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

加利福尼亚湾北部第四纪硅酸碎屑沉积物中有孔虫的地层蚀变将通过实地和实验室的耐磨性、溶解性、生物侵蚀性和迁移性测试研究进行量化。全新世和更新世沉积物的紧密并置将使我们能够评估从活的有孔虫生物群通过近地表沉积物组合到保存的化石组合的转变过程。这种方法的好处包括：1)鉴定在特定环境条件下积累的组合中占主导地位的测试形态。2)埋藏学特征的保存性检验。3)结合现存物种相对丰度和试验产量数据，确定种群动态和地学过程对沉积物组合形成的相对贡献。4)确定具有抗破坏能力的测试特征具有重要的进化意义，并应有助于更好地理解居住在特定环境中的形态限制。上述信息将与先前从牙买加全新世碳酸盐环境中获得的信息相结合，从而开发出广泛涵盖微化石组合的接触相模型。由于这些模型是基于测试形态，而不是特定的物种，它们应该适用于许多环境和时间间隔。

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.