Bed-scale characteristics and microfacies of Eocene-Miocene bottom-current deposits on Cyprus: Diagnostic criteria for contourite identification and drift-related spatial facies trends

塞浦路斯始新世-中新世底流沉积物的层尺度特征和微相：等高线识别和漂移相关空间相趋势的诊断标准

• 批准号: 461375233
• 负责人: Professor Dr. Heiko Hüneke
• 金额: --
• 依托单位: Institut für Geologie, Mineralogie und Geophysik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/461375233?language=en
• 关键词: Bed; scale; characteristics; microfacies; Eocene

The interaction of along-slope and down-slope marine sedimentary flow processes, resulting in the accumulation of interbedded contourites, turbidites and associated deep-water facies, has been well documented on many modern continental margins. However, despite many decades of research, the nature of this interaction and, in particular, the distinction between different facies types remains poorly understood. In fact, there is still much controversy over the criteria by which contourites, especially coarser (sandy) contourites, can be identified and distinguished from turbidites.This project aims to investigate calcareous contourites and associated deep-marine facies from an Eocene-Miocene continental slope succession on Cyprus. Because of its excellent and easily accessible exposure, as well as the clear evidence for deposition by along-slope bottom currents, the Circum Troodos sedimentary record is a prototype example of ancient contourites exposed on land. In a first step, we assess the drift type and the 3D geometry and establish a regional facies model of the carbonate contourite depositional system on Cyprus. This large-scale geometric assessment will be based on onshore digital terrain and outcrop models as well as offshore seismic data. In a second step, we critically evaluate and improve existing facies models for carbonate contourites and bottom-current reworked carbonate turbidites. These investigations at the bed-scale will focus on facies sequences and their lateral variation within the different sub-environments of the contourite depositional system. In addition, we will include carbonate microfacies at the microscopic level for a more accurate differentiation between contourites, turbidites and pelagites, which all contribute, to various degrees, to the accumulation of contourite depositional systems. In particular, we will examine (i) the variability of archetypical bi-gradational contourite sequences and their internal subdivision (bedding, layering, and lamination), and (ii) the type and preservation of traction structures, and (iii) the temporality and impact of bioturbation. The resulting microfacies and bed-scale diagnostic criteria are expected to be applicable to slope deposits worldwide.The results obtained from the large-scale and the small-scale perspective will increase our understanding of the variations and controls within the interconnected sub-environments of the contourite depositional system and will be used to establish a regional facies model. The model will include a compilation of stratification types for all documented contourite deposits and bottom-current reworked turbidite deposits, in order to spatially relate the bed-scale sediment characteristics and microfacies with the drift-scale architecture.

沿坡和下坡海洋沉积流过程的相互作用，导致互层等深岩、浊积岩和相关深水相的堆积，在许多现代大陆边缘已有详细记录。然而，尽管进行了数十年的研究，但人们对这种相互作用的性质，特别是不同相类型之间的区别仍然知之甚少。事实上，关于等深岩，特别是较粗（砂质）等深岩的识别标准，以及与浊积岩的区别，仍然存在很多争议。该项目旨在调查塞浦路斯始新世-中新世大陆坡序列的钙质等深岩和相关的深海相。由于其出色且易于获取的暴露，以及沿坡底流沉积的明确证据，Circum Troodos 沉积记录是陆地上暴露的古代等高线岩的原型实例。第一步，我们评估漂移类型和 3D 几何形状，并建立塞浦路斯碳酸盐等深沉积系统的区域相模型。这种大规模几何评估将基于陆上数字地形和露头模型以及海上地震数据。第二步，我们批判性地评估和改进碳酸盐等深岩和底流改造碳酸盐浊积岩的现有相模型。这些地层规模的研究将重点关注等深岩沉积系统不同亚环境中的相序列及其横向变化。此外，我们还将在微观水平上纳入碳酸盐微相，以便更准确地区分等深岩、浊积岩和远海岩，这些岩类都在不同程度上有助于等深岩沉积系统的堆积。特别是，我们将研究（i）原型二级等高线序列的可变性及其内部细分（层理、分层和层理），以及（ii）牵引结构的类型和保存，以及（iii）生物扰动的时间性和影响。由此产生的微相和层尺度诊断标准预计适用于全球斜坡沉积。从大尺度和小尺度角度获得的结果将增加我们对等高线沉积系统相互关联的子环境内的变化和控制的理解，并将用于建立区域相模型。该模型将包括所有记录在案的等深流沉积物和底流改造浊积岩沉积物的分层类型的汇编，以便在空间上将床层沉积物特征和微相与漂移规模结构联系起来。