Fluvio-deltaic avulsions during relative sea-level fall
Fluvio-deltaic avulsions during relative sea-level fall
复制标题
海平面相对下降期间的河流三角洲撕脱
作者：
Nijhuis A
了解河流对相对海平面(RSL)变化的响应对于预测河流沉积地层学和源汇动力学至关重要。最近的理论工作表明，河流在RSL下降过程中可能会继续恶化，但需要现场数据来验证这种反应并研究泥沙沉积过程。我们通过野外工作和模拟表明，河流三角洲体系在RSL坠落期间可以保持沉积或保持原状，导致三角洲叶撕裂的超高和延续。现场是加拿大纽芬兰-拉布拉多的鹅河，在过去的5年里，它经历了大约3-4 mm yr-1的RSL稳定下降。来自冰川后的均衡反弹。海拔分析和光激发发光测年表明，鹅河在RSL瀑布期间撕裂并沉积了三个三角洲叶。Delft3D软件的模拟结果表明，如果特征河流响应时间长于RSL下落的持续时间，则河流系统仍处于加积或分级状态，并在RSL下落过程中由于超高而继续撕裂。有趣的是，我们发现，如果系统响应时间保持比RSL下降的持续时间更长的话，RSL下降的速度越快，窃取就会变得更加频繁。这项工作表明，RSL下降速率可能通过控制沉积三角洲叶的数量来影响下降阶段或强迫海退沉积的结构。
Understanding river response to changes in relative sea level (RSL) is essential for predicting fluvial stratigraphy and source-to-sink dynamics. Recent theoretical work has suggested that rivers can remain aggradational during RSL fall, but field data are needed to verify this response and investigate sediment deposition processes. We show with field work and modeling that fluvio-deltaic systems can remain aggradational or at grade during RSL fall, leading to superelevation and continuation of delta lobe avulsions. The field site is the Goose River, Newfoundland-Labrador, Canada, which has experienced steady RSL fall of around 3–4 mm yr–1in the past 5 k.y. from post-glacial isostatic rebound. Elevation analysis and optically stimulated luminescence dating suggest that the Goose River avulsed and deposited three delta lobes during RSL fall. Simulation results from Delft3D software show that if the characteristic fluvial response time is longer than the duration of RSL fall, then fluvial systems remain aggradational or at grade, and continue to avulse during RSL fall due to superelevation. Intriguingly, we find that avulsions become more frequent at faster rates of RSL fall, provided the system response time remains longer than the duration of RSL fall. This work suggests that RSL fall rate may influence the architecture of falling-stage or forced regression deposits by controlling the number of deposited delta lobes.
登录
查看更多内容
沿海平原河流对沉积期相对海平面下降同种异体控制的响应
DOI：
--
发表时间：
2007
期刊：
Sedimentology 53
影响因子：
--
作者：
John B.Swenson
通讯作者：
John B.Swenson
关于拉布拉多梅尔维尔湖区梯田年代测定的说明。
影响因子：
56.9
作者：
W. Blake
通讯作者：
W. Blake
河流撕脱方式是否受漫滩形态动力学控制
DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
E. Hajek;D. Edmonds
通讯作者：
D. Edmonds
矿物质营养和烟草花叶病毒引起的局部病变的大小。
影响因子：
56.9
作者：
M. Chessin;H. Scott
通讯作者：
H. Scott
影响因子：
5.8
作者：
T. Muto;R. Steel
通讯作者：
R. Steel