Calibration of Geologic Cycling Rate

地质循环率的校准

• 批准号: 9902849
• 负责人: Bruce Wilkinson
• 金额: $ 13.48万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2003-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902849&HistoricalAwards=false
• 关键词: Calibration; Geologic; Cycling; Rate

9902849WilkinsonAvailable data on ages, areas, thicknesses, and volumes of sedimentary rock on continents, and on ages and areas of sedimentary rock actually exposed at the Earth's surface, indicate that decrease in map area with increasing age takes place almost an order of magnitude faster than decrease in total sequence area or volume. This difference reflects the fact that map area is "destroyed" both by erosion and burial by younger units, whereas total reservoir extent is only modified by erosion. The difference however,allows for direct estimation of decreasing intensity of cycling rate as a function of increasing sequence age. At present, estimates of total reservoir size on all continents except Antarctica are adequate to discriminate eon-scale rates of destruction. Conversely, data on areas and ages of exposed sedimentary, igneous, and metamorphic reservoirs have only been coarsely determined, and significant improvement in the precision of these estimates can be accomplished with a modest amount of effort.Therefore, we will compile a global database on areas and ages of exposed rocks from the most currently available geological maps of the Earth, and major continental land masses. Many of these recently released compilations are in digital format and are amenable to quantitative evaluation using commercially available software packages. Results ofthese efforts will embody age-corrected assessment of epoch-scale rates of rock cycling on continental crust, as well as estimates of secular variation in cycling rate as a function of global eustasy, tectonic setting, and paleolatitude.

[902849]现有的关于大陆上沉积岩的年龄、面积、厚度和体积的资料，以及关于地球表面实际暴露的沉积岩的年龄和面积的资料表明，随着年龄的增加，地图面积的减少速度几乎比总层序面积或体积的减少快一个数量级。这种差异反映了这样一个事实，即地图区域受到侵蚀和较年轻单元的埋藏的“破坏”，而总的储集范围只受到侵蚀的改变。然而，不同之处在于，可以直接估计循环率随层序年龄的增加而降低的强度。目前，对除南极洲以外所有大陆上水库总规模的估计足以区分亿尺度的破坏速度。相反，关于暴露的沉积、火成岩和变质岩储层的面积和年龄的数据只是粗略地确定了，而且这些估计的精度可以通过适度的努力来实现显著的提高。因此，我们将从目前可获得的地球和主要大陆块的地质图中编制一个关于裸露岩石的区域和年龄的全球数据库。这些最近发布的汇编中有许多是数字格式的，可以使用商业上可用的软件包进行定量评价。这些努力的结果将包括对大陆地壳上岩石循环的年代尺度速率的年龄校正评估，以及对循环速率的长期变化的估计，该变化是全球海洋起伏、构造环境和古纬度的函数。