COLLABORATIVE RESEARCH: Experimental Study of Basin Stratigraphy

合作研究：盆地地层学实验研究

• 批准号: 9725989
• 负责人: Christopher Paola
• 金额: $ 16.81万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9725989&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Experimental; Study; Basin

9725989 Paola We propose a three-year program of experimental studies o the formation of physical stratigraphy, using a large new experimental basin with a subsiding floor at the St. Anthony Falls Laboratory (SAFL). This facility allows study of scaled basin processes with complete control of base level, sediment supply and, especially, subsidence pattern and rate. The basin is 13m by 6.5m and allows up to 1.3m of accommodation space for deposition. The subsiding floor comprises 432 independently controllable subsidence cells arranged in a honeycomb pattern. This design allows the creation of a nearly unlimited range of spatial and temporal subsidence patterns. Sediment and water can be fed from anywhere along the basin margin and base level (i.e. water level) is independently controllable. Our first experiments will be aimed at testing some of the first-order predictions of models that have been proposed for formation of physical stratigraphy at basin scales, such as: (1) the relationship of shoreline migration and associated stratigraphy to the interplay between subsidence rate and eustatic sea level; (2) the control of subsidence rate and geometry, and sediment supply, on alluvial coarse-facies distribution (i.e. the origin of syntectonic gravel's); and (3) the influence of subsidence rate and sediment supply on the development of alluvial architecture. Initial results suggest that the experiments can also provide insight on processes such as growth faulting that have not been widely incorporated into existing models. These experiments will use relatively simple subsidence and sediment-feed geometries and will focus on demonstrating "unit" stratigraphic response to changes in one or at most two variables simultaneously. The second set of experiments will focus on 3-D effects in both subsidence and sediment supply, including: 1) 3-D effects of base-level change; 2) propagating active folding in the proximal basin associated with blind thrusts and development of progressive un conformities; 3) sedimentation in an asymmetric half graben combining both transverse and axial drainage. The principal products of the experiments will include: time records of the imposed variables (water and sediment supply, base level, and basement topography); measurements of bed-surface topography through time; video records of flow pattern, shoreline position and other surface features; 3-D block diagrams of the resulting deposits, presented both as directly digitized (photographic) and synthetic seismic images; and synthetic geophysical logs of selected profiles. The synthetic seismics are a crucial link with field observations, since the only way that researchers can obtain views of the rock record comparable to those generated by the experimental basin is through the filter of seismic reflection profiling. The synthetic seismics and well logs, when contrasted against the actual experimental stratigraphy, will also advance our understanding of what is and is not retained from the rock record when it is imaged via these widely used techniques. The experimental results would represent the first test under fully controlled conditions of a wide variety of theoretical predictions of stratigraphic response that have been developed since Pitman's (1978) model of shoreline response to changing sea level. They would also provide a template that could be compared with field observations and interpretations based on seismic and outcrop data. Although laboratory scale models can never capture all of the complex processes that occur in real basins, they serve as a bridge between untested theoretical models and difficult-to-constrain natural examples.

9725989 Paola 我们提出了一项为期三年的物理地层形成实验研究计划，使用圣安东尼瀑布实验室 (SAFL) 的一个带有下沉地板的大型新实验盆地。 该设施可以研究规模盆地过程，完全控制基准面、沉积物供应，特别是沉降模式和速率。 该盆地尺寸为 13m x 6.5m，最多可容纳 1.3m 的沉积空间。 沉降地板由 432 个独立可控的沉降单元组成，这些沉降单元呈蜂窝状排列。 这种设计允许创建几乎无限范围的空间和时间沉降模式。 沉积物和水可以从流域边缘的任何地方供给，并且基准面（即水位）是独立控制的。 我们的第一个实验旨在测试一些为盆地尺度物理地层形成而提出的模型的一阶预测，例如：（1）海岸线迁移和相关地层与沉降率之间相互作用的关系和海平面升降； (2) 沉降速率和几何形状以及沉积物供应对冲积粗相分布（即同构造砾石的起源）的控制； (3)沉降速率和泥沙供给对冲积建筑发育的影响。 初步结果表明，这些实验还可以提供对尚未广泛纳入现有模型的生长断层等过程的见解。 这些实验将使用相对简单的沉降和沉积物供给几何形状，并将重点放在演示“单位”地层对一个或最多两个变量同时变化的响应。 第二组实验将重点关注沉降和沉积物供应的 3-D 效应，包括： 1）基准面变化的 3-D 效应； 2）在近端盆地中传播活跃的褶皱，与盲目逆冲和渐进性不整合的发展有关； 3）结合横向和轴向排水的不对称半地堑中的沉积。 实验的主要成果将包括： 施加变量（水和沉积物供应、基准面和地下室地形）的时间记录；随时间变化的床面地形测量；流型、海岸线位置和其他表面特征的视频记录；由此产生的矿床的 3D 框图，以直接数字化（照片）和合成地震图像的形式呈现；以及所选剖面的合成地球物理测井数据。 合成地震是与现场观测的关键环节，因为研究人员获得与实验盆地生成的岩石记录相当的岩石记录视图的唯一方法是通过地震反射剖面过滤。 与实际的实验地层学相比，合成地震和测井记录也将增进我们对通过这些广泛使用的技术成像时岩石记录中保留和未保留的内容的理解。 实验结果将代表自 Pitman (1978) 海岸线对海平面变化响应模型以来开发的各种地层响应理论预测在完全受控条件下的首次测试。 他们还将提供一个模板，可以与基于地震和露头数据的现场观测和解释进行比较。 尽管实验室规模的模型永远无法捕获真实盆地中发生的所有复杂过程，但它们可以充当未经测试的理论模型和难以约束的自然实例之间的桥梁。