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A method for determining the age in yearsof organic matter by calculating the amount of radioactive carbon stillremaining, as compared to the stable isotope, 12C.
A method used for the dating of potassium-bearingrocks by using the ratio of radioactive 40K to its daughter, 40Ar.
As applied to glacier ice, the process bywhich ice below the snow line is wasted by evaporation and melting.
Geologic time expressed in years beforethe present.
Iron, aluminum, magnesium, manganese,and titanium. Ores of the abundant metals only need to be 3 – 5 timesas metal-rich as average rock.
Large area of extremely flat ocean floorlying near a continent and generally over 4 km in depth.
The rate at which velocity changes, eitherby increasing or decreasing.
The process by which the terrestrial planetsgrew, increasing their mass by gradually accumulating smaller bodies,called planetesimals.
Water contamination by sulfuricacid produced by seepage through sulfur-bearing spoil and tailings fromcoal and metal mining
The acidity in rain due to gases from internalcombustion engines and coal- and oil-burning power plants.
An earthquake that follows and has its epicenternear a larger earthquake.
A siliceous rock with alternating bands of chalcedonyand variously colored chert.
Land counterpart of a delta . An assemblageof sediments marking place where a stream moves from a steep gradientto a flatter gradient and suddenly loses transporting power. Typicalof arid and semiarid climates but not confined to them.
The process of radioactive decay in whichthe nucleus of an atom emits an alpha particle. The new atom’s atomicnumber is lower by two and its atomic mass number is reduced by four.