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

沉积盆地的海平面位置反映了三个因素之间的平衡：全球气候变化；影响泥沙积聚的环境内在因素；构造控制直接或间接地与板块边界动力学联系在一起。构造作用的从属作用是众所周知的，对于沿拖曳边缘或被动边缘的碳酸盐岩台地，但构造作用对沿会聚板块边界的前陆盆地台地地层学的潜在影响谱却不太明确。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以及在两个对比鲜明的前陆-盆地序列中形成的碳酸盐岩聚集模式。首先是渥太华盆地（安大略省东部），在该盆地中，中奥陶统至上奥陶统（4.6 - 4.5亿年）的热带碳酸盐台地的内部部分位于一个前陆盆地，该盆地定义了一个古老的（Taconic）火山弧后面的沉降历史。其次是南部盆地（巴塔哥尼亚），其中古近纪晚期-新近纪早期（26- 1500万年）的冷水碳酸盐岩薄层聚集在一个硅质前陆盆地内，该盆地主要定义了安第斯弧后的隆起。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机械弱化的下伏地壳可能在多大程度上额外影响了较年轻的盆地对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辐合带以外的当代盆地进行比较。这种方法将使我们更好地理解构造的规模和古地理广度，这些构造可以影响拥有冷水和温水碳酸盐岩系统的前陆盆地的沉积模式。

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.