REU: New Methods for Analysis of Geobarometric Data from Tilted Plutons, with Application to Discordant PaleomagneticPoles from the Coast Plutonic Complex

与变形沉积岩的古地磁数据不同，花岗岩岩体的古地磁矢量数据通常是健壮且簇状良好的。然而，由于在大多数岩体中没有古水平参考面（如层状岩石中的层理），它们在构造重建中的应用受到严重限制，因为任何提出的纬度平移都可以很容易地用岩体的原位倾斜来解释。这种模糊性导致了一场关于太平洋西北地区的第三纪岩体是起源于加利福尼亚巴哈附近，然后向北移动到现在的位置，还是在现在的位置附近形成然后倾斜的重大争论。本项目将考察其中一个岩体，并使用一种广泛适用的压力指示器（角闪石中的铝）来计算该岩体的古水平面。成功的结果不仅将解决“Baja-BC”争议，而且更重要的是将证明获得一般岩体的古水平参考平面的潜力。

Paleomagnetic vector data from granite plutons are commonly robust and well-clustered, unlike paleomagnetic data from deformed sedimentary rocks. However, because no paleohorizontal references plane (such as bedding in layered rocks) is available in most plutons, their use in tectonic reconstructions has been severely limited because any proposed latitudinal translation can just as easily be explained by in situ tilting of the pluton. This ambiguity has led to a major controversy concerning whether or not some Tertiary plutons in the pacific northwest originated near Baja, California and subsequently moved north to their present position, or formed near their present position and were then tilted. This project will examine one of these plutons and use a widely-applicable pressure indicator (Aluminum in hornblende) to calculate a paleohorizontal plane for the pluton. Successful results will not only provide a resolution of the "Baja-BC" controversy, but more importantly would demonstrate the potential to obtain paleohorizontal reference planes for plutons in general.