Physical modelling of climatic control on multistage fan-delta progradation

多阶段扇三角洲进积气候控制物理模型

• 批准号: 38787162
• 负责人: Dr. Johan H. ten Veen
• 金额: --
• 依托单位: TNO.NL - Netherlands Institute of Applied Geoscience
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2009-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/38787162?language=en
• 关键词: Physical; modelling; climatic; control; multistage

The Sitia Basin (Crete, Greece) comprises an Upper Miocene basin fill that is characterized by prograding fan-delta bodies at the margin and hemipelagic muds in the centre. These muds display an alternation of marls and sapropels, which is also reflected in the clay mineralogy by means of gamma-ray spectrometry. Biostratigraphy enables correlation of high-order variations in gamma-ray intensity with the 20 kyr astronomical cycle of precession. Lower order variations correlate with the 100 kyr cycle of eccentricity. The presence of key beds allows correlation of the basin margin and -centre successions. This correlation suggests that progradational delta bodies have a frequency of 100 kyr and correspond with maxima in the eccentricity cycle. Therefore, we propose that fan-delta formation is triggered by increased surface run-off during wetter periods at this frequency. However, the extent to which these climate variations control deposition is only poorly understood. In order to further test our hypothesis and to quantify the effects of various Milankovitch cycles on fan delta behaviour we propose to perform physical, scaled experiments in the “EUROTANK” flume tank facility. The outcome of these experiments will give insight into the sensitivity and timedependency of sink-to-source systems toward different orders of discharge fluctuations.

锡蒂亚盆地（希腊克里特岛）由上中新世盆地填充物组成，其特征是边缘有进积的扇三角洲体，中心有半远洋泥浆，这些泥浆显示出泥灰岩和腐泥的交替变化，这也反映在粘土中。通过伽马射线光谱测量的矿物学能够将伽马射线强度的高阶变化与 20 kyr 天文周期相关联。低阶变化与 100 kyr 的偏心率周期相关。关键层的存在使得盆地边缘和中心序列具有相关性，这种相关性表明进积三角洲体的频率为 100 kyr，并且与偏心率的最大值相对应。因此，我们认为扇三角洲的形成是由湿润时期地表径流增加引发的，但我们对这些气候变化控制沉积的程度知之甚少。假设并量化各种米兰科维奇循环对扇三角洲行为的影响，我们建议在“EUROTANK”水槽设施中进行物理规模实验，这些实验的结果将深入了解汇到源的敏感性和时间依赖性。系统朝向不同的排放波动顺序。