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The average density of basalt is 2.9 g/cm 3, compared, for example, to granite’s typical density of 2.7 g/cm 3. [16] The viscosity of basaltic magma is relatively low—around 10 4 to 10 5 cP—similar to the viscosity of ketchup, but that is still several orders of magnitude higher than the viscosity of water, which is about 1 cP). [17]
The Franciscan Complex or Franciscan Assemblage is a geologic term for a late Mesozoic terrane of heterogeneous rocks found throughout the California Coast Ranges, and particularly on the San Francisco Peninsula.
The melting temperature of dry granite at ambient pressure is 1215–1260 °C (2219–2300 °F); [13] it is strongly reduced in the presence of water, down to 650 °C at a few hundred megapascals of pressure. [14] Granite has poor primary permeability overall, but strong secondary permeability through cracks and fractures if they are present.
Amount and type of matrix present; Composition of gravel-size clasts they contain; Size range of gravel-size clasts present; The classification method depends on the type and detail of research being conducted. [1] [2] [5] A sedimentary rock composed largely of gravel is first named according to the roundness of the gravel.
Orthoclase phenocrysts within a finer-grained matrix of a granite porphyry. The matrix or groundmass of a rock is the finer-grained mass of material in which larger grains, crystals, or clasts are embedded. The matrix of an igneous rock consists of finer-grained, often microscopic, crystals in which larger crystals, called phenocrysts, are ...
The tholeiitic magma series (/ ˌ θ oʊ l eɪ ˈ ɪ t ɪ k /) is one of two main magma series in subalkaline igneous rocks, the other being the calc-alkaline series. A magma series is a chemically distinct range of magma compositions that describes the evolution of a mafic magma into a more evolved, silica rich end member.
A non-standard but widely used abbreviation for one million (1,000,000) years, using the metric prefix M (for "Mega") to indicate a quantity of one million. When not otherwise qualified, it usually indicates 1,000,000 years Before Present (or 1,000,000 years ago). mafic A silicate mineral or rock that is rich in magnesium and iron. A mnemonic ...
Chlorite is one of the most common minerals produced by propylitic alteration by hydrothermal systems, where it occurs in the "green rock" environment with epidote, actinolite, albite, hematite, and calcite. [15] Chlorite pseudomorph after garnet from Michigan (size: 3.5 × 3.1 × 2.7 cm)