• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文OA文献 >Accommodation Space Controls on the Latest Pleistocene and Holocene (16–0 ka) Sediment Size and Bypassing in the Lower Columbia River Valley: A Large Fluvial–Tidal System in Oregon and Washington, USA
【2h】

Accommodation Space Controls on the Latest Pleistocene and Holocene (16–0 ka) Sediment Size and Bypassing in the Lower Columbia River Valley: A Large Fluvial–Tidal System in Oregon and Washington, USA

机译：最新更新世和全新世（16-0 ka）沉积物尺寸和绕过哥伦比亚河谷下游的住宿空间控制：美国俄勒冈州和华盛顿的大型河流 - 潮汐系统

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务，本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文，但由于OA文献来源多样且变更频繁，仍可能出现获取不到、文献不完整或与标题不符等情况，如果获取不到我们将提供退款服务。请知悉。
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In this study, we establish the roles that increasing basin accommodation space have on sediment size and bypassing in the transgressive fill (16–0 ka) in the submerged Lower Columbia River Valley (LCRV). The antecedent forearc valley (225 km in length, 4–8 km in width, and 60–115 m in axial valley depth) is characterized by high sediment supply rates (10–15 million t y-1) but no delta at its mouth to the Pacific Ocean. Core sample sediment textures (N ¼ 1600) are analyzed from 3000 m of borehole sections in 58 representative boreholes to characterize the ancestral valley fill: 57% sand, 17% muddy sand, 12% sandy mud, and 14% mud (total fill volume¼77 km3). Decreasing mud endmember texture from between 30 and 60% (early Holocene) to 18% (late Holocene) is directly related to (1) declining rates of increasing basin accommodation space and (2) increasing sediment bypassing through the LCRV. Both conditions result from decreasing rates of sea level rise (15.0–1.5 mm y-1) in Holocene time. The overall coarsening of sediments, both upvalley and upsection, is controlled by declining rates of increasing basin accommodation space (5.66 million–0.57 million m3 y-1) during middle to late Holocene time. Differences between middle and late Holocene sediment accumulation rates yield bedload bypassing rates of 5– 6 million m3 y-1, under assumed conditions of constant sediment supply rates in middle to late Holocene time.
机译：在这项研究中，我们确定了增加盆地容纳空间对沉没的下哥伦比亚河谷（LCRV）的海侵填充物（16-0 ka）中的沉积物大小和绕过作用的作用。前前谷（长225 km，宽4–8 km，轴向谷深60–115 m）的特点是沉积物供应率高（10–15百万吨y-1），但其口无三角洲到太平洋。从58个代表性钻孔的3000 m钻孔截面中分析岩心样品的沉积物质地（N¼1600），以表征祖谷填充物：57％的沙子，17％的泥沙，12％的沙泥和14％的泥沙（总填充量¼77 km3）。泥浆端构件的质地从30％到60％（早全新世）减少到18％（晚全新世）直接与（1）盆地容纳空间增加的速率下降和（2）通过LCRV绕开沉积物的增加有关。两种情况都是由于全新世时期海平面上升速率（15.0–1.5 mm y-1）的下降所致。全新世中期至晚期，盆地增加空间和上部沉积物的总体粗化程度受盆地容纳空间增加速率（566万至57万立方米y-1）的降低速率控制。在假设中新世晚期的沉积物供应量恒定的条件下，中新世和晚新世沉积物积累速率之间的差异会导致5-6百万立方米y-1的床荷绕过率。

著录项

  • 作者

    Peterson Curt D.;

  • 作者单位
  • 年度 2013
  • 总页数
  • 原文格式 PDF
  • 正文语种
  • 中图分类

相似文献

  • 外文文献
代理获取

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号