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气体变暖的长时间无冰时期，但越来越多的人意识到，温暖的气候可能已经被更凉爽的时期和冰的积累所打断。克罗地亚的古迪纳里亚台地是7公里厚的碳酸盐台地，就像巴哈马群岛一样。然而，由于抬升，其关于全球气候变化的出色沉积记录在地表暴露出来，无需深部钻探即可研究。浅水平台记录了5000万年来侏罗纪晚期和白垩纪早期(1.5亿至1亿年前)的许多海平面波动，可以用来定义温室时期，当时地球没有冰盖，海平面经历了许多小的海平面波动，以及当地球有中等大小的冰盖时的过渡时期，以及较少但较大的海平面变化(小冰盖的消长)。该项目将记录来自沉积序列的海平面和气候变化的频率和幅度。化石，锶同位素将被用来确定序列的时间，碳和氧的稳定同位素将被用来记录生物生产的变化，有机碳的埋藏，以及小冰盖可能的消长。对海平面变化的估计将使用计算机模拟地层学，这将使我们能够极大地精炼这段时间内的气候变化。该项目将增加我们对全球温室效应时期全球气候变化的了解，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.