A crystal that grew while temperatures were changing or while the composition of the parent solution was changing. Crystals of these minerals can have a range of compositions, with a certain chemistry in the center reflecting the early growth conditions and the outer chemistry reflecting the later growth conditions. Minerals such as olivine or plagioclase which have a solid solution series frequently form such crystals.
Structure formed by the lateral growth and merger of fans made by neighboring streams.
Regular patterns of ripples and cusps in sediment on the beach or the sea floor, formed by currents and waves.
A measure of earthquake strength based upon the amount of ground motion experienced and corrected for the distance between the observation point and the epicenter. There are several magnitude scales in use.
Iron ore composed of disk-shaped oauolites that have been partially flattened parallel to the bedding plane.
A theoretical representation of the marine environment which relates physical, chemical, geological, biological, and other oceano-graphic properties.
In the southwestern United States, a basin or valley having no outlet.
Abbreviation used in this book for plain polarised light
A cloud of bubbles at the sea surface caused by a breaking wave.