权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Inoceramid sclerochronology - Advancing Late Cretaceous climate reconstructions

Inoceramide 硬化年代学 - 推进晚白垩世气候重建

基本信息

批准号：
281516390
负责人：
Professor Dr. Bernd R. Schöne
金额：
--
依托单位：
Institut für Geowissenschaften
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2015
资助国家：
德国
起止时间：
2014-12-31 至 2020-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/281516390?language=en
关键词：
Inoceramid sclerochronology Advancing Late Cretaceous

项目摘要

The Cretaceous serves a classic example of a greenhouse world and belongs to one of the best studied time intervals of Earth history. However, it still remains uncertain which actual temperatures prevailed at different latitudes and water depths, and almost nothing is known about the seasonal and inter-annual environmental variability in extratropical oceans at that time. Such information is essential to constrain meridional temperature gradients, verify the presence or absence of polar ice, test hypotheses on atmospheric and oceanic circulation patterns and further refine numerical climate models. It may also be used to study the link between sedimentation and orbital forcing in more detail, because the latter modifies seasonal temperature patterns. Furthermore, high-resolution temperature (and other environmental) data can help to better understand species distribution patterns, the paleobiology and life history traits of organisms as well as potential causes for the rise and demise of taxa. A promising archive for deciphering seasonal to inter-annual climate dynamics in extratropical Cretaceous oceans - whose full potential has by far not been explored - is contained in shells of inoceramid bivalves. This peculiar species-group appeared in the Permian and, for yet unknown reasons, became extinct several million years prior to the Cretaceous/Paleogene boundary. Despite decades of research, not particularly much is known about the biology, ecology and life-history traits of the inoceramids, but they thrived in the greenhouse climate of the late Mesozoic. During the Late Cretaceous, they clearly dominated the extratropical megafauna. With enormous shell sizes of up to 3m (!), inoceramids belong to the largest bivalves that ever lived. Inoceramids inhabited nearly any water depth and even occurred abundantly in hostile, dysoxic environments. By applying state-of-the-art sclerochronological techniques combined with a broad spectrum of diagenesis screening tests, the proposed study will pave the way toward a routine use of inoceramid bivalves in high-resolution paleoclimatology. To demonstrate the potential of this archive, we will exemplarily study how seasonal temperatures changed (1) during the Cretaceous hothouse, i.e. before, during and after OAE2 (Cenomanian/Turonian stage boundary; Münsterland Basin) and (2) during the Campanian stage (Hokkaido). (3) In addition, it will be analyzed if a difference exists between seasonal environmental variables reconstructed from shells of different rock types (Münsterland Basin). If sedimentation was orbitally forced, seasonal temperatures, primary productivity etc. should have differed between times of limestone and marl deposition. (4) Furthermore, the life history traits of selected inoceramid taxa will be determined including ontogenetic ages as well as the timing and rate of seasonal shell growth.

白垩纪是温室世界的典型例子，也是地球历史上研究得最好的时期之一。然而，在不同的纬度和水深，实际温度占主导地位仍然是不确定的，而且对当时温带海洋的季节和年际环境变化几乎一无所知。这些信息对于限制经向温度梯度、核实极地冰的存在与否、检验关于大气和海洋环流模式的假设以及进一步完善数值气候模式是必不可少的。它也可以用来更详细地研究沉降和轨道强迫之间的联系，因为后者会改变季节温度模式。此外，高分辨率的温度（和其他环境）数据有助于更好地了解物种分布模式，生物的古生物学和生活史特征以及分类群兴起和消亡的潜在原因。在白垩纪温带海洋中，破译季节到年际气候动态的一个很有希望的档案——其全部潜力迄今尚未被探索——包含在双壳类双壳类的壳中。这个奇特的物种群出现在二叠纪，由于未知的原因，在白垩纪/古近纪界线之前几百万年就灭绝了。尽管经过数十年的研究，人们对接种虫的生物学、生态学和生活史特征所知不多，但它们在中生代晚期的温室气候中茁壮成长。在晚白垩纪，它们明显统治了温带巨型动物。由于其巨大的外壳尺寸可达3米，它属于有史以来最大的双壳类动物。鱿鱼类几乎可以在任何水深生存，甚至大量出现在恶劣的、缺氧的环境中。通过将最先进的年代技术与广泛的成岩筛选试验相结合，拟议的研究将为在高分辨率古气候学中常规使用接种壳双壳类铺平道路。为了证明该档案的潜力，我们将举例研究(1)白垩纪温室期间，即OAE2 （Cenomanian/Turonian阶段边界；m<s:1> nsterland盆地）之前，期间和之后的季节温度变化(2)坎帕尼亚阶段（北海道）。(3)分析不同岩石类型（m<s:1> nsterland盆地）贝壳重构的季节环境变量是否存在差异。如果沉积是轨道强迫的，那么季节温度、初级生产力等在石灰岩和泥灰岩沉积时期应该是不同的。(4)此外，还将确定所选接种螺群的生活史特征，包括个体发生年龄以及季节壳生长的时间和速率。