Collaborative Research: Time of Transformation: integrating the dynamic geologic, climatic and biotic systems of North America during the Early to Late Cretaceous transition

从早白垩世到晚白垩世（约1.3亿至9000万年前）的过渡标志着陆地（陆基）生态系统的深刻变化。这些变化包括许多恐龙种群的灭绝和更替、开花植物和传粉昆虫的迅速增加、哺乳动物的多样性增加以及水生无脊椎动物的大量更替。陆地生态系统的这种戏剧性重组是在地貌和气候迅速变化的背景下发生的。这包括一条从内华达州延伸到蒙大拿州的山脉的上升，这导致了区域环境的变化，并对动物的运动形成了物理障碍。大规模的火山爆发导致气温和海平面上升，导致全球气候变暖，北美内陆被南北走向的海道淹没。这些环境变化保存在西部内陆盆地的沉积岩中，这是山脉以东的一个广泛沉积区。本项目将研究这些气候和构造变化与晚白垩世生态系统演化之间的因果关系。它将通过将时间校准的气候数据与跨越西部内陆盆地目标时间间隔和地理范围的几个重要岩层的详细化石出现相关联来完成。目的是确定气候和构造变化对陆地生命的进化、分布和灭绝的影响有多快。通过外展项目和博物馆展览的公众参与是这个项目的重要组成部分。北美早白垩世到晚白垩世的过渡（白垩纪中期）以深刻的动物群和植物群重组为标志，极大地改变了大陆生物多样性。这种生物的变化发生在地质事件和气候变化的背景下，在阿普第阶到赛诺曼阶的时间间隔，在坎帕尼亚-马斯特里赫特时代的高多样性植物群和动物群之前。北美西部内陆盆地因其纬度范围、相对完整的岩石序列和悠久的化石采集历史而成为研究白垩纪中期的典范。该项目将产生1）一个精细的大陆地层的年代框架（西部内陆盆地）; 2）古气候代用数据，以推断区域和全球气候趋势;和3）定量分析，将气候数据与关键地质事件结合起来，探索对区域范围内古群落重建的影响。结果将整合使用古生态位建模和规范对应分析与目标地层内的化石采样，以填补生物多样性数据的持续空白，并确定其对扩散，物种形成和营业额的影响。这项研究将产生大量的相关数据，以广泛的地球科学家社区调查西部内陆盆地，也可以帮助分析未来的气候状态。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

The transition from the Early to Late Cretaceous time period (~130 to 90 million years ago) was marked by profound changes to terrestrial (land-based) ecosystems. These included the extinction and replacement of many dinosaur groups, rapid increases in flowering-plants and pollinating insects, greater diversity of mammals, and major turnovers in aquatic invertebrates. This dramatic reorganization of terrestrial ecosystems occurred against a backdrop of rapid landscape and climatic changes. This includes the rise of a mountain chain running from Nevada through Montana that caused regional environmental changes and formed physical barriers to animal movement. Massive volcanic eruptions caused temperature and sea-level rises that ushered in a greenhouse global climate and flooding of the North American interior by a north-south trending seaway. These environmental changes are preserved within the sedimentary rocks of the Western Interior Basin, an extensive depositional area east of the mountains. This project will examine the cause-and-effect relationships between these climatic and tectonic changes and the evolution of the Late Cretaceous ecosystems. It will be accomplished by correlating time-calibrated climate data in conjunction with detailed fossil occurrences for several important rock formations that span the target time interval and geographic expanse of the Western Interior Basin. The goal is to determine how rapidly climatic and tectonic changes influenced the evolution, distribution, and extinction of land-based life. Public engagement through outreach programs and museum exhibits are an important component of this project.The Early to Late Cretaceous transition in North America (mid-Cretaceous) is marked by profound faunal and floral reorganization that dramatically altered continental biotas. Such biotic shifts occurred against a backdrop of geologic events and climatic changes during the Aptian to the Cenomanian time interval that preceded the high diversity flora and fauna of the Campanian-Maastrichtian Ages. The North American Western Interior Basin stands out as an exemplar for studying the mid-Cretaceous due to its latitudinal extent, relatively complete rock sequences, and long history of fossil collection. This project will generate 1) a refined chronologic framework for continental strata of the Western Interior Basin); 2) paleoclimatic proxy data to infer regional and global climate trends; and 3) quantitative analyses to integrate climate data with key geologic events that explore influences on paleo-community restructuring on a regional scale. Results will be integrated using paleoecological niche modeling and canonical correspondence analysis with fossil sampling within target formations to fill persistent gaps in biotic diversity data and to determine their effects on dispersal, speciation, and turnover. This research will generate a large body of data relevant to the broad community of geoscientists investigating the Western Interior Basin and could also help in the analysis of future climate states.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.