COLLABORATIVE RESEARCH: Time-Averaging in Mixed Brachiopod- Mollusk Assemblages along a Depth Gradient across a Modern Tropical Shelf

合作研究：现代热带大陆架上沿深度梯度的混合腕足动物-软体动物组合的时间平均

• 批准号: 0124767
• 负责人: John Wehmiller
• 金额: $ 5.43万
• 依托单位: George Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-01 至 2004-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0124767&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Time; Averaging; Mixed

The limits to temporal resolution imposed by processes of time-averaging (i.e., age mixing of fossils that determines the temporal resolution of the fossil record) have broad implications for interpretation of the fossil record in a wide variety of types of studies. Almost no information on time-averaging is currently available for brachiopods, the predominant organism comprising Paleozoic and many later marine shell assemblages. We propose to use a combination of amino acid racemization and radiocarbon dating to document time-averaging in surficial accumulations of mixed brachiopod-mollusk shells on the southern Brazilian shelf. The resulting data will provide quantitative estimates of age structures of dated shells of brachiopods and mollusks from seven sites along a depth gradient. The study is expected to produce (1) the first quantitative estimates of time-averaging for brachiopod shell accumulations, (2) the first comparative data on time-averaging for two groups of biomineralized organisms (brachiopods vs. mollusks), and (3) the first estimates of time-averaging along an onshore-offshore bathymetric gradient. By adding taxonomic and environmental dimensions to the current knowledge of time-averaging, this study will provide a significant contribution to our understanding of the temporal resolution of the fossil record.

通过时间平衡过程（即确定化石记录的时间分辨率的化石的年龄混合）施加的时间分辨率的限制对解释化石记录的解释具有广泛的影响。 目前，几乎没有关于腕足动物，包括古生代和许多后来的海洋壳体组合的主要有机体。 我们建议将氨基酸种族化和放射性碳历来的结合使用，以记录巴西南部架子上混合腕足动物壳的表面积累中的时间平均水平。 最终的数据将提供沿深度梯度的七个地点的甲虫和软体动物的年龄结构的定量估计。预计这项研究将产生（1）对金属甲甲状腺壳积累的时间平均时间的第一个定量估计，（2）两组生物矿化生物体（Brachiopods vs. Mollusks）的时间平均值的第一个比较数据，以及（3）（3）沿上沿层次上的浴室浴室的第一个估计值。通过将分类学和环境维度添加到当前的时间平衡知识中，这项研究将为我们对化石记录的时间分辨率做出重大贡献。