Paleozoic Biogeographic Signals from Southeastern Alaska

亚历山大像有着最长最完整的 阿拉斯加可疑火山岩的古生代地层， 地层和化石记录可以追溯到早期 奥陶纪 它位于几个年轻的海豚的外侧， 是理解增积的关键部分之一 北美洲西北部的历史。 许多工人相信 它的悠久历史始于西部的“原太平洋”， 在中生代晚期到达北美洲附近。 从正在进行的研究中获得的动物区系证据并不支持这一点 但这表明，亚历山大墓更接近 与北美大陆的联系比与 澳大利亚或亚洲。 这些动物群属于旧大陆领域， 主要表现出与安第斯山脉地区的亲缘关系， 澳大利亚东部和中国动物群的亲缘关系。 然而，在这方面， 亲和力并不完全是科迪尔式的， 西伯利亚方面需要进一步解释。 P.I.将收集并描述泥盆纪的腕足动物 密西西比和宾夕法尼亚的年代，看看这些是否也显示了 北美亲缘关系，或者如果它们表明一个持续的西伯利亚 影响力的社会 亚洲动物群知识的空白正在被 迅速被中国和苏联的工人填满， 一旦我们收集了足够的材料， 在我们自己的部门。 这项工作将集中在腕足动物， 因为它们是海底的，对水文因素很敏感， 但我们会利用我们最近对donodont的研究， 阿拉斯加东南部，因为这些提供了最好的年龄 控制这些石灰质的部分。

The Alexander terrane has the longest and most complete Paleozoic stratigraphy of the Alaskan suspect terranes, with a stratigraphic and fossil record extending back to the early Ordovician. It lies outboard of several younger terranes and it is one of the key sections in understanding the accretionary history of northwestern North America. Many workers believe it began its long history in the western "Protopacific" and only arrived in the vicinity of North America in late Mesozoic time. Faunal evidence gained from ongoing studies does not support this view but suggests that the Alexander terrane was more closely associated with the continent of North America than with Australia or Asia. The faunas belong to the Old World Realm and show mainly Cordilleran Region affinities that contrast with the affinities of faunas in eastern Australia and China. However, the affinities are not wholly Cordilleran and there are some Siberian aspects that need further explanation. P.I. will collect and describe brachiopods of Devonian, Mississippian, and Pennsylvanian age to see if these also show a North American affinity or if they indicate a continuing Siberian influence. The gaps in knowledge of Asiatic faunas are being rapidly filled by workers in China and the USSR so that comparisons are possible once we have collected adequate material in our own sections. The work will concentrate on brachiopods, because these are benthic and sensitive to biogeographic factors, but will make use of our recent work on donodonts from southeastern Alaska because these provide the best available age control in these calcareous sections.