Nontectonic influences on continental basin-fill sedimenta- tion and post-orogenic sedimentation in a late Cenozoic Extensional Basin

非构造对晚新生代伸展盆地陆相盆地充填沉积和造山后沉积的影响

• 批准号: 8916355
• 负责人: Gary Smith
• 金额: $ 10万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-02-01 至 1993-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8916355&HistoricalAwards=false
• 关键词: Nontectonic; influences; continental; basin; fill

The project will evaluate the sedimentology and stratigraphy of the Pliocene-early Pleistocene St. David Formation in southeastern Arizona. The St. David Formation was deposited in a Basin and Range valley after near cessation of relative motion between range fronts and valley floor. This setting allows for examination of the characteristics of basin sedimentation in the absence of active deformation along the basin margins. Preliminary study reveals an approximately 150 m thick coarsening-upward sequence with considerable vertical and lateral variability. In the absence of active tectonism, temporal changes in depositional style must be caused by climatic changes and evolving drainage patterns related to regional drainage integration. Some of these changes are tentatively correlated to marine paleoclimatic records. This project represents the first concerted effort to evaluate the sedimentology of a largely pre- Quaternary continental basin-fill unit with emphasis on climate and paleogeomorphological changes, rather than tectonism, to produce temporal and spatial variations in sediment grain size and facies distribution. The results will be used to a) charactertize the nature of late-stage basin sedimentation, b) evaluate the validity of current hypotheses relating stratigraphic variation, apriori, to episodic tectonism, and c) attempt correlation of a Pliocene-early Pleistocene nonglacial continental record to marine paleoclimatic records.

该项目将评估亚利桑那州东南部上新世-早更新世圣大卫组的沉积学和地层学。在山前和谷底之间的相对运动几乎停止后，圣大卫组沉积在盆地和山脉谷地中。这一设置允许在盆地边缘没有活动变形的情况下检查盆地沉积的特征。初步研究揭示了一个厚约150米的粗化-向上层序，具有相当大的垂直和横向变化。在没有活动构造作用的情况下，沉积样式的时间变化必然是由气候变化和与区域水系一体化有关的水系模式演变引起的。其中一些变化与海洋古气候记录初步相关。该项目是第一次共同努力评估一个主要是第四纪以前的大陆盆地充填单元的沉积学，重点是气候和古地貌变化，而不是构造作用，以产生沉积物粒度和相分布的时空变化。这些结果将被用来a)表征晚期盆地沉积的性质，b)评估当前将地层变化先验地与幕式构造作用联系起来的假设的有效性，以及c)尝试将上新世-早更新世非冰川大陆记录与海洋古气候记录进行对比。