Environmental Geology chp. 1-4
Terms
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- What is an atom?
- Atoms are fundamental particles consisting of a nucleus surrounded by a cloud of electrons (-). Neutrons (o) and Protons(+) are in the nucleus.
- What are Isotopes?
- Isotopes are atoms of a particular element that have slightly different atomic weights (protons)neutrons).
- What is an element?
- An element consists of atoms and cannot be further broken down by chemical reactions into a simpler composition.
- What are native elements? compounds?
- Native elements exist as pure solids in nature. Examples are gold and silver.Compounds occur in nature and consist of two or more elements.
- What do minerals consist of?
- Minerals consist of compounds (except for Native Elements). Minerals are solid, naturally occurring, mostly inorganic, and have definite chem. comp.
- What are silicates?
- Silicates are the most volumetrically important family of minerals in the Earth's crust.
- What do silicates consist of?
- Silicates consist of silica oxide (SiO2) combined with other elements. Silicates can be placed into two groups, Felsic and Mafic.
- Describe felsic minerals.
- Relatively rich in silica plus one or more of the following: aluminum, sodium, potassium. Light in color and low densities.
- Examples of felsic minerals.
- Quartz, potassium feldspar (K-feldspar), sodium-feldspar, and muscovite (white mica).
- Describe mafic minerals.
- Relatively low in silica but enriched in iron and magnesium compared to felsic minerals. Dark colored and denser than felsic.
- Examples of mafic minerals.
- bitotite (black mica), hornblende, pyroxene, and olivine.
- Three major types of rocks.
- Igneous, metamorphic, and sedimentary.
- How are igneous rocks formed?
- formed by the cooling and solidification (crystallization) of minerals in Magma (a molten mix of minerals).
- How is magma formed?
- Magma forms by melting rocks and minerals beneath the crust and deep within the crust.
- Intrusive
- Consist of crystals readily visible to the unaided eye. Form intrusions such as batholiths, dikes, and sills.