...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Earth and Planetary Science Letters: A Letter Journal Devoted to the Development in Time of the Earth and Planetary System >Determining the growth rate of topographic relief using in situ-produced Be-10: A case study in the Black Forest, Germany
【24h】

Determining the growth rate of topographic relief using in situ-produced Be-10: A case study in the Black Forest, Germany

机译：使用原位生成的Be-10确定地形起伏的增长率：以德国黑森林为例

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

To determine how topographic relief in mountainous regions evolves through time we present a new approach that uses in situ-produced cosmogenic Be-10 to quantify (1) spatially averaged denudation rates of small watersheds and (2) local denudation rates of the ridge crests bounding these basins. The technique is applied to two catchments in the Black Forest, a forested mountain range with a local relief of a few hundred meters, which is typical for ranges in central Europe. Both the Acher and the Gutach catchments expose predominantly Carboniferous granite, and only minor amounts of high-grade gneiss and Triassic sandstone. The latter occurs on ridges defining the eastern boundaries of the catchments, above a regional unconformity. In the Acher and northern Gutach watersheds denudation rates of subcatchments derived from Be-10 concentrations in stream sediment range from 52 to 87 mm/ka and 59 to 91 mm/ka, respectively. In contrast, grus samples from the ridge crests bounding both watersheds yield lower denudation rates of 34 to 59 mm/ka. The differences in denudation rates for sample pairs from individual subcatchments and adjacent ridge crests reveals that topographic relief is growing at a mean rate of 24 12 mm/ka (with the exception of the flat southwestern part of the Gutach catchment, where catchment-wide denudation rates are similar to the rate of ridge crest lowering). The inferred rates of denudation and relief growth are consistent with erosion rates calculated from the known thickness of Triassic to Lower Jurassic sediments, which were once present above the regional unconformity but have been largely eroded during the exhumation of the Black Forest. The onset of exhumation similar to 19 Ma ago is constrained by thermal modelling of apatite fission track data, which suggest a cooling rate of similar to 3 degrees C/Ma. Combined with a geothermal gradient of 30 to 40 degrees C/km this cooling rate yields an average exhumation rate of 75-100 mm/ka for the modelled apatite fission track data, which is comparable to spatially averaged denudation rates derived from cosmogenic Be-10. Our new approach may help to determine whether tectonically active mountain ranges are in a topographic steady state, in which rates of rock uplift and denudation are equal, or if such a dynamic equilibrium has not yet been attained.
机译：为了确定山区的地形起伏如何随时间演变，我们提出了一种新方法，该方法使用原位产生的宇宙成因Be-10来量化（1）小流域的空间平均剥蚀率和（2）脊顶边界的局部剥蚀率这些盆地。该技术被应用于黑森林的两个集水区，黑森林是一个有几百米局部浮雕的森林山脉，这在中欧地区是典型的。阿彻河和古塔赫河集水区都主要露露石炭纪花岗岩，只有少量高品位片麻岩和三叠纪砂岩。后者发生在界定流域东部边界的山脊上，区域不整合上方。在阿彻河和古塔赫河北部流域，河流沉积物中源自Be-10浓度的子汇水面积的剥蚀率分别为52至87 mm / ka和59至91 mm / ka。相比之下，来自两个流域边界的山脊顶的粗粒样品的剥蚀率较低，为34至59 mm / ka。来自单个子汇水区和相邻脊顶的样本对的剥蚀率差异表明，地形起伏以24 12 mm / ka的平均速率增长（Gutach流域西南平坦的部分除外，那里集水区范围的剥蚀比率类似于脊峰下降的比率）。推测的剥蚀速率和浮雕生长速率与从三叠纪至下侏罗统沉积物的已知厚度计算的侵蚀速率相一致，这些沉积速率曾经存在于区域不整合面之上，但在黑森林掘出期间已受到很大侵蚀。磷灰石裂变径迹数据的热模型限制了与19 Ma以前相似的发掘开始，这表明冷却速率接近3 C / Ma。结合30至40摄氏度/公里的地热梯度，此冷却速率对模拟的磷灰石裂变径迹数据得出的平均发掘速率为75至100毫米/千卡，这与源自宇宙成因的Be-10的空间平均剥蚀速率相当。我们的新方法可能有助于确定构造活跃的山脉是否处于地形稳定状态，在该状态下岩石的隆起和剥蚀速率相等，或者是否尚未达到这种动态平衡。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

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