e - e走向的古基底由太古宙基底和上覆、内覆的古元古代岩石组成。研究人员将研究变形的运动学，古元古代和太古代岩石之间的接触，以及区域太古代省边界，其中许多是在哥伦比亚超大陆组装期间活跃的。梅尔维尔半岛的FFB结构先前被解释为主要基于鞘层褶皱铰链线向WSW转移。然而，巴芬岛的结果表明了相反的运输方向，这构成了两个假设的数值测试的基础。如果WSW传输是正确的，那么FFB相邻部分的倾斜传输方向问题仍然没有解决。如果相反，线状构造的WSW走向可以用平行于带走向的伸展或其他构造上似是而非的情况来解释。这两种假设将通过实地和实验室显微镜对褶皱几何形状和剪切织物的研究进行检验。此外，通过U-Pb离子探针和U-Th-Pb电子探针技术，横切关系和褶皱的年龄以及剪切带的运动学将受到限制，这可以精确地确定附属矿物的年代，特别是在薄片中。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The principal investigator will use results from numerical modeling of the rotation of fold hinges to elucidate the tectonic history of the Foxe Fold Belt (FFB) in Nunavut, Canada. Orientations of fold hinges and related structures yield invaluable information about past relative movements of tectonic domains. These structures develop and rotate with increasing strain and their rotation paths can be predicted by numerical modeling. The numerical models, which may have wide application in structural geology and mineral exploration, will be tested on the rocks of the Melville Peninsula. The investigators will also constrain the ages of deformation by radiometric dating techniques. The project is in collaboration with the Geological Survey of Canada (GSC) and scientists from other universities. Two Masters students at Boston College will take part in this multidisciplinary project and gain invaluable experience working in remote field areas and cutting-edge laboratories. Local Nunavut Inuit students will be employed in the field by the GSC as part of the Canadian Geo-mapping for Energy and Minerals (GEM) program, which is designed to provide economic and training opportunities to the Inuit community in Nunavut. An Inuit student will work directly with the PI in the field.The ENE-trending FFB comprises Archean basement with overlying and infolded Paleoproterozoic rocks. The investigators will study the kinematics of the deformation, the contacts between the Paleoproterozoic and Archean rocks, as well as regional Archean province boundaries, many of which were active during assembly of the supercontinent Columbia. FFB structures in Melville Peninsula have previously been interpreted as indicating transport to the WSW, based primarily on sheath fold hinge lines. However, results from Baffin Island indicate an opposed direction of transport, and this forms the basis for the numerical testing of two hypotheses. If WSW transport is correct, the issue of oblique transport directions in adjacent segments of the FFB remains unresolved. If the opposite is true, the WSW trend of linear structures may be explained by, for example, extension parallel to the trend of the belt, or other tectonically plausible scenarios. The two hypotheses will be tested through field and laboratory microscopy studies of fold geometries and shear fabrics. In addition, crosscutting relationships and the age of the folds and kinematics of the shear zones will be constrained through U-Pb ion-probe and U-Th-Pb electron-probe techniques, which allow for accurate dating of accessory minerals, particularly in thin-section.