Age, spreading rates, and spreading asymmetry of the world's ocean crust
Age, spreading rates, and spreading asymmetry of the world's ocean crust
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DOI：
10.1029/2007gc001743
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发表时间：
2008-04-03
影响因子：
3.5
通讯作者：
Roest, Walter R.
中科院分区：
文献类型：
--
作者：
Mueller, R. Dietmar;Sdrolias, Maria;Roest, Walter R.
我们提出了四个同伴的数字模型的年龄，年龄的不确定性，扩散率和扩散不对称性的世界海洋盆地的地理和墨卡托网格2弧分分辨率。网格包括所有主要海洋盆地的数据以及弧后盆地的详细重建。在每个网格节点的年龄，扩展速率和不对称性是通过扩展方向上相邻海底等时线之间的线性插值来确定的。已查明的最古老的磁异常与大陆地壳之间的洋底年龄是通过对被动大陆边段年龄的地质估计来推算的。与海洋磁异常识别相一致的网格单元的年龄不确定性，观测或旋转到其共轭脊侧翼，是基于网格年龄和观测年龄之间的差异。不确定性也是给定网格单元到最近年龄观测值的距离以及与断裂带或其他年龄不连续性的接近程度的函数。地壳增生的不对称性似乎经常与软流圈从地幔柱流到扩张脊，导致脊向热点跳跃有关。我们还使用新的年龄网格计算全球剩余基底深度网格之间的差异观测到的海洋基底深度和预测深度使用三种替代的年龄-深度关系。新的一组网格有助于调查突出的负深度异常，这可能是交替有关俯冲板片材料下降的地幔或软流圈流。我们的数字网格和相关的相对和绝对板块运动模型与地震层析成像和地幔对流模型的输出相结合，是一套有价值的工具来调查地球动力学问题。
We present four companion digital models of the age, age uncertainty, spreading rates, and spreading asymmetries of the world's ocean basins as geographic and Mercator grids with 2 arc min resolution. The grids include data from all the major ocean basins as well as detailed reconstructions of back-arc basins. The age, spreading rate, and asymmetry at each grid node are determined by linear interpolation between adjacent seafloor isochrons in the direction of spreading. Ages for ocean floor between the oldest identified magnetic anomalies and continental crust are interpolated by geological estimates of the ages of passive continental margin segments. The age uncertainties for grid cells coinciding with marine magnetic anomaly identifications, observed or rotated to their conjugate ridge flanks, are based on the difference between gridded age and observed age. The uncertainties are also a function of the distance of a given grid cell to the nearest age observation and the proximity to fracture zones or other age discontinuities. Asymmetries in crustal accretion appear to be frequently related to asthenospheric flow from mantle plumes to spreading ridges, resulting in ridge jumps toward hot spots. We also use the new age grid to compute global residual basement depth grids from the difference between observed oceanic basement depth and predicted depth using three alternative age-depth relationships. The new set of grids helps to investigate prominent negative depth anomalies, which may be alternatively related to subducted slab material descending in the mantle or to asthenospheric flow. A combination of our digital grids and the associated relative and absolute plate motion model with seismic tomography and mantle convection model outputs represents a valuable set of tools to investigate geodynamic problems.