ROW: Paleoecologic and Paleobiogeographic Analysis of the Heceta Limestone, Alexander Terrane, Southeastern Alaska

该项目将调查赫切塔石灰岩，这是一个保存在阿拉斯加东南部古老岛弧序列中的早志留世-晚志留纪时代的沉积物。这种形成发生在亚历山大地体内，亚历山大地体是构成北美西部大陆边缘的许多吸积地体之一。这项研究的一个主要目标是确定赫切塔石灰岩所代表的沉积环境。岩相和生物相的记录将基于岩石学、岩相学和古生物学数据，这些数据来自主要在赫切塔、科斯丘斯科、大理石、奥尔、塔克斯坎和威尔士亲王群岛收集的岩石样本和化石。该项目的另一个主要目标是确定保存下来的大型无脊椎动物种群的古生态，特别是腕足类占主导地位的群落，以及这些动物群的古地理亲缘关系。开发一个模型来解释赫切塔石灰岩中化石组合的省级亲缘关系，以及这些动物群所居住的古环境的演变，应该有助于完善我们对保存在阿拉斯加东南部的岛弧系统的理解。拟议研究的结果还应有助于更全面地确定该区域的大地构造史，并有助于更好地评估亚历山大地体的古地理和古生物地理重建。

This project will investigate the Heceta Limestone, which is a deposit of Early-Late Silurian age preserved within an ancient island arc sequence in southeastern Alaska. This formation occurs within the Alexander Terrane, which is one of the many accretionary terranes forming part of the continental margin of western North America. A main objective of this research is to determine the depositional environments represented in the Heceta Limestone. Documentation of the lithofacies and biofacies will be based on petrologic, petrographic, and paleontologic data derived from rock samples and fossils collected mainly on Heceta, Kosciusko, Marble, Orr, Tuxecan, and Prince of Wales Islands. Another major goal of this project is to determine the paleoecology of the preserved macroinvertebrate populations, in particular the brachiopod- dominated communities, and the paleobiogeographic affinities of these faunas. The development of a model that explains the provincial affinities of the fossil assemblages that occur in the Heceta Limestone and the evolution of the paleoenvironments these faunas inhabited should aid in refining our understanding of the island arc system preserved in southeastern Alaska. The results of the proposed research should also help to define more completely the geotectonic history of the region and lead to a better assessment of paleogeographic and paleobiogeographic reconstructions of the Alexander Terrane.