Measuring the pulse of a plume with the sedimentary record
Measuring the pulse of a plume with the sedimentary record
复制标题
用沉积记录测量羽流的脉冲
作者：
N. White;B. Lovell
与地幔柱活动相关的岩浆底侵是驱动区域地表隆起和大部分大陆剥蚀的重要机制。这种隆起发生得很快，因为大量玄武岩熔体在地质上短时间内（1-10 Myr）被添加到地壳中，并可能导致大量碎屑沉积物流入周围盆地。这一过程的一个深入研究的例子发生在古近纪时期的北海盆地，由于相对海平面的间歇性变化，当沙子通过浊流和泥石流从陆架向下倾斜时，触发了离散的沉积脉冲。在这里，我们将这些沉积物脉冲的时间与推断由欧洲西北部大陆架上的间歇性岩浆底侵引起的表面隆起的时间相关联。这种岩浆活动与冰岛地幔柱的活动有关，表明单个沉积脉冲提供了地幔柱活动的潜在敏感测量，因此可用于解决地幔对流理论研究预测的地幔柱活动随时间变化的波动。
Magmatic underplating associated with mantle plume activity is an important mechanism for driving regional surface uplift and denudation of large portions of the continents,. Such uplift occurs rapidly because substantial volumes of basaltic melt are added to the crust over geologically short periods of time (1–10 Myr), and can lead to large amounts of clastic sediment being shed into surrounding basins. An intensively studied example of this process occurred in the North Sea basin during the Palaeogene period, where discrete pulses of deposition were triggered when sands were remobilized downslope from the shelf by turbidity currents and debris flows as a result of episodic changes of relative sea level. Here we correlate the timing of these sediment pulses with the timing of surface uplift inferred to have been caused by episodic magmatic underplating on the continental shelf of northwestern Europe. This magmatism was related to activity of the Iceland plume, suggesting that individual pulses of sedimentation provide a potentially sensitive measure of plume activity, and so may be used to resolve time-dependent fluctuations in mantle plume activity predicted by theoretical studies of mantle convection.