Transient convective uplift of an ancient buried landscape
Transient convective uplift of an ancient buried landscape
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DOI：
10.1038/ngeo1191
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发表时间：
2011-08-01
影响因子：
18.3
通讯作者：
Richardson, Chris
中科院分区：
文献类型：
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作者：
Hartley, Ross A.;Roberts, Gareth G.;Richardson, Chris
北大西洋的沉积盆地保留了新生代间歇性隆起的记录（1）。这些海拔变化被认为是由底层冰岛地幔柱内的温度变化引起的（2）。当欧洲大陆架的一部分被抬升到海平面以上时，新的景观因侵蚀而被雕刻出来，但这些景观随后下沉并被埋在海洋沉积物之下。在这里，我们使用三维地震数据来重建这些古老的景观，形成了欧洲西北海岸在古新世始新世热最大。我们确定了一个排水网络内的景观，并通过模拟该网络内的个人河流的配置文件，我们重建的历史表面隆起。我们表明，景观被提升到海平面以上，在一系列的三个离散的步骤，每个200- 400米。经过大约100万年的空中暴露，这一景观被重新掩埋。我们使用的幅度和持续时间的隆起，以限制温度和速度的地幔柱异常，驱动景观的形成。我们的结论是，热的，化学贫化，地幔物质的脉冲在岩石圈板块之下以类似于35厘米/年（-1）的速度径向扩散。
Sedimentary basins in the North Atlantic Ocean preserve a record of intermittent uplift during Cenozoic times(1). These variations in elevation are thought to result from temperature changes within the underlying Icelandic mantle plume(2). When parts of the European continental shelf were episodically lifted above sea level, new landscapes were carved by erosion, but these landscapes then subsided and were buried beneath marine sediments(3). Here, we use three-dimensional seismic data to reconstruct one of these ancient landscapes that formed off the northwest coast of Europe during the Palaeocene-Eocene Thermal Maximum. We identify a drainage network within the landscape and, by modelling the profiles of individual rivers within this network, we reconstruct the history of surface uplift. We show that the landscape was lifted above sea level in a series of three discrete steps of 200-400m each. After about 1 million years of subaerial exposure, this landscape was reburied. We use the magnitude and duration of uplift to constrain the temperature and velocity of a mantle-plume anomaly that drove landscape formation. We conclude that pulses of hot, chemically depleted, mantle material spread out radially beneath the lithospheric plate at velocities of similar to 35 cm yr(-1).