High-resolution record reveals climate-driven environmental and sedimentary changes in an active rift.
High-resolution record reveals climate-driven environmental and sedimentary changes in an active rift.
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高分辨率记录揭示了活跃裂谷中气候驱动的环境和沉积变化。
DOI：
10.1038/s41598-019-40022-w
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发表时间：
2019
影响因子：
4.6
通讯作者：
McNeill LC
中科院分区：
文献类型：
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作者：
McNeill LC
年轻的裂谷是由构造和表面过程以及气候共同形成的，但很少有记录来评估这些过程在早期裂谷盆地发育的较长时期内的相互作用。在这里，我们展示了当一个年轻的裂谷连接到全球海洋时，沉积物通量和古环境变化的最长和最高分辨率记录。国际海洋发现计划(IODP)在科林斯裂谷381号考察的新结果显示，随着海平面相对于这个半孤立盆地边界的海床起伏，盆地古环境的KYR旋回变化达到了10s-100s，并揭示了输送到裂谷中的沉积物的体积和性质发生了实质性的相应变化。间冰期，当盆地为海相时，沉积速率较低(全新世除外)，生物扰动和有机碳浓度较高。在冰期，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，冰川时期植被覆盖率的减少推动了裂谷侧翼更高的沉积物通量。这些盆地充填速率和类型的轨道-时间尺度变化可能会影响早期的裂谷沉积和断裂过程，可能包括全球大陆深部边缘的同裂谷地层学、沉积物埋藏速率和有机碳通量与保存。
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.