Le karst des plateaux jurassiques de la moyenne valee de l'Ardeche; datation par paleomagnetisme des phases d'evolution plio-quaternaires (aven de la Combe Rajeau)

2001 ◽  
Vol 172 (1) ◽  
pp. 121-129 ◽  
Author(s):  
Philippe Audra ◽  
Hubert Camus ◽  
Pierre Rochette
Keyword(s):  
Radiometric Dating ◽  
Base Level ◽  
Cave System ◽  
Knowing That ◽  
Precise Knowledge ◽  
Recent Part ◽  
Piezometric Surface ◽  
Underground River ◽  
Karst Systems ◽  
Level Lowering

Abstract Thanks to its immunity, karst is an excellent recorder of environmental change, which also offers the possibility for dating. Karst records position of old base levels, in particular to which were linked horizontal underground drains located near the piezometric surface. After a base level lowering, a new drain appears at a lower level, the old perched drain being abandoned. If base level lowering is slow, the initial drain is progressively entrenched, forming a canyon. The "Combe Rajeau" cave system corresponds to this last type: a 100 m high underground canyon, continuously entrenched during the Ardeche valley downcutting. The underground river left several terraces during the entrenchment. Knowing that speleothem U/Th radiometric dating method covers only the most recent part of karst systems history, which spans over several million years, paleomagnetism has been applied to date the Combe Rajeau sediments. A more precise knowledge of the evolution phases of this system provides a better understanding of the middle Ardeche valley evolution upon which it depends.

scholarly journals New Chronological Constraints from Hypogean Deposits for Late Pliocene to Recent Morphotectonic History of the Alpi Apuane (NW Tuscany, Italy)

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 65
Author(s):  
Ilaria Isola ◽  
Francesco Mazzarini ◽  
Giancarlo Molli ◽  
Leonardo Piccini ◽  
Elena Zanella ◽  
...  
Keyword(s):  
Radiometric Dating ◽  
Early Pleistocene ◽  
Late Pliocene ◽  
Mountain Ranges ◽  
Fluvial Deposits ◽  
Fine Grained ◽  
Base Level ◽  
Cave System ◽  
Cave Sediments ◽  
History Of

A sedimentary sequence of fluvial deposits preserved in the Corchia Cave (Alpi Apuane) provides new chronological constraints for the evolution of the cave system and the timing and rate of uplift of this sector of the Alpi Apuane since the late Pliocene. Supported by magnetostratigraphic analysis performed on fine-grained fluvial deposits, and by radiometric dating of speleothems, we suggest that the deposition of fluvial sediments occurred between ~1.6–1.2 Ma. This implies that the host volume of rock was already located close to the local base level, adding key information about the recent tectonic evolution of the Alpi Apuane. A few before ~1 Ma, an erosive phase occurred due to the base-level lowering, followed by continuous speleothem deposition since at least 0.97 Ma. From that time, Monte Corchia uplifted at a maximum rate of ~0.5 mm/year, which is consistent with isostatic uplift mainly driven by erosional unloading. The petrographical study of the fluvial deposits highlights the presence of material derived from the erosion of rocks that today are absent in the cave’s catchment area, suggesting a different surface morphology during the Early Pleistocene. This study highlights the potential of cave sediments as archives for reconstructing the uplift history of mountain ranges.

Chasing sand: evolution of the surface and subsurface drainage of the Sinkhole Plain, Central Kentucky Karst, USA

2021 ◽  
Author(s):  
Rachel Bosch ◽  
Dylan Ward
Keyword(s):  
Network Flow ◽  
Stream Network ◽  
Green River ◽  
Clastic Rocks ◽  
Base Level ◽  
The North ◽  
Cave System ◽  
History Of ◽  
Karst Systems ◽  
Profile Reconstruction

<p>This work extends the established geochronology of the Mammoth Cave region, Kentucky, USA, spatially and temporally, to infer evolution of the karst landscape and to consider the shifting drainage basins of the Barren River and the Green River in relation to regional drainage rearrangements. Previous studies have focused on the Mammoth Cave System and used cosmogenic radionuclide dating to link the incision history of the Green River and the Cave as far back as 3.25 Ma. We posit that prior to the wide-spread karstification that produced Mammoth Cave, drainage consisted of a purely fluvial stream network flow on the youngest clastic rocks. When this caprock was breached, carbonate dissolution ensued and the system transitioned to fluviokarst. Relict large trunk passages that originated at that time can be found in features such as Prewitts Knob, Bald Knob, and Huckleberry Knob. We intend to use sediments and speleothems collected from Crystal Onyx Cave in Prewitts Knob to constrain the age of this stage of karst development and to provide an estimate of the long-term erosion rate of the Sinkhole Plain surrounding the knob. These relict trunks were also used for cave stream profile reconstruction in combination with the east-west trending uvalas and sets of steep, deep sinkholes. We interpret that paleodrainage as having been west-flowing into the Barren River which then served as regional base level. Thus, we infer that as the rivers incised, this drainage was pirated to the north and began flowing to the Green River. The system then evolved into a more mature karst, large conduits near the surface collapsed, and dissected the landscape into isolated depressions. The collapsed limestone formed red soil and the sandstone produced angular clasts scattered throughout that soil. The retreating Chester Cuesta, marking the boundary between the Sinkhole Plain and the sandstone-capped Chester Upland, eroded most rapidly where limestone was exposed to the surface and more slowly where it was sandstone-capped leaving abandoned isolated cave trunk passage segments in remnant knobs. The results of this work have implications for understanding timescales of the evolution of karst systems in unconfined carbonate sequences as well as the interaction of karst areas with the transience in drainage networks.</p>

