A comparative analysis of the tetonic response of warm and cool water carbonate platforms in contrasting retroarc foreland basins

对比弧后前陆盆地温水和冷水碳酸盐台地的构造响应对比分析

• 批准号: 137517-2011
• 负责人: Dix, George
• 金额: $ 1.6万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=507596
• 关键词: comparative; analysis; tetonic; response; warm

The position of sea level in a sedimentary basin reflects a balance among three factors: global changes in climate; environmentally intrinsic factors that influence sediment accumulation; and tectonic controls linked directly and indirectly to plate-boundary dynamics. The subordinant role of tectonism is well known for carbonate platforms along trailing or passive margins, but the potential spectrum of tectonic influences on platform stratigraphy within foreland basins along convergent plate boundaries is less well defined. The proposed research, to include both outcrop, core, and laboratory analyses, will examine the geological record of tectonic influence and the resulting patterns of carbonate accumulation within two contrasting foreland-basin successions. First, the the Ottawa Embayment (eastern Ontario), within which a Middle to Upper Ordovician (460-450 million years) interior portion of a tropical carbonate platform lay in a foreland basin that defines a history of subsidence behind an ancient (Taconic) volcanic arc. Second, the Austral Basin (Patagonia), within which thin accumulations of cool-water carbonates of late Paleogene-early Neogene (26-15 million years) age occur within a siliciclastic foreland basin that defines mostly uplift behind an Andean arc. The first basin also overlies an ancient continental rift system, and several intrabasinal projects will examine to what extent the mechanically weakened underlying crust may have additionally influenced the younger basin's response to distal plate-boundary convergence. A detailed sequence stratigraphic framework for each foreland platform succession will be compared with contemporary basins that lay beyond the zone of convergence. This approach will allow an improved understanding of the scales and paleogeographic breadth of tectonics that can influence sedimentation patterns in foreland basins hosting cool- and warm-water carbonate systems.

海平面在沉积盆地中的位置反映了三个因素之间的平衡：全球气候变化;影响沉积物积累的环境内在因素;直接和间接与板块边界动力学有关的构造控制。对于沿着后缘或被动边缘的碳酸盐岩台地，构造作用的从属作用是众所周知的，但构造作用对沿着会聚板块边界的前陆盆地内台地地层的潜在影响范围则不太明确。拟议的研究，包括露头，岩心和实验室分析，将检查构造影响的地质记录和由此产生的模式碳酸盐积累在两个对比的前陆盆地序列。首先是渥太华湾（安大略东部），其中一个中奥陶纪至上奥陶纪（4.6亿~ 4.5亿年）的热带碳酸盐台地的内部部分位于前陆盆地中，该盆地确定了古（塔科尼）火山弧后的沉降历史。第二，南部盆地（巴塔哥尼亚），其中古近纪晚期-新近纪早期（2600 - 1500万年）的冷水碳酸盐的薄积累发生在硅质前陆盆地内，该盆地主要是安第斯弧后的隆起。第一个盆地还覆盖着一个古老的大陆裂谷系统，几个盆地内项目将研究在何种程度上机械弱化的底层地壳可能会影响年轻的盆地的远端板块边界收敛的反应。每个前陆台地序列的详细层序地层格架将与位于会聚带之外的当代盆地进行比较。这种方法将允许一个更好的理解的规模和古地理宽度的构造，可以影响沉积模式的前陆盆地托管冷水和热水碳酸盐系统。