变质场梯度的用途是什么?- 江南体育网页版- - - - -地球科学堆江南电子竞技平台栈交换 最近30从www.hoelymoley.com 2023 - 07 - 10 - t13:12:32z //www.hoelymoley.com/feeds/question/13262 https://creativecommons.org/licenses/by-sa/4.0/rdf //www.hoelymoley.com/q/13262 6 变质场梯度的用途是什么? 好 //www.hoelymoley.com/users/2570 2018 - 02 - 01 - t15:05:50z 2019 - 07 - 20 - t00:39:42z < p >是我的理解,变质场梯度是PT线跟踪的最高温度点的一系列PTt路径相同的岩石变质事件。< a href = " https://i.stack.imgur.com/LyfSj.png " rel = " noreferrer " > < img src = " https://i.stack.imgur.com/LyfSj.png " alt = "在这里输入图像描述" > < / > < / p > < p >这有用的究竟是什么?似乎并不描述的物理意义,因为美元\ mathrm {T_{马克斯}}识别点美元可以发生在不同的时间,所以并不代表地温梯度在任何固定的快照时间。< / p > //www.hoelymoley.com/questions/13262/-/17517 # 17517 1 答案由Gimelist变质场梯度的用途是什么? Gimelist //www.hoelymoley.com/users/725 2019 - 07 - 20 - t00:39:42z 2019 - 07 - 20 - t00:39:42z < p >你是完全正确的。< a href = " https://doi.org/10.1111/j.1525-1314.1997.00038.x " rel = " nofollow noreferrer " >托德和工程师写< / >:< / p > < blockquote > < p >的岩石矿物的表面躺在一个位点的< em > T p < / em > - < em > < / em >的状况…必须强调…< em >不< / em >意味着p < em > < / em > - < em > T < / em >分布或地热实现在任何时候在这个地区的造山演化。即便< em > P < / em > - < em > T < / em >值反映最大变质条件下,这些都是建立在不同的时间在不同的地区…显示所有的集成效应…即tectonometamorphic流程。埋葬的总和,加热、构造和侵蚀去顶和冷却。< / p > < /引用> < p >,但变质场梯度仍然是有用的,特别是当比较不同的岩石。< / p > < p >每个样品在你的图(A、B和C)是一个单一的岩石和看它告诉你这岩石和岩石的历史。当研究大区域(一个“字段”)会有很多岩石,可能不同于彼此在各自< em > P < / em > - < em > < / em >路径。例如,在一个岩石套件现在蘸90°,有人可能会认为,表面上步行3公里= 1千巴的压力,等于大约3公里的深度。正因为如此,每个样本沿横断面将经历了不同的温度,与理想的更深层次的还热的。< / p > < p >通过选择一个方便的参考点(单个样本的最高温度),沿横断面和连接所有的样本,你可以得到一个估计的< em > T p < / em > - < em > < / em >梯度,可以近似地热(在许多假设)。 The same Todd and Engi paper has this figure:

enter image description here

Each of the lines is based on several dozens of individual samples. Based on this representation of the data, they go on to conclude:

The metamorphic field gradients and age determinations and consistent with two stages of metamorphism. The first stage created the field gradients preserved in the northern part of the field area. The second thermal pulse affected only the south-eastern part of the field area. This occurred at a later time, under lower pressure conditions.

Reaching those conclusions is only possible when condensing the 100 or so individual samples they used (i.e. 100 individual P–T-path loops) to what turned out to be only two metamorphic field gradients.

Todd, C. S. and Engi, M. (1997), Metamorphic field gradients in the Central Alps. Journal of Metamorphic Geology, 15: 513-530. doi:10.1111/j.1525-1314.1997.00038.x
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