...
  • 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 >The diachroneity of alluvial-fan lithostratigraphy? A test case from southeastern Ebro basin magnetostratigraphy
【24h】

The diachroneity of alluvial-fan lithostratigraphy? A test case from southeastern Ebro basin magnetostratigraphy

机译：冲积扇岩性地层学的两面性？东南埃布罗盆地地磁地层的一个测试案例

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

Alluvial-fan strata contain valuable proxy data for kinematic, climatic and sediment-flux phenomena associated with high-relief source regions. Proper application of this data is dependent upon acquisition of accurate high-resolution chronostratigraphic data, best achieved through magnetostratigraphy. Collection of magnetostratigraphic and other proxy data from composite alluvial-fan sections assumes the chronostratigraphic significance of lithostratigraphy. We present the first test of this assumption with new magnetostratigraphy collected from Palcogene rocks of the southeastern Ebro basin. We report five new magnetostratigraphic sections that collectively sample 850 m of alluvial-fan and associated fluvial strata. One-hundred meters of lithostratigraphic overlap between these sections reveals equivalent magnetic polarities over short along-strike distances (similar to 200-2000 m). However, lithostratigraphic correlation of these sections with the magneto stratigraphy of continuously exposed strata eight kin away reveals discrepancies in magnetic polarity trends and age interpretations. Correlation of our 760 m composite magnetostratigraphic section with the Paleogene geomagnetic polarity time scale suggests that this section spans from ca. 31.3 to 27.7 Ma (C12r-C9n; early to late Oligocene). This correlation. implies steady sedimentation rates of similar to 12 cm/ka for fluvial facies and similar to 32 crn/ka for alluvial-fan facies. Alternative interpretations that force chronostratigraphic correlation with the lithostratigraphically equivalent interval generate unsteady and/or unlikely sedimentation rates in one or both of the stratigraphies and require rejection of multiple well-constrained polarity zones. The absence of significant surfaces of erosion or paleosol development argue against these alternative interpretations and suggest that even in the best exposed study areas, alluvial-fan successions may be diachronous and preclude lateral extrapolation of chronostratigraphic and other proxy data. Interpretations and models based upon data collected from alluvial-fan strata may be tenuous unless supported by sufficient spatial overlap to constrain the relationship between time surfaces and rock surfaces. (C) 2007 Elsevier B.V. All rights reserved.
机译：冲积扇地层包含与高起伏源区有关的运动学，气候学和沉积物通量现象的有价值的替代数据。此数据的正确应用取决于准确的高分辨率年代地层数据的获取，最好通过地磁地层来实现。从复合冲积扇剖面收集磁地层和其他替代资料，假定岩石地层学具有年代地层意义。我们用从东南埃布罗盆地的帕尔金吉岩中收集的新地层学提出了这个假设的第一个检验。我们报告了五个新的磁地层剖面，这些剖面共同采样了850 m的冲积扇和相关的河流地层。这些部分之间一百米的岩石地层学重叠表明，在短的沿走向距离（类似于200-2000 m）上，磁极等效。然而，这些断层的地层岩石地层学特征与连续暴露在外的8层磁层的地磁学关系揭示了磁极趋势和年龄解释上的差异。我们的760 m复合磁地层剖面与古近纪地磁极性时标的相关性表明，该剖面的范围大约为。 31.3至27.7 Ma（C12r-C9n;早至晚渐新世）。这种相关性。意味着河流相的稳定沉降速率接近12 cm / ka，冲积扇相的沉积速率接近32 crn / ka。迫使年代地层与岩层地层等效间隔相关的其他解释会在一个或两个地层中产生不稳定和/或不太可能的沉积速率，并需要排除多个受严格约束的极性带。没有明显的侵蚀或古土壤发育表面，则与这些替代解释相抵触，这表明即使在最佳裸露的研究区域，冲积扇演替也可能是历时性的，并排除了年代地层和其他类似资料的横向外推。除非有足够的空间重叠来支持时间面和岩石面之间的关系，否则基于从冲积扇地层收集的数据的解释和模型可能是微不足道的。 （C）2007 Elsevier B.V.保留所有权利。

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