{"title":"详细重建云雀盆地","authors":"E. K. Benyshek, B. Taylor, A. M. Goodliffe","doi":"10.1029/2023GC011410","DOIUrl":null,"url":null,"abstract":"<p>An animated 100,000-year-interval tectonic reconstruction of the Woodlark Basin in the southwest Pacific illustrates how, at intermediate initial spreading rates, orogenic continents break up (dyke model), spreading segments nucleate, transform faults initiate and ocean basins evolve. We refine the location/timing of initial seafloor spreading and Euler poles of rotation back to 6.2 Ma. In the easternmost basin, where spreading younger than 2.6 Ma is not co-polar with that to the west, we recognize the formation of a Ghizo microplate and Ranongga Transform Fault at ∼2.6 Ma and a 3-degree rotational opening of the Itina Trough from 2.6 to 1.0 Ma. Allowing for that motion, we show that the 5.2–2.6 Ma seafloor in the easternmost basin formed co-polar with that to the west. 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引用次数: 0
摘要
西南太平洋伍德拉克盆地 10 万年间隔的构造重建动画展示了在中等初始扩张速率下,造山大陆如何断裂(堤坝模型)、扩张段如何成核、转换断层如何启动以及海洋盆地如何演化。我们将初始海底扩张的位置/时间和欧拉旋转极点细化到 6.2 Ma。在最东部的海盆中,小于 2.6 Ma 的扩张与西部的扩张不是同极的,我们认识到在 ∼ 2.6 Ma 形成了 Ghizo 微板块和 Ranongga 转换断层,从 2.6 Ma 到 1.0 Ma 伊蒂纳海槽旋转了 3 度。考虑到这一运动,我们表明最东部海盆的 5.2-2.6 Ma 海底与西部海盆的海底形成了同极性。我们还确定了在 1.0 Ma ∼ 1.0 Ma 海脊跃升重新定向,形成了东北走向的辛博扩张段,其新火山带包括辛博岛及其南面的海底大厦。所提出的海脊传播的确定性模型(由于地形梯度、地幔流离开热点和/或板块运动的变化)与所观察到的不一致;地幔化学异质性和熔融异常是一个有待检验的潜在原因。我们重建了现存最古老大洋地壳的北共轭,并估计其俯冲开始于 ∼ 2.6 Ma,与观测到的板块运动和分段变化同步。在俯冲的地方,共轭断裂边缘之间年轻的大洋岩石圈似乎被重新吸收到地幔中,留下一个板块窗口,太平洋俯冲板块仍然附着在那里。
An animated 100,000-year-interval tectonic reconstruction of the Woodlark Basin in the southwest Pacific illustrates how, at intermediate initial spreading rates, orogenic continents break up (dyke model), spreading segments nucleate, transform faults initiate and ocean basins evolve. We refine the location/timing of initial seafloor spreading and Euler poles of rotation back to 6.2 Ma. In the easternmost basin, where spreading younger than 2.6 Ma is not co-polar with that to the west, we recognize the formation of a Ghizo microplate and Ranongga Transform Fault at ∼2.6 Ma and a 3-degree rotational opening of the Itina Trough from 2.6 to 1.0 Ma. Allowing for that motion, we show that the 5.2–2.6 Ma seafloor in the easternmost basin formed co-polar with that to the west. We also identify a ridge jump reorientation at ∼1.0 Ma that formed the NE-trending Simbo Spreading Segment, whose neovolcanic zone includes Simbo Island and a submarine edifice to its south. Proposed deterministic models of ridge propagation (due to topographic gradients, mantle flow away from hotspots and/or changing plate motion) are not consistent with those observed; mantle chemical heterogeneities and melting anomalies are a potential cause that remains to be tested. We reconstruct the northern conjugate of the oldest extant oceanic crust and estimate the initiation of its subduction at ∼2.6 Ma, concomitant with observed changes in plate motion and segmentation. Where subducted, the young oceanic lithosphere between the conjugate rifted margins appears to be resorbed into the mantle, leaving a slab window where the Pacific subducted slab remains attached.
期刊介绍:
Geochemistry, Geophysics, Geosystems (G3) publishes research papers on Earth and planetary processes with a focus on understanding the Earth as a system. Observational, experimental, and theoretical investigations of the solid Earth, hydrosphere, atmosphere, biosphere, and solar system at all spatial and temporal scales are welcome. Articles should be of broad interest, and interdisciplinary approaches are encouraged.
Areas of interest for this peer-reviewed journal include, but are not limited to:
The physics and chemistry of the Earth, including its structure, composition, physical properties, dynamics, and evolution
Principles and applications of geochemical proxies to studies of Earth history
The physical properties, composition, and temporal evolution of the Earth''s major reservoirs and the coupling between them
The dynamics of geochemical and biogeochemical cycles at all spatial and temporal scales
Physical and cosmochemical constraints on the composition, origin, and evolution of the Earth and other terrestrial planets
The chemistry and physics of solar system materials that are relevant to the formation, evolution, and current state of the Earth and the planets
Advances in modeling, observation, and experimentation that are of widespread interest in the geosciences.