recognize some major rock-forming minerals such as quartz, feldspar, calcite, and mica.
Rocks can be identified on the basis of mineral content and texture.
The processes by which rocks are formed define the three major groups of rocks.
The rock cycle is the process by which all rocks are formed and how basic Earth materials are recycled through time.
Igneous rock forms from molten rock that cools and hardens either below or on Earth’s surface. Extrusive igneous rocks have small or no crystals, resulting in fine-grained or glassy textures and include pumice, obsidian, and basalt. Intrusive igneous rocks have larger crystals and a coarser texture and include granite.
Sedimentary rocks may be formed either by rock fragments or organic matter being bound together or by chemical precipitation. Clastic sedimentary rocks are made up of fragments of other rocks and include sandstone, conglomerate, and shale. Non-clastic sedimentary rocks include limestone and rock salt.
Metamorphic rocks form when any rock is changed by the effects of heat, pressure, or chemical action. Foliated metamorphic rocks have bands of different minerals and include slate, schist, and gneiss. Unfoliated metamorphic rocks have little or no banding and are relatively homogenous throughout and include marble and quartzite.
comprehend and identify various igneous rock textural features and mineral components with a hand sample or by description, and analyze the significance of these features in terms of mode of origin and history.
analyze and identify various sedimentary rocks in terms of mode of origin and history, using sedimentary features (grain size, texture, and composition).
analyze the major groups of metamorphic rocks for mineral composition and textural features and determine the potential parent rock and in terms of the rock cycle.
analyze a sequence of rocks in terms of types, textures, composition, fossils, structural, and weathering features in order to infer the history of the sequence over time.
integrate the rock cycle with Plate Tectonics Theory and determine how this is reflected in the geology of Virginia’s five physiographic provinces.
classify the following rock types as igneous, metamorphic, or sedimentary: pumice, obsidian, basalt, granite, sandstone, conglomerate, shale, limestone, slate, schist, gneiss, marble, and quartzite.
differentiate between clastic and non-clastic sedimentary rocks.
compare and contrast distinguishing characteristics of the crystal structure and textures of extrusive and intrusive igneous rocks.
describe the structure of foliated and unfoliated metamorphic rocks.
In Virginia, major rock and mineral resources include coal for energy, gravel and crushed stone for road construction, silica for electronics, zirconium and titanium for advanced metallurgy, and limestone for making concrete.
analyze the formation of fossil fuels in terms of the rock cycle and Plate Tectonics Theory, and relate the formation of fossil fuels to ancient biologic and atmospheric conditions and changes and locations within Virginia.
analyze the geologic history of Virginia in terms of the structures, rock types, and topography represented in the five physiographic provinces
integrate and interpret the rock cycle, plate tectonics, and Virginia’s geology in an interacting diagram.
traces and remains of ancient, often extinct, life are preserved by various means in many sedimentary rocks
rocks and fossils from many different geologic periods and epochs are found in Virginia.
The history of Earth and the ages of rocks can be investigated and understood by studying rocks and fossils