Sediment Characterization at the Equatorial Mid-Atlantic Ridge From P-to-S Teleseismic Phase Conversions Recorded on the PI-LAB Experiment.
Sediment Characterization at the Equatorial Mid-Atlantic Ridge From P-to-S Teleseismic Phase Conversions Recorded on the PI-LAB Experiment.
复制标题
根据 PI-LAB 实验记录的 P 到 S 远震相位转换对赤道大西洋中脊的沉积物进行表征。
DOI：
10.1029/2018gl080565
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发表时间：
2018
影响因子：
5.2
通讯作者：
Agius MR
中科院分区：
文献类型：
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作者：
Agius MR
精确的海洋沉积物特性，例如厚度和地震速度，对于限制沉积速率并对气候变化产生影响，以及对于利用海底地震部署对更深结构进行地震成像，都是重要的。我们分析了岩石圈-软流圈边界被动成像（PI-LAB）实验记录的沉积物-地壳边界的P-到S地震相位转换，以推断大西洋中脊覆盖0到8000万年的海底的沉积物厚度。我们发现Pds ‐ P延迟时间为0.04-0.37 s，或5 - 82-m厚度。沉积物的厚度随年龄而增加。厚度与全球估计的年轻（<1500 - 2000万年）海底一致，但较老的岩石圈较薄。我们的结果可能代表沉积物厚度的下限，因为我们的几个站点位于地形高点。在1.1亿年时，观察到的沉积速率从5毫米/千年下降到1.2毫米/千年，这表明最近生产力的增加与气候变化、风尘通量和/或生物海洋活动有关。
Accurate marine sediment characteristics, for example, thickness and seismic velocity, are important for constraining sedimentation rates with implications for climate variations and for seismic imaging of deeper structures using ocean bottom seismic deployments. We analyzeP‐to‐Sseismic phase conversions from the sediment‐crust boundary recorded by the Passive Imaging of the Lithosphere‐Asthenosphere Boundary (PI‐LAB) experiment to infer the sediment thickness across the Mid‐Atlantic Ridge covering 0‐ to 80‐Myr‐old seafloor. We findPds‐Pdelay times of 0.04–0.37 s, or 5‐ to 82‐m thickness. Sediment thickness increases with age. Thickness agrees with global estimates for young (<15–20 Myr) seafloor but is thinner on older lithosphere. Our result may represent a lower limit on sediment thickness, given that several of our stations are on topographic highs. The sedimentation rate decrease observed from 5 to 1.2 mm/kyr at ∼10 Myr suggests a recent increase in productivity related to climate change, eolian dust fluxes, and/or biogenic marine activity.