Question

Provide written answers and diagrams for two of the questions below. 1. Sketch and explain the sedimentary cycle. What processes are at work in each stage? 2: On the back side of this page. draw pictures of the following sedimentary features and explain how they form: ripple marks cross beds mudcracks graded beds 3. Define clastic and chemical sedimentary rocks and tell how the two groups differ. How do the two types of weathering (physical and chemical) relate to how both groups originate? Give two examples of both groups. 4. List at least four of the main causes of controls on) metamorphism and explain how they form metamorphic rocks. 5. List and describe the three main types of metamorphic foliations. Explain how they form. What aspect the rock (on the scale of the mineral crystals) determines if the rocks are foliated? 6. Draw a cross section of the Madison Canyon rockslide and list the 4 main geologic factors that led to the slide. 7. Explain how stream velocity is affected by the following channel characteristics? gradient roughness size cross sectional shape discharge

Answer 1

These are the rocks formed by 3. Clastic sedimentary rocks - various mechanical process like erosion, transportation, deposition basin, o of Sediments in a low lying area called under excessive bressure is consolidate a The deposited sediment . lithification and cementation examples are Sandston, Shale, conglomerate, Breccia. Chemical Sedimentary socks :- These rocks are generally formed on: Chemical ºbrecipitation of dissolved matter derived from provenonce by the process of chemical weathering enamples are ! Limestone, dolostone, rock salt, Gypsum etc. • Physical weathering :- It is also called as mechanical weathering It includes the processes that break down the structure of pse -enisting rock with changing its components The broken material is called sediment or clast. that form clastic sedimentary rock. • Chemical Weathering this process does not damage or break the ! rock physically but sather it is a reaction between the chemical composition of pse -enisting rocks and outside Chemicals like water and air mainly onggen - Clastic rocks - Sandstone, Shale. Chemical sedimentary rocks ! Limestone, dolostone ..

Four main causes of metomosphism are :- (a) Temperature enperienced by rock. (b) Amount and type of pressure. O Amount and type of chemically active fluid present. Id Amount of time arailable for metamosphism · (a) Temperature: Increase in temperature accelerate the process of reaction, it also increase the volume of rock. Remove various volatiles and moisture present in rock. temperature increases due to moinly . in Geothermal gradient '24-30°C/ km (23 Rodioactive' decay in earth's crust. c6 Pressure :: Pressure can be ading in two ways. ( Directed pressure. • mainly act in upper part of earth crust and cause. chonge of shape orientation of mineral Develop fracture, foliation etc. (2) Lithostatic pressure also called as confining pressure • It mainly od in deep rooted Condition - Yond cause. reduction in volume, increase in density of rock Formation of gronulase textust take place. It semoves volatile content forming anhydacris mineral. (o Chemically active fluids • It include water vapour, carbon dioxide, HCI, CHA and other volatiles which acts as catalyst in the reaction taking blace. When rock i subjected to high temperature or Session Sources of these fluids are in connate water (9) Meteoric water' (3) Juvenile or magmatic water (os Time in The metamorphic process is rearrangement and secrystallization of mineral which carried out in due course of time. me.