Chapter 5 Geology

clay minerals

-Acid waters react with feldspar and alter them to ?

WEATHERING

-Chemical or physical process that breaks down rocks into smaller pieces

A-horizon

-Dark layer, rich in organic matter (humus) and high biologic activity

C-horizon

-Partially weathered bedrock

MECHANICAL WEATHERING

-Physical processes - such as abrasion, growing plant roots, expanding ice, or burrowing animals - that naturally break rocks into smaller pieces

EROSION

-Physical removal or picking up of rock fragments would be regarded as -Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)

carbon dioxide

-The most important natural source for the formation of acid for rock weathering at the earth's surface is dissolved ?

DIFFERENTIAL WEATHERING

-The process by which softer, less weather resistant rocks wear away and leave harder, more weather resistant rocks behind.

CHEMICAL WEATHERING

-The process in which rock is broken down by changes in its chemical makeup

O-horizon

-Uppermost layer consisting entirely of organic matter

B-horizon

-Zone of accumulation of clays, Fe oxides and calcite leached from above

E-horizon

-Zone of leaching, fine-grained components removed by percolating water

SOIL

-a mixture of weathered rock, rock fragments, decayed organic matter, water, and air -45% minerals, 5% organic matter, and 50% pore space for air and water

SOLUTION WEATHERING

-when carbon dioxide dissolves into rainwater as it falls through the air, creating acid rain. Acid rain reacts with the soluble minerals and carries them away -chemical weathering dissolves rock; calcite dissolves easily (limestone, metamorphic rock marble)

Sandstone and shale

DO NOT weather at the same rate.

Bowen's reaction series

Shows the order of mineral crystallization and composition of rocks

Quartzite

Which metamorphic rock has been subjected to contact metamorphism (not foliated)? -quartz does not usually weather chemically