School of Ocean and Earth Science, University of Southampton, Southampton, S014 3ZH, United Kingdom.
Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY, 10964, USA.
Sci Rep. 2019 Feb 28;9(1):3116. doi: 10.1038/s41598-019-40022-w.
Young rifts are shaped by combined tectonic and surface processes and climate, yet few records exist to evaluate the interplay of these processes over an extended period of early rift-basin development. Here, we present the longest and highest resolution record of sediment flux and paleoenvironmental changes when a young rift connects to the global oceans. New results from International Ocean Discovery Program (IODP) Expedition 381 in the Corinth Rift show 10s-100s of kyr cyclic variations in basin paleoenvironment as eustatic sea level fluctuated with respect to sills bounding this semi-isolated basin, and reveal substantial corresponding changes in the volume and character of sediment delivered into the rift. During interglacials, when the basin was marine, sedimentation rates were lower (excepting the Holocene), and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were higher (~2-7 times those in interglacials). We infer that reduced vegetation cover during glacials drove higher sediment flux from the rift flanks. These orbital-timescale changes in rate and type of basin infill will likely influence early rift sedimentary and faulting processes, potentially including syn-rift stratigraphy, sediment burial rates, and organic carbon flux and preservation on deep continental margins worldwide.
年轻的裂谷是由构造和地表过程以及气候共同塑造的，但很少有记录可以评估这些过程在早期裂谷盆地发育的很长一段时间内的相互作用。在这里，我们提供了一段最长、分辨率最高的记录，记录了当一个年轻的裂谷与全球海洋连接时的沉积物通量和古环境变化。国际大洋发现计划（IODP）第 381 次考察在科林斯裂谷的新结果表明，在与限制这个半隔离盆地的海脊相关的海平面相对于海平面波动的情况下，盆地古环境存在 10 到 100 千周的循环变化，并且反映出进入裂谷的沉积物的体积和性质发生了大量相应的变化。在间冰期，当盆地为海洋时，沉积速率较低（全新世除外），生物搅动和有机碳浓度较高。在冰川期，盆地与海洋隔绝，沉积速率较高（约为间冰期的 2-7 倍）。我们推断，冰川期植被覆盖减少导致裂谷侧翼的沉积物通量增加。这些轨道时间尺度上的盆地填充速率和类型的变化可能会影响早期裂谷的沉积和断裂过程，包括同裂谷地层、沉积物埋藏速率以及全球深海大陆边缘的有机碳通量和保存。
