Bivalve Paleoecology: Key to the Environmental Stratigraphyof a Pliocene Sedimentary Sequence

在之前对新近纪晚期西大西洋双壳类生物地理、灭绝和系统演化模式的研究过程中，我广泛收集了佛罗里达州萨拉索塔上新世早期贝壳坑的动物群。该动物群因其丰富的种类(1000多种软体动物，其中约180种是双壳类)和良好的保存状态而壮观。在我的工作过程中，我得出的结论是，坑中的垂直相序记录了屏障-岛屿-泻湖复合体的海侵，这是瓦尔特定律的例证。这种类型的海侵层序在地层记录中很少见，因为海平面的快速相对上升通常会破坏障碍岛和泻湖相，或者导致它们向内陆跳跃。我正在开发一个模型来解释为什么海侵层序被保存在萨拉索塔--我认为这个模型具有普遍意义。这项提议是为了资助更详细地研究萨拉索塔坑的地层单位，更彻底地收集它们的动物群，以及充分开发地层模型。最终，我还将撰写一本关于整个双壳类动物群的分类-生物地理学专著，它代表了北方鲜有研究的著名动物群的时间等价物(佛罗里达州北部至弗吉尼亚州：杰克逊布拉夫、杜普林和约克镇动物群)。现在必须在萨拉索塔进行实地工作，因为矿坑很快就会被淹。

In the course of previous research on patterns of biogeography, extinction, and phyletic evolution for Western Atlantic Bivalvia during late Neogene time, I have made extensive collections of the early Pliocene fauna of a shell pit at Sarasota, Florida. This fauna is spectacular for its richness (more than a thousand species of mollusks, about 180 of them bivalves) and for its excellent state of preservation. In the course of my work, I have concluded that the vertical sequence of facies in the pit records the transgression of a barrier-island-lagoon complex, exemplifying Walther's Law. Transgressive sequences of this type are rare in the stratigraphic record because rapid relative rises of sea level usually destroy barrier island and lagoonal facies or cause them to jump inland. I am developing a model to explain why the transgressive sequence has been preserved at Sarasota - a model that I believe has general significance . This proposal is for funding to support more detailed study of the stratigraphic units in the Sarasota pit, more thorough collection of their faunas, and full development of the stratigraphic model. Ultimately, I will also produce a taxonomic-biogeographic monograph on the total bivalve fauna, which represents the little-studied temporal equivalent of well-known faunas to the north (northern Florida to Virginia: the Jackson Bluff, Duplin and Yorktown faunas). It is crucial that the field work in Sarasota be conducted now because the pit will soon be flooded.