Patterns of Carbonate Accumulation

碳酸盐堆积模式

• 批准号: 8803910
• 负责人: Bruce Wilkinson
• 金额: $ 12.3万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-09-01 至 1991-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8803910&HistoricalAwards=false
• 关键词: Patterns; Carbonate; Accumulation

Mass-age data on global sedimentary carbonates require that global limestone and dolostone comprise about 3,500 x 10^20 g of carbonate Ca with a cycling rate of 0.25% per million years. Epoch-interval deviations are small, suggesting relatively constant long-term rates of deposition and destruction. Best-fit curves through data on deep oceanic and shallow cratonic reservoirs indicate that shallow water limestone formation has been decreasing at a rate of about 0.7% per million years. Holocene shallow water limestone accumulation is not 60% lower than during the Mesozoic. Possible reasons for global carbonate transfer from shallow to deep setting are largely unconstrained. Biologically-medicated processes related to the Mesozoic diversification of planktic protozoans may have resulted in the progressive replacement of shallow shelly faunas by deep oceanic calcifiers as the principle sink for a finite marine carbonate flux. Conversely, decline of cratonic carbonate reservoir mass may reflect physicochemically- mediated processes related to global sea level and the extent of carbonate-saturated seas. Preliminary data indicate that ongoing carbonate transfer is also recorded by correlation between Cenozoic positions of the continents, global sea level, and the latitudinal extent of cratonic limestones. The project will: 1) compile global data on the areal extent, latitudinal setting, and vertical accumulation rates of shoal-water carbonate platforms; and 2) document relations between present patterns of shallow water carbonate accumulation and ambient fluid carbonate chemistry. Collectively, this effort will allow for the evaluation of relations between eustasy, ambient fluid saturation state, biological versus chemical precipitation processes, and global patterns of carbonate accumulation, and will directly constrain the history of surface carbonate saturation in shallow marine settings. This global data base will be of major importance to interpreting paleoclimate and understanding evolution of the ocean.

全球沉积碳酸盐岩的大量年龄数据要求， 全球石灰岩和白云岩约含3，500 x 10^20 g 碳酸盐钙，循环速率为每百万年0.25%。 时期间隔偏差很小，表明相对 沉积和破坏的长期恒定速率。 最适合 通过深海和浅海数据绘制的曲线 水库表明，浅水石灰岩地层 以每百万年0.7%的速度减少。 全新世浅水灰岩堆积不低60% 比中生代更早。 全球碳酸盐从浅水区迁移的可能原因 大部分是不受约束的。 生物药物 与中生代浮游生物多样化有关的过程 原生动物可能导致了 以深海钙化生物为原理， 有限海洋碳酸盐通量汇。 相反， 碳酸盐岩储集体可能反映了物理化学- 与全球海平面有关的介导过程以及 碳酸盐饱和的海洋 初步数据显示， 碳酸盐转移也记录了相关性之间 新生代大陆的位置、全球海平面和 南极灰岩的纬度范围。 该项目将：1）汇编关于该地区的全球数据， 范围，纬度设置和垂直积累率 浅水碳酸盐岩台地; 2）记录 目前浅水碳酸盐岩聚集的模式， 环境流体碳酸盐化学。 总的来说，这一努力将 允许评估环境、环境 流体饱和状态，生物沉淀与化学沉淀 过程和全球碳酸盐积累模式，并将 直接制约了地表碳酸盐饱和度的历史， 浅海环境 这一全球数据库将主要 解释古气候和理解 海洋的演变。