Sedimentary Geology — DU B.Sc. (Hons.) Geology Previous Year Question Papers

7. (i) State the ilnportance of porosity and permeability in sediments arid how does it change as the sediments form solid rock? Explain with sketches. (ii) Describe the forces that combine to entrain a grain. Draw a picture to explain your answer? (iii) With the help of a labeled diagram, describe the different types of particle movement in a stream and explain. the following : 1. Movement of bedload 2. Transport of suspended load and the conditions undgr which it settles. 8. (i) Discuss the factors con.trolling limestone formation in marine environments, 4 emphasi.zing the role of carbon dioxide removal from seawater? ` (ii) Explain the classification scheme for carbonate rocks, detailing how it distinguishes between allochemical and s components, and discuss its significance in understanding' carbonate rock composition and origin. Name of. the Course : Sedimentary Geology : B.sc. (H.) Geology OrEP- 1.. (i) Explain how weathering, sedimentation, and recycling of sediments contribute to the evolution of the continental crust. (ii) Explain how variations in relief, temperature, and moisture .influence. the type and composition of weathering products generated in the arid and humid climate. 2. (i) Expl'aii the statistical parameters (mean, inedian, mode, standard deviati.on, and skewness) in the-context of sediment granulometry, and discuss t_heir significance in iflterpreting sed.iment characteristics, sorting, transport history, and deposit`ional environ_ments. (ii) Discuss the "flow regime concept" considering Reynolds' and Froud numbers. (c) Walther's law of facies succession. (d)Grain sphericity and roundness and their significance. (e) Role of organis.ms in the precipitation of calcium carbonate. (i) 3. (i) Withthe help of grain-size classification, discuss major categories of terrigenous sediments and their associated sedimentary rock types. (ii) List and briefly describe the methods used to measure grain size in both unconsolidated sedimeits and consolidated (stratified) rocks. (iii) Explain the stages of textural maturity in sandstones and. describe the changes, in grain Characteristics and sorting that occur. during each stage. 4. Write a short note' on any three of the following : (a) Influence of c.1imate, relief, and source rock on the characteristics of primary detrital sediments. (b) Relative stability of common rock-forming minerals (Goldich Stability Series). (ii) Describe how geologists identify the stratigraphic up' direction in a sedimentary sequence, with reference to common bedding plane structures. Describe how directional sedimentary structures can be utilized to infer paleocurrent directions, paleoenvironmental conditions, and the top/bottom orientation of sedimentary layers. Briefly explain (.any three) : (6x3=18) (i) Relative abundance of major sedimentary rock types. (ii) Diagenetic changes in sedimentary rocks with depth and temperature, including physical, cheriical, and mineralogical transformations.