ROCKS
IGNEOUS ROCKS Rocks that are formed from solidification of molten rock materials.
Tough rocks with no plates visible. 8H Igneous rocks Igneous rocks Tough rocks with no plates visible. The crystals (if you can see them) often interlock and run in different directions. No fossils present – EVER! Rocks do not form in flat beds. Non-porous (will not let water through)
INTRUSIVE IGNEOUS ROCKS Rocks that solidify below the Earth’s surface or underground, cooling slowly to produce coarse-grained rocks.
DIORITE
GABBRO
GRANITE
PEGMATITE
EXTRUSIVE IGNEOUS ROCKS Rocks that solidify above the Earth’s surface, cooling quickly to produce fine-grained rocks.
ANDESITE
BASALT
OBSIDIAN
PUMICE
RHYOLITE
SCORIA
SEDIMENTARYROCKS Rocks that are formed from accumulation of sediments.
Often look like flat plates stuck together. 8H Sedimentary Sedimentary rocks Often look like flat plates stuck together. Grains often visible, these can crumble apart. Fossils can be present. Rocks come from flat beds. Often porous (let water pass through easily).
CLASTIC SEDIMENTARY ROCKS Rocks that are formed from mechanical weathering debris.
BRECCIA
CONGLOMERATE
SAND STONE
SHALE
CHEMICAL SEDIMENTARY ROCKS Rocks that are formed when dissolved materials precipitate from solution.
HALITE / ROCK SALT
Rocks that are formed from accumulation of plant/animal debris. ORGANIC SEDIMENTARY ROCKS Rocks that are formed from accumulation of plant/animal debris.
COAL
METAMORPHIC ROCKS Rocks that are formed through modification by heat and/or pressure deep in the Earth’s surface.
Remains of fossils sometimes present – but not often. 8H Metamorphic rock Metamorphic rocks Often ‘sugary’ with particles that can be arranged in sheets or randomly. Remains of fossils sometimes present – but not often. Beds often have wavy bands. Often less porous than sedimentary rocks – but metamorphic rocks show a wide range of porosity.
FOLIATED METAMORPHIC ROCKS Rocks that have layered or banded appearance due to exposure to heat and direct pressure.
GNEISS
PHYLLITE
SCHIST
Rocks that does not have layered or banded appearance. NON-FOLIATED METAMORPHIC ROCKS Rocks that does not have layered or banded appearance.
MARBLE
AMPHIBOLITE
HORNFELS
QUARTZITE
8H The rock cycle