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

大陆岩石圈在伸展构造过程中的裂谷作用可以通过多种方式完成，包括均匀的岩石圈减薄和伸展深度不均匀的滑脱构造。每个模型都预测了伸展后不同的沉降史，这些都应该反映在充填裂谷盆地的沉积物中。快速下沉阶段之后是一个较慢的负指数阶段，伴随着裂隙岩石圈冷却过程中的收缩，而如果地表伸展和裂谷从下方未伸展的岩石圈中分离出来，则热相减少或消失。位于阿巴拉契亚山脉中部的纽瓦克盆地的三叠纪-侏罗纪时代现在由沉积物组成，被解释为只代表了最初的快速下沉阶段。目前尚不清楚热相沉积物是否从未沉积(暗示拆离构造)或沉积但被侵蚀带走(暗示岩石圈均匀伸展)。该项目将收集和解释横跨盆地的一条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，可能被侵蚀清除的最大沉淀量。这些结果将与现今大西洋最初解体和形成的裂谷样式有关，并将提供一个有充分证据的大陆规模伸展的例子，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.