Earth planet, or of any other planet or moon.Cryptocrystalline -D[edit]Dacite - an igneous, volcanic rock with a high iron content. Extrusive rock of same general composition as andesite, but a less calcic feldspar. Syn. Quartz andesite.Daughter product - the isotope produced by radioactive decay.Delta - landform where the mouth of a river flows into an ocean, sea, desert, estuary, lake or another river.Degradation - the lowering of a fluvial surface, such as a stream bed or floodplain, through erosional processes.Dendrites - crystal that develops with a typical multi-branching tree-like form.Deposition - geological process by which material is added to a landform or land mass.Detachment fault - major fault in a mountain belt above which rocks have been intensely folded or faulted.Diagenesis - chemical, physical, or biological change undergone by a sediment after its initial deposition and during and after its lithification, exclusive of surface alteration (weathering) and metamorphism.Diamictite - a comprehensive non-generic term for a non-sorted or poorly sorted non-calcareous terrigenous sedimentary rock that contains a wide range of particle sizes such as rock with sand or larger particles in a muddy matrix.Diapir - a type of intrusion in which a more mobile and ductily-deformable material is forced into brittle overlying rocks. A dome or anticlinal fold of the overlaying rocks which has been ruptured by the squeezing out of the plastic core material.Diatomite - naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder.Diopside - a monoclinic pyroxene, ideally consisting of silicate of calcium and magnesium, but commonly containing a variable content of FeSi2O6 in addition, and then strictly known as ferriferous diopside.Diorite - grey to dark grey intermediate intrusive igneous rock composed principally of plagioclase feldspar (typically andesine), biotite, hornblende, and/or pyroxene.Dike or Dyke - a type of sheet intrusion referring to any geologic body that cuts discordantly across. A form of minor intrusion injected into the crust during its subjection to tension, the dyke being thin with parallel sides, and maintaining a constant direction in some cases for long distances. Some are more resistant to weathering than the surrounding rock and stand up like walls, while others weather faster and form long narrow depressions.Dip slope - geological formation often created by erosion of tilted strata.Disconformity - a surface that represents missing rock strata but beds above and below that surface are parallel to one another.Divergent plate boundary - boundary separating two plates moving away from each other.Dolomite - name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg(CO3)2 found in crystals.Dolerite - basic igneous rock of medium grain size, occurring as minor intrusions or in the central parts of thick lava flows. a) A dark-colored, basic, igneous rock, composed essentially of pyroxene and a triclinic feldspar with magnetic iron. Considered by some authors to be equivalent to a coarse-grained basalt. b) A dark, crystalline, igneous rock, chiefly pyroxene with labradorite. c) Coarse-grained basalt. d) Diabase. e) Any dark, igneous rock composed chiefly of silicates of iron and magnesium with some feldspar.Drill core - drill specifically designed