The Messinian salinity crisis in Cyprus: a further step towards a new stratigraphic framework for Eastern Mediterranean
The Messinian salinity crisis in Cyprus: a further step towards a new stratigraphic framework for Eastern Mediterranean
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塞浦路斯的墨西拿盐度危机：迈向东地中海新地层框架的又一步
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发表时间：
2016
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通讯作者：
E. Turco
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作者：
V. Manzi;S. Lugli;M. Roveri;F. Pierre;R. Gennari;F. Lozar;M. Natalicchio;B. Schreiber;M. Taviani;E. Turco
建议修订塞浦路斯的梅西尼期演替地层框架，表明最近为西地中海建立的梅西尼期盐度危机的三阶段模式也适用于地中海东部，至少适用于其边缘盆地。这一分析是基于对波莱米盆地、皮苏里盆地、马罗尼/PSematismenos盆地和美索利亚盆地中暴露的梅西期蒸发岩和相关矿床的多学科研究。在这里，我们第一次记录到，该单元的底部通常指的是塞浦路斯的“低蒸发岩”，实际上并不对应于梅西尼亚盐度危机的开始。该单元的基面相当于区域尺度的不整合，局部与角度不整合有关，并与梅西尼亚盐度危机第一阶段沉积的原生蒸发岩的侵蚀和再沉积有关。这一证据表明，塞浦路斯南部盆地的“低蒸发岩”实际上属于梅西尼亚盐度危机的第二阶段；因此，它们可归属于5.6~5.5 Ma之间沉积的重沉积下石膏单元，并可能与美索利亚盆地北部沉积的岩盐有关。塞浦路斯盆地没有保存梅西尼亚盐度危机第一阶段的原生原地蒸发岩。相反，在梅西尼亚盐度危机第三阶段沉积的浅水原生蒸发岩保存完好；这些沉积可被视为相当于西西里岛的上石膏。我们的研究表明，梅西尼亚地层学显示出西地中海边缘盆地和东地中海边缘盆地之间的许多相似之处，这意味着梅西尼亚盐度危机的共同和可能的同时代发展。这一点也反映在中、深水盆地中，推测地中海深部盆地的下蒸发岩地震单元可能主要由碎屑蒸发岩组成，其底部可能对应于梅西期的侵蚀面。
A revised stratigraphic framework for the Messinian succession of Cyprus is proposed demonstrating that the three‐stage model for the Messinian salinity crisis recently established for the Western Mediterranean also applies to the Eastern Mediterranean, at least for its marginal basins. This analysis is based on a multidisciplinary study of the Messinian evaporites and associated deposits exposed in the Polemi, Pissouri, Maroni/Psematismenos and Mesaoria basins. Here, we document for the first time that the base of the unit usually referred to the ‘Lower Evaporites’ in Cyprus does not actually correspond to the onset of the Messinian salinity crisis. The basal surface of this unit rather corresponds to a regional‐scale unconformity, locally associated with an angular discordance, and is related to the erosion and resedimentation of primary evaporites deposited during the first stage of the Messinian salinity crisis. This evidence suggests that the ‘Lower Evaporites’ of the southern basins of Cyprus actually belong to the second stage of the Messinian salinity crisis; they can be thus ascribed to the Resedimented Lower Gypsum unit that was deposited between 5.6 and 5.5 Ma and is possibly coeval to the halite deposited in the northern Mesaoria basin. Primary, in situ evaporites of the first stage of the Messinian salinity crisis were not preserved in Cyprus basins. Conversely, shallow‐water primary evaporites deposited during the third stage of the Messinian salinity crisis are well preserved; these deposits can be regarded as the equivalent of the Upper Gypsum of Sicily. Our study documents that the Messinian stratigraphy shows many similarities between the Western and Eastern Mediterranean marginal basins, implying a common and likely coeval development of the Messinian salinity crisis. This could be reflected also in intermediate and deep‐water basins; we infer that the Lower Evaporites seismic unit in the deep Eastern Mediterranean basins could well be mainly composed of clastic evaporites and that its base could correspond to the Messinian erosional surface.