Heat flow and elevation of the marginal basins of the western Pacific
Heat flow and elevation of the marginal basins of the western Pacific
复制标题
西太平洋边缘盆地的热流和海拔
DOI：
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发表时间：
1972
期刊：
影响因子：
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通讯作者：
J. Sclater
中科院分区：
文献类型：
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作者：
J. Sclater
在西太平洋海沟-岛弧系统向陆的许多边缘盆地中观测到高热流和浅地壳深度。西北太平洋的所有盆地都有足够的热流数据，除了菲律宾盆地的西部深处，都显示出较高的平均热流。这与西南太平洋形成鲜明对比，那里只有斐济高原和劳盆地有高热流。所有活跃的大洋中脊都显示出热流与海拔之间的一致关系：年轻的海脊高而浅，而洋壳老的海脊则一致而深。在缺乏边缘盆地的磁力数据的情况下，这种关系被用来确定这些盆地是否具有与南极海脊相同的热力和动力结构。来自西南太平洋盆地的热流和高程数据与脊数据是兼容的，而来自日本深海平原、Parece Vela盆地和西北太平洋四国盆地的热流和高程数据对于它们的平均深度而言具有太高的热流。有令人信服的证据表明，西北太平洋边缘盆地的起源和发展归功于岛弧系统的大规模地壳向陆伸展。然而，与这种扩张相关的洋壳侵入不能单独充分解释热流和高程数据。除侵入过程外，还讨论了影响热流和地壳深度分布的其它三个因素：（1）持续的初始侵入，它提高了地壳的“有效”热导率，从而提高了这些盆地的热流：（2）西北太平洋岛弧系统向陆方向较薄的岩石圈板块的发展;（3）作用于上地幔的向陆的下行板块的动力，降低了边缘盆地的观测高程。这三个因素都存在问题，但只使用第二个因素的模型是首选，因为它很容易开发，并且与刚性板块构造兼容。
High heat flow and shallow crustal depths have been observed in many marginal basins landward of the trench-island arc system in the western Pacific. All the basins in the north-western Pacific where adequate heat-flow data exist, except the deep west Philippine basin, show a high mean heat flow. This is in marked contrast to the southwestern Pacific, where only the Fiji plateau and Lau basin have high heat flow. All active midocean ridges show a uniform relationship between heat flow and elevation: high and shallow where the ridge is young, and uniform and deep where the oceanic crust is old. In the absence of magnetic data in the marginal basins, this relationship has been used to determine whether or not these basins have the same thermal and dynamic structure as the midocean ridges. The heat flow and elevation data from the southwestern Pacific basins are compatible with the ridge data, whereas heat flow and elevation data from the Japan abyssal plain, Parece Vela basin, and the Shikoku basin in the northwestern Pacific have too high a heat flow for their mean depth. Convincing evidence has been presented that the marginal basins of the northwestern Pacific owe their origin and development to large-scale crustal extension landward of the island arc system. However, the intrusion of oceanic crust associated with this extension cannot alone adequately account for the heat flow and elevation data. Three other factors are discussed that, in addition to the intrusion process, may account for the observed distribution of heat flow and crustal depth: (1) continuous incipient intrusion, which raises the ‘effective’ thermal conductivity of the crust and hence the heat flow in these basins; (2) development of a thinner lithospheric plate landward of the island arc system of the northwestern Pacific; and (3) dynamic forces acting on the upper mantle landward of the downgoing slab, decreasing the observed elevation of the marginal basins. There are problems with all three of these factors, but a model using only the second is preferred, because it is simple to develop and is compatible with rigid plate tectonics.