Trench floor depositional response to glacio-eustatic changes over the last 45 ka, northern Hikurangi subduction margin, New Zealand
Trench floor depositional response to glacio-eustatic changes over the last 45 ka, northern Hikurangi subduction margin, New Zealand
复制标题
DOI：
10.1080/00288306.2022.2099432
复制
发表时间：
2022-07
影响因子：
2.2
通讯作者：
A. Woodhouse;P. Barnes;Anthony Shorrock;L. Strachan;M. Crundwell;H. Bostock;J. Hopkins;S. Kutterolf
中科院分区：
文献类型：
--
作者：
A. Woodhouse;P. Barnes;Anthony Shorrock;L. Strachan;M. Crundwell;H. Bostock;J. Hopkins;S. Kutterolf
冰川-海平面循环导致所有类型的大陆边缘的沉积作用发生变化。然而，在活动俯冲带，缺乏关于海平面升降旋回的沉积速率数据。在国际大洋发现计划第375次考察期间，对北部Hikurangi海槽遗址U1520的上部∼110 m进行取心，发现了一个以浊积为主的层序，沉积于∼最后45年(海洋同位素阶段1-3)。我们提出了一个综合了放射性碳测年、沉积年代学和δ18O地层学的年龄模型，以评估地层重现期和沉积堆积率。我们的分析表明，平均床阻力指数在MIS1的∼322年、MIS2的∼49年和MIS3的∼231年之间变化。在最后一次冰盛期和第三次大冰期期间，雷达吸收率的变化很大(6倍)且变化剧烈，最高可达∼10 m/ /Kyr，而在第三次冰期和第三次冰期期间，最高可达1 kgm/kyr。
Glacio-eustatic cycles lead to changes in sedimentation on all types of continental margins. There is, however, a paucity of sedimentation rate data over eustatic sea-level cycles in active subduction zones. During International Ocean Discovery Program Expedition 375, coring of the upper ∼110 m of the northern Hikurangi Trough Site U1520 recovered a turbidite-dominated succession deposited during the last ∼45 kyrs (Marine Isotope Stages (MIS) 1–3). We present an age model integrating radiocarbon dates, tephrochronology, and δ18O stratigraphy, to evaluate the bed recurrence interval (RI) and sediment accumulation rate (SAR). Our analyses indicate mean bed RI varies from ∼322 yrs in MIS1, ∼49 yrs in MIS2, and ∼231 yrs in MIS3. Large (6-fold) and abrupt variations in SAR are recorded across MIS transitions, with rates of up to ∼10 m/kyr occurring during the Last Glacial Maximum (LGM), and <1 m/kyr during MIS1 and 3. The pronounced variability in SAR, with extremely high rates during the LGM, even for a subduction zone, are the result of changes in regional sediment supply associated with climate-driven changes in terrestrial catchment erosion, and critical thresholds of eustatic sea-level change altering the degree of sediment bypassing the continental shelf and slope via submarine canyon systems.