Geochronology data

According to geochronological data obtained by Rb-Sr, U-Pb, °Ar/ Ar methods the following sequence is revealed trachyandesite basalts,... 

The importance of defining settings for Late Cretaceous volcanic activity in this region is emphasised by new geochronological data that show the two kimberlites with the highest diamond estimates to date, K14 and K252, are included in a 14-point Rb-Sr phlogopite isochron age of 81.5 0.8 Ma... 

In addition to geological modelling, geochronological data has significant implication for diamond exploration. A northern Alberta diamond window occurs... 

Abstract strong commodity prices in the last few years have led to a remarkable renaissance of uranium exploration in Labrador, focused in a complex and geologically diverse region known as the Central Mineral Belt (CMB). Potentially economic epigenetic U deposits are mostly hosted by supracrustal rocks of Paleoproterozoic and Mesoproterozoic age, and are difficult to place in the traditional pantheon of uranium deposit types. Recent exploration work implies that structural controls are important in some examples, but the relationships between mineralization and deformation remain far from clear. Geochronological data imply at least three periods of uranium mineralization between 1900 and 1650 Ma. It seems likely that the Labrador CMB represents a region in which U (and other lithophile elements) were repeatedly and sequentially concentrated by hydrothermal processes. The current exploration boom lends impetus for systematic research studies that may ultimately lead to refined genetic models that may be applicable elsewhere. 

Over the last decade considerable effort of the tectonics community has been directed towards the development of thermomechanical models that describe the collisional history and the internal dynamics of orogenic belts and continental plateaus (e.g., Beaumont et al. 2001, 2004 Koons et al. 2002). These models are commonly tested against thermobarometric, thermochronologic, and geochronologic data. However, by definition, these data sets only provide constraints on rates of rock uplift or exhumation the surface response to tectonic... 

Plio-Quatemary magmatism in Italy occurs along a NW-SE trending ex-tensional zone on the Tyrrhenian border of the Italian peninsula, in western Sicily, in the Sicily Channel, on the Tyrrhenian Sea floor and in Sardinia. Geochronological data for the main magmatic centres (Fig. 1.1 Table 1.1) show that there is a general decrease in age from Tuscany and Sardinia towards the south-east, where volcanism is presently active. 

The first two mechanisms leave direct textural evidence for open-system behavior. Samples displaying such evidence yield complex geochronologic data that are difficult to interpret without a detailed understanding of the metamorphic and structural context (e.g., Hames and Cheney, 1997 Arnaud and Eide, 2000 Hoskin and Black, 2000 Di Vincenzo et al., 2001 ... 

Table 1. Geochronological data for Archaean rocks in Zimbabwe... 

Ludwig, K.R. (2000) Processes and challenges in the numerical evaluation of geochronological data, Abstracts and proceedings of the Beyond 2000 New Frontiers. In Woodhead, J.D., Hergt, J.M., Noble, W.P. (Eds) Isotope Geoscience Conference, Lome Australia. Victoria, Australia Eastern Press, pp. 177-199. 

Nelson, D.R. (1994) Compilation of SHIRMP U Pb Zircon Geochronology Data. Perth Geological Survey Western Australia. 

Any detailed geochronological study of slowly cooled rocks will tend to yield discordant results when several different methods of age determination are used. In this section therefore we look closely at the different isotopic systems in an attempt to discover what the different forms of geochronological data mean and what it is that we are actually measuring when we claim to have calculated the geological age of a rock. In this respect one of the most fruitful areas of research has been the application of the con pt of blocking temperatures to geochronological systems. 

Borsi L, Ferrara G, Tonarini S (1988) Geochronological data on Granite Harbor Intrusives from Terra Nova Bay and Priestley Glacier, Victoria Land, Antarctica. Proceedings of Geosciences in Victoria Land, Antarctica, Sept. 1987, Siena, Italy... 

This model successfully integrates structural, stratigraphic, and geochronological data from several areas along the Transantarctic Mountains... and it is consistent with the independent conclusion that Beardmore Group deformation is but one manifestation of a protracted plate-tectonic continuum referred to as the Ross Orogeny. 

Expert group 3 geochronology data Geologists use a wide variety of geochronological tools and methods to estimate the age of rocks and sediments. Using measurements of radioactive isotopes, geologists are able to date all geological materials, from billions of years to the present time. 

Gillot P. Y. and Villari L. K/Ar geochronological data on the Aeolian arc volcanism. A preliminary report. Publ. Istit. int. Vulc. no. 145, 1982. 

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