2011 - Base level rise and per ascensum model of speleogenesis (PAMS). Interpretation of deep phreatic karsts, vauclusian springs and chimney-shaftses (original) (raw)
Related papers
The Cosquer Cave is a French Palaeolithic painted and engraved cave (27.000-18.500 BP), which is located under the sea, in the Urgonian limestones of Cap Morgiou ("Massif des Calanques", Marseille). The entrance was submerged at the end of the Last Glacial Stage and is presently 37 m under sea level. A synthesis about the Cosquer Cave environmental studies is presented here. Structural studies show that caves planimetry is determined by Cap Morgiou jointing (mainly NW-SE and N-S vertical faults). Through archaeological studies, a speleothem breaking period can be dated between 27.000 and 18.000 BP. Geomorphologic study of the continental shelf at the foot of the Cosquer Cave area shows fossil shorelines at -36 m, -50/55 m, -90 m, -100 m depth. Radiocarbon dating from shells collected in -100m sediments yielded a date of 13.250 BP. Direct scuba diving observations and submarine cliff profiles sketching show several eustatic still stand levels between -36m and the current sea surface indicating a probable tectonic stability during the last 10.000 years.
Evidence of an Early Phreatic and Confined Karst Phase in Minervois, South of France
Advances in Research in Karst Media, 2010
The Minervois karst, South of France, developed in the Eocene carbonate formation, constitutes a regional karst system divided in several subsystems. The Lower Karst Subsystem developing at the base of the series is formed by small to medium size conduits with a circular cross section, organized in mazes and cut off by the canyons. It constitutes the earliest cave development, earlier than the canyons cutting the plateaus. Confined conditions account for the shape and organization of the conduits, which development precedes the down-bending separating Minervois from the Carcassonne basin.
Carbonates and Evaporites, 2013
Karst terrains and their specific landforms, such as sinkholes and caves, have been thoroughly studied from the second half of the nineteenth century. However, karst genesis remains a puzzling issue to this day. The results of the recent studies of ocean floor and the results obtained by drilling deep oil boreholes have raised doubts about the existing explanations of the karst landforms development and encouraged the emergence of new views on this subject matter. According to the new hypothesis, the majority of karst landforms were formed at great depths beneath sea level where dissolution of carbonates increases dramatically. Underwater dissolution first caused the formation of karst depressions and the primary network of karst conduits elongated along the existing fractures. This process was followed by further expansion of the conduits and the formation of spacious caves due to the water regression and the action of turbulent flows. It is considered that the introduction of the new concept would accelerate the development of karstology and improve the principles and methods for solving numerous practical problems such as the abstraction of quality drinking water and the research of oil, gas and bauxite deposits.
Geodinamica Acta, 1999
The cave system is situated north of Lake Thun, in the Helvetic border chain. The overall geology is simple: the slightly dipping (15-25°towards the southeast) strata are interrupted by a NE-SW trending normal fault with a throw of 150 m in the NE and about 500 m in the SW. Since a part of the region is covered by flysch, the caves are the only way to observe the geological setting of the underlying Cretaceous and Eocene series. We show that observations in caves may yield valuable information about the onset of the tectonic movements: in particular, observations in the Bärenkluft region clearly demonstrate that the beginning of prealpine extension had already begun in the Upper Cretaceous, and that this normal fault has been inverted later during Alpine compression. We also illustrate the influence of tectonic stress and strain upon karstification. The Alpine tectonic phases, with alternating compression and extension, contributed to the development of different karstogenetic levels. Tectonic strains opened and possibly closed some fractures, allowing (or preventing) water to flow through parts of the karst massive. The structural setting, defining the overall geometry of the limestone bed, played an important role in the development of the various phases of the system. Most of the conduits appear to belong to old, deep phreatic systems. Tectonics is only one of a number of factors controlling karstification. Together with lithology, it represents the geological control. Geomorphological factors (mainly spring and catchment positions, but also erosion of the flysch cover), as well as bioclimatical factors (quantity and physico-chemical characteristics of water), and hydrodynamics and transport processes can play a significant role on the genesis of karst systems.