Midterm 1-Rocks and Mineral Flashcards
Weathering Rinds
Rock shows outer weathered zone with successive “layers”of weathering.
Often in combination with chemical weathering.
Resistance to abrasion or scratching and is determined using the MOHs hardness scale
Hardness
Metamorphic rock formed at Low grade metamorphosed basalt-volcanics
From interaction with ocean water or other
fluids → leading to a green colour
Greenstones
Soil Creep
the slow mass wasting process of soil on a slope, under the influence of gravity
Rocky remnants left over from the early formation of our galaxy
Asteroids
Chemical Weathering
Breaks down rock components &
internal structures of minerals
Very coarse grained rocks, formed in the late stage of granitic magma crystallization
Pegmatitic texture
Large grains, surrounded by a finegrained matrix of other minerals similar to the porphyritic texture in igneous rocks
Porphyroblastic textures
Slump
A slump is a form of mass wasting that occurs when a coherent mass of loosely consolidated materials or a rock layer moves a short distance down a slope. Movement is characterized by sliding along a concave-upward or planar surface.
Spheroidal weathering
Rock corners are eroded more rapidly than sides more surface area at corners leading to circular rocks
How do we classify sedimentary rocks?
Shape-degree of roundness form angular,intermediate, to round
Sorting-Very poorly sorted,moderately sorted, and well sorted
Surface extrustions <100km2 and include xenoliths and chill zones
Stock
Fine grained texture, fast cooling(extrusive), microscopic crystals and vesicles from gas bubbles ex.basalt
Aphanitic
Unconsolidated (loose)
Material
Materials not held in place by an adhesive force, at an angle of 35 degrees or greater the face will begin to break apart
Nebular Hypothesis
Solar nebular gas contracted,cooled, and condensed into dust sized particles that aggregated together via collisions into the formation of protoplanets
Fossils
the traces/remains of prehistoric life preserved in rock
Magma intrusions
Volcanic neck,dike,sill,laccolith
Blocky clumpy lava with a liquid underside
Aa lava
Conglomerate
composed mostly of gravel with
rounded fragments but poorly sorted
deposited by strong, turbulent currents such as floods,rivers,steep streams, and glaciers
Fluids effect on metamorphism
Mainly in reference to water and other volitiles it helps to increase the breakdown of ions and facilitate the formation of new crystals coming from either pores in the strata or liquid containing minerals like clay or mica
Composite volcanoes
Larger classical volcano shape made of layers of lava flow and pyroclastic debris. They have large explosive eruptions and form andesite and daltic rocks
non ferromagnesian minerals, composed of Si,K,Na, and Ca
ex.quarts, feldspar,muscovite mica
Light igneous rock
Breccia
conglomerate with angular
grains and have not travelled very far! They can sometimes be confused for pyroclastic rocks
Ripple marks
small waves of sand that show the direction of the wind
symmetric (oscillation ripples), found in areas where the direction of motion changes
asymmetric (current ripples), found in areas where the direction of motion faces on way