Joint U.S.-Croatian Cooperative Research Project: Greenhouse and Transitional Climates in 50 m.y. Carbonate Record of the Late Jurassic-Early Cretaceous Dinaric Platform Croatia

地球科学家倾向于将中生代视为全球温室变暖的长期无冰时期，但越来越多的人意识到，温暖的气候可能被较冷的时期和冰的积聚所打断。古老的迪纳里克台地，克罗地亚是一个7公里厚的碳酸盐岩台地，像巴哈马一样。然而，由于隆起，其极好的全球气候变化沉积记录暴露在地表，无需深入钻探即可进行研究。浅水台地记录了5000万年的晚侏罗世和早白垩纪（1.5亿至1亿年前）的许多海平面波动，可以用来定义地球缺乏冰盖和海平面经历许多小海平面波动的温室时代，以及地球有中等大小的冰盖，较少但较大的海平面变化（小冰盖的盛衰）的过渡时期。该项目将记录由沉积演替引起的海平面和气候变化的频率和幅度。化石和锶同位素将用于确定演替的年代，碳和氧的稳定同位素将用于记录生物生产的变化、有机碳的埋藏以及小冰盖可能的盛衰。我们将利用计算机模拟地层学来估计海平面的变化，这将使我们能够大大改进这一时期的气候变化。该项目将增加我们对全球温室时期全球气候变化的认识，以及向较冷阶段过渡的模式。

Geoscientists have tended to view the Mesozoic as a long ice-free time of global greenhouse warmth, but there is increasing awareness that the warm climate may have been interrupted by cooler periods and ice buildup. The ancient Dinaric Platform, Croatia is 7 km thick carbonate platform like the Bahamas. However because of uplift, its superb sedimentary record of global climate change is exposed at the surface and can be studied without deep drilling. The shallow water platform recorded many of the sea level fluctuations of the 50 million year Late Jurassic and Early Cretaceous (150 to 100 million years ago), and can be used to define greenhouse times when the earth lacked ice sheets and sea levels underwent many small sea level fluctuations, and times of transition when the earth had moderate sized ice sheets, and fewer, but larger sea level changes (waxing and waning of small ice sheets). The project will document the frequency and magnitude of sea level and climate change from the sedimentary succession. Fossils, and Sr isotopes will be used to date the succession and stable isotopes of carbon and oxygen will be used to document changes in biologic production, burial of organic carbon, and possible waxing and waning of small ice sheets. Estimates of sea level changes will be made using computer simulations of the stratigraphy, which will allow us to greatly refine the climate changes during this time period. The project should increase our understanding of global climate change during times of global greenhouse, and mode of transitions into cooler phases.