scholarly journals Cosmogenic burial dating of in cave-deposited alluvium: unravelling long-term incision rates and complex speleogenesis in multi-level cave systems

2020 ◽  
Author(s):  
Gilles Rixhon ◽  
Didier L. Bourlès ◽  
Régis Braucher ◽  
Alexandre Peeters ◽  
Alain Demoulin
Keyword(s):  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Fluvial Terrace ◽  
Base Level ◽  
Cave System ◽  
River Incision ◽  
Order Of Magnitude ◽  
History Of ◽  
Multi Level

<p>Multi-level cave systems record the history of regional river incision in abandoned alluvium-filled phreatic passages which, mimicking fluvial terrace sequences, represent former phases of fluvial base-level stability. In this respect, cosmogenic burial dating of in cave-deposited alluvium (usually via the nuclide pair <sup>26</sup>Al/<sup>10</sup>Be) represents a suitable method to quantify the pace of long-term river incision. Here, we present a dataset of fifteen <sup>26</sup>Al/<sup>10</sup>Be burial ages measured in fluvial pebbles washed into a multi-level cave system developed in Devonian limestone of the uplifted Ardenne massif (eastern Belgium). The large and well-documented Chawresse system is located along the lower Ourthe valley (i.e. the main Ardennian tributary of the Meuse river) and spans altogether an elevation difference exceeding 120 m.</p><p>The depleted <sup>26</sup>Al/<sup>10</sup>Be ratios measured in four individual caves show two main outcomes. Firstly, computed burial ages ranging from ~0.2 to 3.3 Ma allows highlighting an acceleration by almost one order of magnitude of the incision rates during the first half of the Middle Pleistocene (from ~25 to ~160 m/Ma). Secondly, according to the relative elevation above the present-day floodplain of the sampled material in the Manants cave (<35 m), the four internally-consistent Early Pleistocene burial ages highlight an “anomalous” old speleogenesis in the framework of a gradual base-level lowering. They instead point to intra-karsting reworking of the sampled material in the topographically complex Manants cave. This in turn suggests an independent, long-lasting speleogenetic evolution of this specific cave, which differs from the <em>per descensum</em> model of speleogenesis generally acknowledged for the regional multi-level cave systems and their abandoned phreatic galleries. In addition to its classical use for inferring long-term incision rates, cosmogenic burial dating can thus contribute to better understand specific and complex speleogenetic evolution.</p>

scholarly journals Cosmogenic nuclide dating of cave sediments in the Eastern Alps and implications for erosion rates

2020 ◽  
Vol 49 (2) ◽  
pp. 107-118
Author(s):  
Philipp Häuselmann ◽  
◽  
Lukas Plan ◽  
Peter Pointner ◽  
Markus Fiebig ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Eastern Alps ◽  
Western Alps ◽  
Valley Bottom ◽  
Cosmogenic Nuclide ◽  
Base Level ◽  
Multi Level ◽  
Slow Evolution ◽  
Karst Systems ◽  
Cosmogenic Nuclide Dating

Karstic caves are created by water eroding and corroding rocks that can be dissolved. Since both the spring areas of caves (normally at the valley bottom) as well as the recharge is controlled by superficial processes, the morphology of the cave bears strong links to these influences. Lowering of local base levels promotes the development of horizontal phreatic cave passages at progressively lower elevations, resulting in the formation of multi-level karst systems. Upon the next lowering of base level, these upper systems become fossilized, and sediment trapped within them may remain preserved for millions of years. Dating these sediments gives clues regarding the time when the passages were last active, and thus may yield age information for old valley floors. The present paper presents cosmogenic nuclide datings of twelve samples from eight caves in the central part of the Northern Calcareous Alps of Austria. Besides three samples that gave no results, most of the obtained ages are at the Mio-Pliocene boundary or within the Pliocene, as was expected before sampling. No multi-level caves could be sampled at different elevations, thus, the obtained valley deepening rates are averages between the age of sediment deposition and the present-day valley floor. However, the valley deepening rates of 0.12 to 0.21 km/Ma are in accordance to previous findings and corroborate a comparatively slow evolution of base level lowering in the Eastern Alps compared to the fast (Late Quaternary) evolution in the Central and Western Alps.

scholarly journals Analysis of Cavities Characteristics in the Semar - Kiskendo Caves System, Jonggrangan Karst Area, Kulon Progo, Indonesia

