The Distribution of Extension with Depth in the Newark Basin: Constraints from Fission-Track Ages

伸展构造过程中大陆岩石圈的裂陷可以通过多种方式完成，包括均匀的岩石圈减薄和伸展不随深度均匀的拆离构造。每个模型预测伸展后不同的沉降历史，这些应反映在裂谷盆地填充物的沉积物中。在裂谷岩石圈冷却过程中，快速沉降阶段之后是一个与收缩有关的较慢的负指数阶段，而如果地表伸展和裂谷与下方未伸展的岩石圈分离，则热阶段减少或不存在。阿巴拉契亚山脉中部三叠纪-侏罗纪时期的纽瓦克盆地现在由沉积物组成，这些沉积物被解释为仅代表最初的快速沉降阶段。尚不清楚热相沉积物是否从未沉积（暗示剥离构造）或沉积但被侵蚀（暗示岩石圈均匀伸展）所移走。该项目将收集和解释来自盆地横断面的碎屑磷灰石裂变径迹年龄，试图确定在白垩纪重叠沉积物沉积之前可能被侵蚀带走的沉积物的最大数量。结果将与现在大西洋的初始分裂和形成的裂谷样式有关，并将提供一个有充分文献记载的大陆尺度伸展的例子，可用于与其他裂谷盆地进行比较。

Rifting of continental lithosphere during extensional tectonics can be accomplished in a variety of ways including uniform lithospheric thinning and detachment tectonics in which extension is not uniform with depth. Each model predicts different subsidence histories subsequent to extension and these should be reflected in the sediments in filling the rift basins. Where rapid subsidence phase is followed by a slower negative exponential phase associated with contraction during cooling of the rifted lithosphere, whereas the thermal phase is reduced or absent if surface extension and rifting is detached from under- lying unextended lithosphere. The Newark Basin of Triassic- Jurassic age in the central Appalachians now consists of sediments interpreted to represent only the initial rapid subsidence phase. It is unclear if thermal phase sediments were never deposited (implying detachment tectonics) or deposited but removed by erosion (implying uniform lithosphere extension). This project will collect and interpret detrital apatite fission-track ages from a transect across the basin in an attempt to determine the maximum amount of sediment that could have been removed by erosion before Cretaceous overlap sediments were deposited. Results will bear on rifting style of the initial breakup and formation of the present Atlantic ocean, and will provide a well- documented example of continental-scale extension that can be used in comparisons to other rift basins.