Heat flow in the Oregon Cascade Range and its correlation with regional gravity, Curie point depths, and geology
Heat flow in the Oregon Cascade Range and its correlation with regional gravity, Curie point depths, and geology
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俄勒冈喀斯喀特山脉的热流及其与区域重力、居里点深度和地质的相关性
DOI：
10.1029/jb095ib12p19475
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发表时间：
1990
影响因子：
--
通讯作者：
G. Black
中科院分区：
文献类型：
--
作者：
D. Blackwell;J. L. Steele;Michael K. Frohme;Charles F. Murphey;G. Priest;G. Black
给出并讨论了俄勒冈梯级带的新的热流数据。文中描述了几口深井(深达2500米)的热流测量结果，以及布莱滕布什和圣地亚姆山口-贝尔克纳普/弗利地区工业勘探工作的大量新数据。区域热流模式与前面讨论的类似。热流在高级联范围内约为10 0 mW m−2，在西部级联山脉东缘，俯冲带外弧块以西约4 0~5 0 mW m−2。在高热流区，由于岩石的高渗透性和由此产生的快速地下水流动，年轻火山岩的浅层热流较低。在200-400米的深度以下，该地区的大部分地区似乎主要是传导热传递，深度至少为2-2.5公里。温泉附近的区域热流存在扰动，其数值高达背景值的两倍。梯级范围内的重力场具有与热流模式密切相关的特征。这种关系可能是因果关系，为了更详细地检查这种关系，早期的二维建模被扩展到三维。考虑地壳中层密度异常的影响，例如可能与至少有部分熔融区域有关的区域，有两个主要后果。首先，解释了西级联范围/高阶级联范围边界附近的高频重力梯度。其次，与高级联山脉北半部相关的负重力异常可以消除，结果是，与蓝山北缘相关的显著的东北/西南走向区域布格重力异常在整个喀斯特山脉变得连续，克拉马斯山脉北侧也有类似的特征。显然，该带是一个主要的地壳特征，其上叠加了与高热流重合的负重力异常。总结了高/西级联山脉的热流、居里点深度、重力场、地壳电阻率、地壳地震速度和地质之间的相关性或缺乏相关性。许多数据显示了可以根据喀斯喀特山脉中地壳可能的高温进行解释的方面。在华盛顿和不列颠哥伦比亚省的喀斯喀特山脉，中地壳具有异常高的温度，并包含一个深度为10±2公里的岩浆舞台带，该带也可以以柔和的形式被识别出来。
New heat flow data for the Oregon Cascade Range are presented and discussed. Heat flow measurements from several deep wells (up to 2500 m deep), as well as extensive new data from industry exploration efforts in the Breitenbush and the Santiam Pass-Belknap/Foley areas are described. The regional heat flow pattern is similar to that discussed previously. The heat flow is about 100 mW m−2 in the High Cascade Range and at the eastern edge of the Western Cascade Range, It is about 40–50 mW m−2 to the west in the outer arc block of the subduction zone. In the high heat flow zone the heat flow is low at shallow depths in young volcanic rocks due to the high permeability of the rocks and the resultant rapid groundwater flow. Below a depth of 200–400 m much of the area appears to be dominated by conductive heat transfer at least to 2–2.5 km depth. There are perturbations to the regional heat flow in the vicinity of the hot springs where values are up to twice the background. The gravity field in the Cascade Range has characteristics that can be closely related to the heat flow pattern. The relationship may be causal, and to examine the relationship in more detail, earlier two-dimensional modeling is extended to three dimensions. Consideration of the effects of a midcrustal density anomaly, such as might be associated with a region with at least areas of partial melt, has two major consequences. The first of these is that a high-frequency gravity gradient near the Western Cascade Range/High Cascade Range boundary is explained. Second, the negative gravity anomaly associated with the north half of the High Cascade Range can be removed, and as a result, the prominent northeast/southwest striking regional Bouguer gravity anomaly associated with the north edge of the Blue Mountains becomes continuous across the Cascade Range with a similar feature along the north side of the Klamath Mountains. Apparently, this zone is a major crustal feature upon which the negative gravity anomaly coincident with the high heat flow is superimposed. The correlation, or lack thereof, of the heat flow, depth to Curie point, gravity field, crustal electrical resistivity, crustal seismic velocity, and geology in the High/Western Cascade Ranges is summarized. Many of the data show aspects that can be interpreted in relation to possible high temperatures in the midcrust of the Cascade Range. The High Cascade Range midcrust has unusually high temperatures and contains a zone of magma staging at 10±2 km depth that can also be identified in subdued form in the Cascade Range in Washington and British Columbia.