What types of rocks are good for radiometric dating
barrier island - A long, narrow island parallel to the shore, composed of sand and built by wave action.
basalt - A fine-grained, dark, mafic igneous rock (~50% Si O) composed largely of plagioclase feldspar and pyroxene; rough volcanic equivalent of gabbro.
anorthosite - An igneous rock predominantly composed of plagioclase feldspar (90–100%), and a minimal mafic component (0–10%).
Anorthosites constitute the light-colored areas of the Moon's surface.
bar-finger sand - An elongated lens of sand deposited during the growth of a distributary in a delta.
The bar at the distributary mouth is the growing segment of the bar finger.
aeolian process - A geological modification, such as sand dunes or erosion, caused by wind activity. algal mat - A layered communal growth of algae observed in fossils and in present day tidal zones associated with carbonate sedimentation.
asphalt - A dark bituminous substance found in natural beds. asthenosphere - The highly viscous, mechanically weak region of the upper mantle of the Earth that lies below the lithosphere at depths between 100 and 200 km below the surface.atoll - A continuous or broken circle of coral reef and low coral islands surrounding a central lagoon.autochthonous - Refers to something formed in its present location. backwash - The return flow of water down a beach after a wave has broken.amber - A fossilized resin from a coniferous tree that sometimes contains entrapped and preserved insects.amphibole - group of generally dark-colored rock-forming inosilicate minerals, composed of double chain Si O), less mafic than basalt, but more mafic than dacite; rough volcanic equivalent of diorite.
bankfull stage - The height of water in a stream that just corresponds to the level of the surrounding floodplain.