2019 ◽  
Vol 125 ◽  
pp. 01016
Author(s):  
Romza Fauzan Agniy ◽  
Risma Sari Septianingrum ◽  
Ariel Seto Adinugraha ◽  
Qodri Alghozali ◽  
Bagas Aditya ◽  
...  
Keyword(s):  
Water Source ◽  
Average Diameter ◽  
Tracer Test ◽  
Karst Area ◽  
Survey Method ◽  
Cave System ◽  
Underground River

The Kiskendo Cave System is a system that has many benefits, including as a tourist site and water source. One of the systems in the upstream of Kiskendo Cave is the Semar-Kiskendo Caves system. This system is estimated to greatly affect the condition of the Kiskendo cave system because it is connected to the allogenic river which contributes to recharge from outside Jonggrangan Karst Area. The purpose of this research was 1) to find out the characteristics of the Semar Cave cavities and 2) to analyze the connectivity and characteristics of cavities in the Semar - Kiskendo Caves system. This research employed a survey method by mapping the cave to answer the first problem and conducting a tracer test of underground river stream to answer the second problem. The results showed that the Semar Cave cavity that could be mapped was 158.2 meters long, the total volume of the cave was 1,220.6 m3, and the average diameter of the cave cavity was 2.8 meters. The results of second study using the tracer test showed the connection between Semar Cave and the underground river in Kiskendo Cave, and the cavities had a characteristic of a single conduit which was sufficiently developed.

Stream channel convexity induced by continuous base level lowering, the Dead Sea, Israel

Geomorphology ◽  
2007 ◽  
Vol 92 (1-2) ◽  
pp. 60-75 ◽  
Author(s):  
Dan Bowman ◽  
Yonit Shachnovich-Firtel ◽  
Shlomo Devora
Keyword(s):  
Dead Sea ◽  
Stream Channel ◽  
Base Level ◽  
The Dead ◽  
Level Lowering

High-resolution Stratigraphy of Holocene Lagoon Terraces of Southern Brazil

2015 ◽  
Vol 83 (1) ◽  
pp. 52-65 ◽  
Author(s):  
Natália B. dos Santos ◽  
Ernesto L.C. Lavina ◽  
Paulo S.G. Paim
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Radiometric Dating ◽  
Sea Level Changes ◽  
Relative Sea Level ◽  
Base Level ◽  
Depositional Processes ◽  
Close Relationship ◽  
Northern Portion ◽  
Depositional Architecture

AbstractThe northern portion of the coastal plain of the Rio Grande do Sul State (southernmost Brazil) comprises an outer sandy barrier that protects a complex lagoon system formed during the Holocene. The terraces of three different lagoons (Gentil, Malvas and Pinguela) formed along their margins record the depositional processes and the relative base level changes over the past 5000 yr. Therefore, our main objective was to characterize and quantify base level fluctuations from the study of these terraces, to correlate them to sea-level changes and to describe the depositional architecture related to the distinct sea-level stages (high-resolution sequence stratigraphy). Satellite images, topographic and GPR profiles, auger holes and radiometric dating were used. The main results indicate a close relationship between relative base level and relative sea-level changes, a stillstand period just after the last transgressive maximum (4840–4650 cal yr BP) and a subsequent overall relative sea-level fall of about 3 m. Both a normal (highstand systems tract) and a forced regression (falling-stage systems tract) controlled the geological record preserved in the terraces. The highstand (older terrace) is characterized by agradational bedding, whereas the falling stage comprises three progradational sets (terraces) bounded by erosive surfaces related to smaller-scale sea-level drops.

scholarly journals Discovery of a new population of the federally endangered Alabama Cave Shrimp, Palaemonias alabamae Smalley, 1961, in northern Alabama

2019 ◽  
Vol 32 ◽  
pp. 43-59
Author(s):  
Matthew L. Niemiller ◽  
Thomas Inebnit ◽  
Amata Hinkle ◽  
Bradley D. Jones ◽  
Mark Jones ◽  
...  
Keyword(s):  
Metropolitan Area ◽  
River Valley ◽  
Karst Region ◽  
Main Stream ◽  
Genetic Analyses ◽  
Jackson County ◽  
Madison County ◽  
Base Level ◽  
Cave System

The Alabama Cave Shrimp Palaemonias alabamae Smalley, 1961 is a federally endangered cave shrimp endemic to just four cave systems within and near the greater Huntsville metropolitan area in Madison County, Alabama USA. It is one of two described atyid cave shrimp in the Interior Low Plateau karst region. Here we report the discovery of a new population of P. alabamae from the Fern Cave system in western Jackson County, Alabama. We observed four cave shrimp in August 2018 in an isolated pool in the base-level stream passage of the longest cave system in Alabama. Two cave shrimp were observed during a subsequent survey in July 2019: one in the same isolated pool and a second shrimp in a pool in the main stream passage. Morphological and genetic analyses confirm that this population is closely allied with other populations in Madison County. This new population expands the known distribution of the species into a new county and watershed (Lower Paint Rock River). The potential exists to discover additional populations in Paint Rock River valley and other nearby regions.

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