Lecture 12 Flashcards
What are the characteristics of the clastic sedimentary rocks?
Composed predominantly of silicate fragments (clasts) such as individual silicate materials (quartz, feldspar), and rock (lithic fragments)
How do clasts form sedimentary rocks?
Undergo weathering and erosion, transport, deposition and lithification.
What happens in the process of weathering and erosion?
Temperature fluctuations from day to night, precipitation, flowing water, and increased chemical activity weather rocks into clasts
What is physical weathering?
Bedrock is broken into smaller fragments, composition of minerals remains unchanged
What is chemical weathering?
Water and dissolved ions react with solid rock to produce materials of different compositions
What is bauxite?
Chemical weathering of granite-primary source of aluminum
What are bioclasts?
Pieces of fossilized organisms-clasts of biogenic origin
What are lithoclasts?
Clasts which have tons of minerals, smaller versions of preexisting rocks that were disintegrated.
What is Eolian transport?
Materials transported by wind (Deserts, volcanic ash)
What is glacier transport?
Materials transported by ice
what is stream and river transport?
Most common and important. Continental water transport.
What is the process of deposition?
Begins when clasts enter the sedimentary basin and ends when it settles
What is the process of lithification?
Conversion of sediment into rock. Happens because sediments are constantly transported and buried-weight of newly added sediment fills spaces.
What are the 2 lithification processes?
Compaction and cementation
What is compaction?
Reduction of volume wit burial
