A New Approach for Evaluating Controls on Depositional Sequence Architecture

评价沉积层序结构控制的新方法

• 批准号: 9527004
• 负责人: Evan Franseen
• 金额: $ 13.8万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-15 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9527004&HistoricalAwards=false
• 关键词: New; Approach; Evaluating; Controls; Depositional

Franseen 9527004 For the past decade, concepts of sequence stratigraphy have been applied to studies of carbonate facies. However, in large part, our understanding of the variable that control the location and geometry carbonate depositional sequences are inadequate because of the few studies that are able to isolate these variables. The objectives of this study are to evaluate the effect of variables such as eustatic sea level fluctuation, regional sea level fluctuation, tectonism, substrate paleoslope, leeward versus windward location, siliciclastic input and autogenic controls, by using a unique combination of quantified relative sea level histories, high resolution chronostratigraphic correlations, and selection of localities which allow isolation of different variables. We have selected the Upper Miocene because of exceptional exposures of Upper Miocene carbonate sequences from Mediterranean region. The comparison of shapes and magnitudes of relative sea level fluctuations shown on quantitative relative sea level curves from different areas, combined with field data and high resolution age control from radiometric dating, biostratigraphy and magnetostratigraphy, can provide the detailed data necessary to determine the effects of local, regional and global controls on depositional sequence development. To arrive at the overall goal the proposed project is divided into four phases. Phase I is complete. It was designed to develop a quantitative record of the relative sea level history, chronostratigraphy, and to develop a detailed understanding of the sequence stratigraphy for one locality. It has developed a new method for quantification of relative sea level history (pinning points) based on identification of facies deposited at or just below sea level and on tracing evidence of subaerial exposure on marine rocks down paleoslope. It has also produced a high resolution chronostratigraphy calibrated with radiometric dates. The successful completion of Phase I of this project h as already illustrated significant deviations from commonly accepted sequence stratigraphic models by showing the importance of substrate paleoslope and illustrating that the architecture predicted by the systems tract approach is not applicable. Funding is requested for Phase II and Phase III in this proposal. Phase II will develop the same information as in Phase I in separate localities on the same tectonic block. This information includes geologic mapping, petrography, construction of pinning point curve, magnetostratigraphy, biostratigraphy, and radiometric dating. Time correlation of depositional sequences between the areas will allow the analysis of local variables such as substrate paleoslope, leeward versus windward location, siliciclastic input and autogenic controls while the variable of relative sea level should be held relatively constant because of the location on the same tectonic block. Phase III involves working with other researchers who are studying areas on separate tectonic blocks of the Mediterranean to develop similar quantitative relative sea level histories, chronostratigraphy and sequence stratigraphy in those locations. This comparison will allow analyses of the tectonic effects on relative sea level history and sequence stratigraphy in unites that have experienced the same overall Mediterranean sea level history. Phase IV is the final phase of the study. It will develop similar quantitative relative sea level histories, chronostatigraphy and sequence stratigraphy for sites outside of the Mediterranean to separate local Mediterranean sea level effects from eustatic effects. The purpose of this research is to develop an understanding of the variables that control the location and architecture of carbonate depositional sequences. Thus, the product will be a quantitative understanding of how depositional sequence geometry, location, and facies distribution is controlled by: (1) local variables of paleoslope, autogenic controls, siliciclastic input, and seaw ard versus windward location; (2) regional variables of tectonic controls on accommodation space and Mediterranean sea level, and (3) global sea level. Once the sedimentologic effect of these variables are understood , a better general understanding of the geologic record may be gained, and predictive models may be refined to the point of aiding oil and gas production.

法兰森9527004 在过去的十年里，层序地层学的概念已被应用于碳酸盐岩相的研究。 然而，在很大程度上，我们对控制碳酸盐沉积序列的位置和几何形状的变量的理解是不够的，因为很少有研究能够隔离这些变量。 本研究的目的是评估变量的影响，如海平面波动，区域海平面波动，构造作用，基板古坡度，背风与迎风位置，硅质岩输入和自生控制，通过使用一个独特的组合量化的相对海平面的历史，高分辨率年代地层对比，并选择允许隔离不同的变量的地点。 我们之所以选择上中新统，是因为地中海地区上中新统碳酸盐岩序列的特殊暴露。 比较不同地区定量相对海平面曲线上所显示的相对海平面波动的形状和幅度，再加上实地数据和来自放射性测年、生物地层学和磁性地层学的高分辨率年龄控制，可以提供确定局部、区域和全球控制因素对沉积层序发育的影响所必需的详细数据。 为实现总体目标，拟议项目分为四个阶段。 第一阶段已经完成。 它的目的是发展相对海平面历史的定量记录，年代地层学，并发展一个地方的层序地层学的详细了解。 它根据海平面或略低于海平面的沉积相的识别和古斜坡下海相岩石陆上暴露的追踪证据，开发了一种新的量化相对海平面历史（钉扎点）的方法。 它还制作了一个高分辨率的年代地层学，用放射性测年法进行了校准。 该项目第一阶段的成功完成已经说明了与普遍接受的层序地层模型的重大偏差，表明了基底古斜坡的重要性，并说明了体系域方法预测的体系结构不适用。 本提案要求为第二阶段和第三阶段提供资金。 第二阶段将在同一构造块的不同地点开发与第一阶段相同的信息。 这些信息包括地质填图、岩石学、构造钉扎点曲线、磁性地层学、生物地层学和放射性测年。 区域之间沉积序列的时间相关性将允许分析局部变量，如基底古坡度、背风与迎风位置、硅质岩输入和自生控制，而相对海平面变量应保持相对恒定，因为它们位于同一构造块体上。 第三阶段涉及与研究地中海不同构造块区的其他研究人员合作，在这些地点开发类似的定量相对海平面历史、年代地层学和层序地层学。 这种比较将允许在经历了相同的整体地中海海平面历史的单元中分析构造对相对海平面历史和层序地层学的影响。 IV期是研究的最后阶段。 它将为地中海以外的地点开发类似的定量相对海平面历史、年代统计学和层序地层学，以将当地地中海海平面影响与海平面变化影响分开。 本研究的目的是了解控制碳酸盐岩沉积序列的位置和结构的变量。 因此，该产品将是对沉积层序几何形状、位置和相分布如何受以下因素控制的定量理解：（1）古坡度、自生控制、硅质岩输入和向海与迎风位置的局部变量;（2）构造对可容纳空间和地中海海平面的控制的区域变量;（3）全球海平面。 一旦了解了这些变量的沉积学效应，就可以对地质记录有更好的总体了解，并且可以将预测模型改进到有助于石油和天然气生产的程度。