Collaborative Research: Integrated Field and Laboratory Studies of Foraminiferal Taphonomy in Quaternary Carbonate and Siliclastic Depositional Environments

加利福尼亚州海湾北部第四纪硅质碎屑沉积物中有孔虫的化石蚀变将通过野外和实验室对耐磨性、溶蚀、生物侵蚀和运输的测试研究来量化。全新世和更新世沉积物的紧密并列将使人们能够评估从活的有孔虫生物群到近地表沉积物组合到保存下来的化石组合的转化过程。这种方法的好处包括：1)识别在特定环境制度下积累的组合中占主导地位的测试形态类型。2)测试攻丝标记的保存性。3)结合活体物种相对丰度和试验生产率的数据，确定种群动态和挖掘过程对沉积物组合形成的相对贡献。4)确定赋予抗破坏能力的试验特征具有重要的进化意义，并应有助于更好地理解对特定环境的形态限制。上述信息将与以前从牙买加全新世碳酸盐环境中获得的信息结合起来，从而开发出涵盖广泛的微化石组合的墓葬相模型。由于这些模型是基于测试形态类型，而不是特定的物种，它们应该适用于多种环境和时间间隔。

Taphonomic alteration of foraminifera from Quaternary siliciclastic deposits in the northern Gulf of California will be quantified through field and laboratory studies of test resistance to abrasion, dissolution, bioerosion, and transport. The close juxtaposition of Holocene and Pleistocene deposits will allow the evaluation of those processes involved in the transformation from living foraminiferal biotas through near-surface sediment assemblages to preserved fossil assemblages. The benefits from such an approach include: 1) The identification of test morphotypes which predominate within assemblages accumulating under particular environmental regimes. 2) Testing of the preservability of taphonomic signatures. 3) When combined with data on the relative abundances of living species and test production rates, the determination of the relative contributions of population dynamics and taphonomic processes to the formation of sediment assemblages. 4)The determination of test characteristics which confer resistance to destruction has important evolutionary implications and should lead to the better understanding of the morphological constraints on inhabiting particular environments. The above information will be integrated with that obtained previously from Holocene carbonate environments at Jamaica, resulting in the development of broadly encompassing taphofacies models for microfossil assemblages. As these models are based upon test morphotypes, rather than particular species, they should be applicable to numerous environments and time intervals.