Hot regions and the origin of marginal basins in the western Pacific
Hot regions and the origin of marginal basins in the western Pacific
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DOI：
10.1016/0040-1951(86)90145-9
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发表时间：
1986-02
期刊：
影响因子：
2.9
通讯作者：
A. Miyashiro
中科院分区：
文献类型：
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作者：
A. Miyashiro
火山区与板块边界没有成因关系，可以分为两类：一是直径几百公里、相对于地幔深部位置几乎固定的热点，二是直径几千公里、迁移比较自由的热区。据观察，西太平洋边缘盆地的年龄大于15Ma，向北逐渐变年轻（南斐济盆地除外）。这导致了边缘盆地的扩张是由地幔上涌引起的，与一个迁移的热区有关，并且一个热区从晚白垩世的澳大利亚地区开始，通过古新世、始新世、渐新世和早中新世先后向北迁移，形成了塔斯曼、珊瑚海、加罗林、华南、帕雷斯贝拉、四国和日本盆地。这个炎热的地区目前位于中国北方、蒙古和邻近地区的下面。另一个热区被认为是造成南斐济海盆和所有目前正在扩张的西南太平洋海盆扩张的原因。个别边缘盆地的扩张发生在热区域经过相关区域的短期内。这一假说的主要优点是可以解释西太平洋边缘盆地的位置与时代的关系以及扩张时间短的原因。（虽然不总是）在俯冲带附近的覆盖板块中，因为在这样的背景下，扩张的边缘盆地很容易被附近俯冲带的向海洋运动或大陆运动所容纳。运动和俯冲的海洋板块。有一些边缘盆地是在其他构造环境中形成的，并受到其他补偿俯冲机制的容纳。据推测，超大陆盘古大陆的分裂也主要是由地幔上涌的影响造成的，地幔上涌与后来向北迁移的同一热区有关，在西太平洋形成边缘盆地。这一假设的主要依据是，盘古大陆的分裂是在中白垩世在澳大利亚地区完成的，而西太平洋边缘盆地的扩张则是在晚白垩世在澳大利亚地区开始的。
Volcanic provinces, showing no genetic relationship to plate boundaries, may be classified into two categories: hot spots which are a few hundred kilometers across and may be nearly fixed in position with respect to deep mantle, and hot regions which are a few thousand kilometers across and can migrate more freely. The mantle upwellings which presumably give rise to them may originate at different depths by different causes.It is observed that the marginal basins, older than 15 Ma, of the western Pacific become progressively younger northward (with the exception of the South Fiji Basin). This leads to the hypothesis that the spreading of marginal basins was caused by the mantle upwelling associated with a migrating hot region, and that a hot region which started from the Australia region in the Late Cretaceous, migrated northward successively creating the Tasman, Coral Sea, Caroline, South China, Parece Vela, Shikoku, and Japan Basins through Paleocene, Eocene, Oligocene, and Early Miocene time. This hot region presently underlies northern China, Mongolia and adjacent areas. Another hot region is assumed to have caused the spreading of the South Fiji Basin and all the currently spreading basins in the southwestern Pacific. Spreading of individual marginal basins occurred during the short period when a hot region was passing the pertinent area. The main merit of this hypothesis is that it can explain the relationship between the location and age as well as the short duration of spreading, of western Pacific marginal basins.Marginal basins are formed commonly (though not always) in the overriding plates near subduction zones, because in such a setting a spreading marginal basin is readily accommodated either by an oceanward movement of the nearby subduction zone or by a continentward movement and subduction of the overriding oceanic plate. There are a few marginal basins that were formed in other tectonic settings and accommodated by some other mechanism of compensative subduction.Presumably the splitting of the supercontinent Pangea was also caused mainly by the effect of the mantle upwelling associated with the same hot region that later migrated northward, creating marginal basins in the western Pacific. The main basis for this presumption is the fact that the splitting of Pangea was completed in the Australia region in Middle Cretaceous time, whereas the spreading of marginal basins in the western Pacific began in the same Australia region in the Late Cretaceous immediately following.