Deciphering the Record of Sediment Transfer and Deposition Across Continental Slopes and the Margins of Other Deep-Water Basins

破译大陆斜坡和其他深水盆地边缘的沉积物转移和沉积记录

• 批准号: 341715-2013
• 负责人: Hubbard, Stephen
• 金额: $ 2.91万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=633807
• 关键词: Deciphering; Record; Sediment; Transfer; Deposition

The floors of the world's deepest oceans arguably represent the most poorly understood land-/sea-scape on the planet, owing primarily to their inaccessibility and associated extreme conditions (e.g., high pressure). As we seek information about other planets in our solar system such as Mars, our oceans remain a significantly understudied frontier on planet Earth. Large subaqueous avalanches, or gravity flows, are known to transport fluid and sediment through river-like channels across vast expanses of the seafloor on continental margins, in water depths of 1-3 km or more. Unfortunately, direct measurement of these events is often very difficult, and we are forced to draw insight about them from indirect means, including destruction of infrastructure on the seafloor such as communication cables and pipelines. Another means to better understand these high-energy events in the deep-sea is to study their deposits, which can be captured in drillcores, or in the case of ancient examples, uplifted into mountain belts by major tectonic events. The proposed research will focus on Cretaceous-aged deep-sea deposits that are exposed at the Earth's surface in outcrops of southern Chile and western British Columbia. Evidence for immense gravity flows that shaped the ancient seascapes are present, represented by deep erosion surfaces associated with scours and channels, distinctive units that were left behind as gravity flows passed over an area, and thick deposits that accumulated when gravity flows lost their energy and came to rest. The research entails mapping geological features and rock types exposed in outcrops in each field area, and then incorporating the information into three-dimensional computer models, which reveal the geometry of geomorphological features (e.g., channels) and the character of their component rock types. By studying these ancient deposits in Chile and British Columbia, we will gain insight into sediment transfer in arguably the last true Earthly frontier: our deep oceans. An important applied motivation for this study is to better constrain potential hydrocarbon-bearing deep-water rocks on the margins of Canada and other continental slopes around the globe.

可以说，世界上最深的海洋的海底代表了地球上最不为人所知的陆地/海洋景观，主要是由于它们难以接近和相关的极端条件（例如高压）。当我们寻找太阳系中其他行星的信息时，比如火星，我们的海洋仍然是地球上一个未被充分研究的前沿。大型水下雪崩，或重力流，已知通过河流般的通道在大陆边缘的广阔海底，在水深1-3公里或更深的地方运输流体和沉积物。不幸的是，对这些事件的直接测量通常是非常困难的，我们被迫通过间接手段来了解它们，包括对海底基础设施（如通信电缆和管道）的破坏。另一种更好地了解深海中这些高能事件的方法是研究它们的沉积物，这些沉积物可以通过钻芯捕获，或者在古代的例子中，通过主要的构造事件上升到山带。拟议中的研究将集中在智利南部和不列颠哥伦比亚省西部地表露出的白垩纪深海沉积物上。有证据表明，巨大的重力流塑造了古代的海洋景观，这些证据表明，与冲刷和河道相关的深度侵蚀表面，重力流经过一个地区时留下的独特单元，以及重力流失去能量并停止时积累的厚沉积物。这项研究需要绘制地质特征和在每个野外露头暴露的岩石类型，然后将这些信息纳入三维计算机模型，从而揭示地貌特征的几何形状（例如，水道）及其组成岩石类型的特征。通过研究智利和不列颠哥伦比亚省的这些古老沉积物，我们将深入了解地球上最后一个真正的边界：我们的深海。这项研究的一个重要应用动机是更好地约束加拿大和全球其他大陆斜坡边缘潜在的含油气深水岩石。