Terrestrial Ages of Meteorites
نویسنده
چکیده
The terrestrial age, or the terrestrial residence time of a meteorite, together with its exposure history provides us with useful insight into the history of the meteorite. It is easy to observe that stony meteorites can weather quickly in humid environments. However, we find that large numbers of meteorites found in semi-arid and arid environments can survive for much longer times. Meteorites in desert environments can survive for at least 50,000 yr, and there are some meteorites over 250,000 yr old from these locations. The cold and dry conditions of polar regions such as Antarctica are also good for the storage of meteorites. A considerable number of meteorites survive there for hundreds of thousands of years. Some meteorites have been found in Antarctica with ages of up to 2 m.y. In this paper, we discuss the terrestrial residence times or terrestrial ages of these meteorites. We will show the wide range of terrestrial ages from different environments.
منابع مشابه
Terrestrial Ages of Antarctic Meteorites Based on the Thermoluminescence Levels Induced in the Fusion Crust
The fusion crust of eight Antarctic meteorite nds show natural thermoluminescence (TL) levels about 100 times higher than the levels in the fusion crust of freshly fallen meteorites, Dhajala, Jilin and Bansur. If it is assumed that this TL is due to cosmic ray received on the surface of Antarctica, the terrestrial residence times of the meteorites is calculated to lie between 10 10 years. Stric...
متن کاملOxygen Isotope Ratios in the Crust of Iron Meteorites
The separation factor, aM-0= ( 1 8 0 / 1 6 0 ) magnetite/' ( 1 8 0 / 1 6 0 ) atmospheric oxygen, between the magnetite crust of iron meteorites and atmospheric oxygen has been determined to be 0.9946 ± 0.0005. It is concluded that this fractionation of the oxygen isotopes is the consequence of an equilibrium isotope effect at high temperatures. It can be assumed that this is also valid for cosm...
متن کاملCold Desert Alteration of Martian Meteorites: Mixed News from Noble Gases, Trace Elements and Oxygen Isotopes
Introduction: Currently, about 30% of the known Martian meteorites have been found in Antarctica, with some rare samples such as the orthopyroxenite AHL84001 amongst them [1]. We have previously shown [2, 3] that terrestrial weathering in hot and cold deserts can cause elemental fractionation of air incorporated into those meteorites, which complicates the quantification of the noble gas compon...
متن کاملWorkshop on Meteorites from Cold and Hot Deserts
s ............................................................................................................................................... 15 The Fate of Meteoritic Carbon in Hot and Cold Deserts R. D. Ash and C. T. Pillinger ....................................................................................................... 15 Terrestrial Age Clustering of Meteorite Finds from Sites ...
متن کامل