Last glacial maximum deglaciation of the Southern Velebit Mt. Naslov Last glacial maximum deglaciation of the Southern Velebit Mt. Croatia : insights from cosmogenic 36Cl dating of Rujanska Kosa. Izvornik Mediterranean Geoscience Reviews X 2 ; Here we present the first cosmogenic 36Cl glacial chronology from the Southern Velebit Mt. The inner Rujanska Kosa ridge yielded an age of A slightly older age was measured from the outer ridge on the left-lateral part of the Rujanska Kosa, which dates back to Whilst the ages between inner and outer ridges overlap within error, we can place an age difference between the two moraines to be between 0 and 6.
Cosmogenic 36Cl dating of the Foothills erratics train, Alberta, Canada
The 36 Cl content of the groundwater is assumed to be completely of atmospheric origin. This is a preview of subscription content, log in to check access. Rent this article via DeepDyve. Allen RJ Climate. Occasional publications 6, Royal Society of South Australia, pp 81—
significant as it was the first time that old groundwater was definitively dated. These 81Kr ages were then used to calibrate the 36Cl dating method (18).
Cosmic-ray exposure dating of preserved, seismically exhumed limestone normal fault scarps has been used to identify the last few major earthquakes on seismogenic faults and recover their ages and displacements through the modelling of the content of in situ [ 36 Cl] cosmonuclide of the scarp rocks. However, previous studies neglected some parameters that contribute to 36 Cl accumulation and the uncertainties on the inferred earthquake parameters were not discussed.
Through a series of synthetic profiles, we examine the effects of each factor on the resulting [ 36 Cl], and quantify the uncertainties related to the variability of those factors. Those most affecting the concentrations are rock composition, site location, shielding resulting from the geometry of the fault scarp and associated colluvium, and scarp denudation. In addition, 36 Cl production mechanisms and rates are still being refined, but the importance of these epistemic uncertainties is difficult to assess.
We then examine how pre-exposure and exposure histories of fault-zone materials are expressed in [ 36 Cl] profiles. We show that the 36 Cl approach allows unambiguous discrimination of sporadic slip versus continuous creep on these faults. By contrast, the modelling cannot discriminate whether a slip event is a single event or is composed of multiple events made of temporally clustered smaller size events.
As a result, the number of earthquakes identified is always a minimum, while the estimated displacements are maximum bounds and the ages the approximate times when a large earthquake or a cluster of smaller earthquakes have occurred.
Dating ultra-deep mine waters with noble gases and 36Cl, Witwatersrand Basin, South Africa
Go back. Overview Organisations People Publications Outcomes. Abstract Funding details. Publications The following are buttons which change the sort order, pressing the active button will toggle the sort order Author Name descending press to sort ascending. Beck J Bayesian earthquake dating and seismic hazard assessment using chlorine measurements BED v1. Cowie P Viscous roots of active seismogenic faults revealed by geologic slip rate variations in Nature Geoscience.
36Cl terrestrial cosmogenic nuclide dating suggests Late Pleistocene to Early Holocene mass movements on the south face of Aconcagua mountain and in the.
Chlorine has two stable isotopes and one cosmogenic isotope. The cosmogenic isotope, 36 Cl, has a long half-life, making it useful in age dating groundwaters up to 1 million years old. There is also limited variation in 37 Cl. Most natural variation in 37 Cl values in hydrologic systems are related to diffusion processes. Origin return to top 36 Cl – Natural Production 36 Cl is produced naturally in the atmosphere and within solid materials at the earth’s surface.
High-energy cosmic ray particles collide with atoms in the earth’s atmosphere producing protons and neutrons. After the emission of other particles to lower the energy state, the final result is either a stable element or a long-lived radioactive isotope. Roughly two thirds of atmospheric 36 Cl is produced by the following spallation reaction:. The other third of the atmospheric 36 Cl is produced by this spallation reaction:.
Lionel E. Jackson, Fred M. Phillips, Kazuharu Shimamura, Edward C.
Cosmogenic 36 Cl exposure dating was carried out on erratics over a km segment of the erratics train. Seven of eight age determinations support.
The code models a 36 Cl profile accumulated in the fault scarp surface through a guessed rupture history, and compares the modeled and measured 36 Cl profiles with statistical tests. Rupture histories are randomly generated in bounded solution space using Monte-Carlo method or optimized using Random Walk algorithm to achieve the best fit of the modeled and measured 36 Cl profiles. The code has a user-friendly interface, a build-in help and an example of input data.
The full description of the methods used to acquire the datasets of the Kalafat and Yavansu fault scarps is published in the main publication . The description includes the sampling in the field, mechanical and chemical preparation and details on sample measurement with accelerator mass-spectrometry. In this publication we would like to present the computation code used to analyze the datasets. The code applies forward modeling and Monte-Carlo algorithms to determine the most probable displacement history: the age of displacement events, the displacement values slips and the uncertainty of ages and slips.
Displacement histories are randomly generated, transformed to 36 Cl concentration profile and compared to measured concentrations with goodness-of-fit tests. The current code is an improved and updated version of the previous FSDT code published in . The program has build-in help files and a user-friendly graphic interface. Output of the program is presented graphically and numerically and can be saved in a variety of file formats.
Permafrost dating by Cosmogenic 36Cl and 10Be and its applications to bio- and Geoscience
Jump to navigation. Science Support Program. Search form Search. Chlorine Chlorine In situ cosmogenic 36 Cl is produced by interaction of cosmic rays with different target elements, mainly calcium, potassium and chlorine 35 Cl. We try to avoid rocks with high chlorine concentrations because of the complex 36 Cl production mechanism from chlorine, and we therefore focus on mineral separates rather than whole silicate rocks.
Workshop on Dating of Old Groundwater (The University of Arizona, Tucson, ). Google Scholar. 8. Wallick, E. I. thesis, Univ. Arizona ().
Deep groundwater samples from the Continental Intercalaire CI aquifer in the Northern Tunisian Sahara have been analyzed for noble gases 3 He, 4 He, Ne and 81 Kr, and for 14 C to better constrain the groundwater residence time of this large transboundary aquifer. Its significant radiogenic 4 He content and background-level 14 C both indicate water older than a few tens of thousands of years. Here, this study exemplifies the utility of 81 Kr not only as an independent and conservative chronometer, but also as a supplemental measurement to better calibrate the parameters required for other age tracers, including cosmogenic 36 Cl and radiogenic 4 He.
Permafrost is one of the most sensitive parts of the lithosphere that reacts to the climate changes. Within its horizons, geological events and climatic oscillations have been reflected in permafrost accumulation and degradation. The presented interdisciplinary project focuses on a key geocryological problem which has not been solved yet, that is, the direct determination of the permafrost age. In order to approach this problem, a method of direct permafrost dating back to 1.
The proposed dating method is based on the determination of the time of 36Cl fixation within ice i.
2 Overview of the 36Cl Dating Approach. The interaction of cosmic rays with rocks exposed at the Earth’s surface produces cosmogenic isotopes.
PhD thesis: Cosmogenic Cl in Ca and K rich minerals: analytical developments, production rate calibrations and cross calibration with He-3 and Ne Pdf. Mechernich, S. Simon, K. Nuclear Inst. Palacios, D. Geomorphology , Alcala-Reygosa, J. Journal of Volcanology and Geothermal Research, accepted. Styllas, M. Quaternary Science Reviews , Quaternary Geochronology, in press.
Vermeesch, P. Proceedings of the Royal Society A Jomelli, V.