Watershed Management 地质与地貌

Part 2. The watershedinventoryLecture 6.Geology and landform

Part 2. The watershed inventory Lecture 6. Geology and landform

Part 2.The watershed inventory: lecture 6 geology and landformBedrockBedrock underlies all watershedecosystems. The nature of rock determines thecharacter of overlying soils andinfluences the ultimate movement ofwater draining through those soils.Watershedmanagement--2of13

Part 2. The watershed inventory: lecture 6 geology and landform Watershed management- 6 2 of 13 Bedrock • Bedrock underlies all watershed ecosystems. • The nature of rock determines the character of overlying soils and influences the ultimate movement of water draining through those soils

Part 2.The watershed inventory: lecture 6 geology and landform Bedrocks are formed in one of three ways:by igneous, sedimentary, or metamorphicprocess.Igneous rocks are formed when moltenrock (magma) is pushed up through thecooler regions of the earth's crust fromdeeperzones.Watershedmanaaement--3of13

Part 2. The watershed inventory: lecture 6 geology and landform Watershed management- 6 3 of 13 • Bedrocks are formed in one of three ways: by igneous, sedimentary, or metamorphic process. Igneous rocks are formed when molten rock (magma) is pushed up through the cooler regions of the earth`s crust from deeper zones

Part 2.The watershed inventory: lecture 6 geology and landformSedimentary rocks are composed either offragments of mineral and rock erodedfrom preexisting rocks and thendeposited by natural forces, or ofmaterials precipitated from aqueoussolutions.sandstone: sandy sedimentlimestone: shell and carbonateshales: finest clay sedimentsalt and gypsum: precipitation ofmaterial in solution4of13Watershedmanagement-

Part 2. The watershed inventory: lecture 6 geology and landform Watershed management- 6 4 of 13 Sedimentary rocks are composed either of fragments of mineral and rock eroded from preexisting rocks and then deposited by natural forces, or of materials precipitated from aqueous solutions. sandstone: sandy sediment limestone: shell and carbonate shales: finest clay sediment salt and gypsum: precipitation of material in solution

Part 2.The watershed inventory: lecture 6 geology and landformMetamorphic rocks are created whenigneous or sedimentary rocks aresubjected to further heat and pressure,thus modifying their crystal structureand their physical (but not chemical)properties.Shale → slateLimestone → marbleWatershedmanagement-5of13

Part 2. The watershed inventory: lecture 6 geology and landform Watershed management- 6 5 of 13 Metamorphic rocks are created when igneous or sedimentary rocks are subjected to further heat and pressure, thus modifying their crystal structure and their physical (but not chemical) properties. Shale → slate Limestone → marble