402-pp3 - UNIVERSITY OF SOUTH ALABAMA GY 402: Sedimentary...

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Unformatted text preview: UNIVERSITY OF SOUTH ALABAMA GY 402: Sedimentary Petrology Lecture 3: Sedimentary Rock Classification Last Time A) Basic sediment grain size B) Ternary plots (grain size classification) C) Interpreting grain size data (case studies) D) Grain size parameters (statistics) From: Lewis, D.W., 1984. Practical Sedimentology.van Nostrand Reinhold, New York, 229p. Udden-Wentworth grain size (Wentworth, 1922) Gravel: (>2.00 mm) Sand: (0.063 mm 2.00 mm) Silt: (0.004 mm 0.063mm) Clay: (< 0.004mm) Sand-Silt-Clay Scheme 1 Folk (1954) Symbol Index C-clay; Z-silt; M-mud; S-sand; sC-sandy clay; sM-sandy mud; sZ- sandy silt; cS-clayey sand; mS-muddy sand; zS-silty sand Sand-Silt-Clay Scheme 2 Sheppard (1954) Symbol Index C-clay; Z-silt; S-sand; sC-sandy clay; zS-silty sand; sZ- sandy silt; zC- silty clay cS-clayey sand; szc-sand-silt-clay; cZ-clayey silt Gravel-Silt-Fines Scheme Folk (1954) Symbol Index M-mud; G-gravel; S-sand; sM sandy mud; mS-muddy sand; (g)M-slightly gravelly mud; (g)S-slightly gravelly sand; (g)sM-slightly gravelly sandy mud; (g)mS-slightly gravelly muddy sand; gM-gravelly mud; gms-gravelly muddy sand; gS-gravelly sand; mG-muddy gravel; MsG-muddy sandy gravel; sG sandy gravel Descriptive parameters Source: Blatt, Middleton and Murray (1980) Qualitative (Powers, 1953) Quantitative (Folk, 1980) Roundness (comparison of determination techniques) Today's Agenda 1. 2. 3. 4. Why bother with sedimentary classification? Siliciclastic sedimentary rock schemes Volcaniclastic sedimentary rock schemes Carbonate rock schemes Siliciclastic Rock Classification 1.5 mm FOV, PPL Siliciclastic Rock Classification Particle size classification = energy of deposition 1.5 mm FOV, PPL Siliciclastic Rock Classification Particle size classification = energy of deposition Orthoclase Grain type classification = origin of sediment Porosity Quartz Lithic 1.5 mm FOV, PPL Siliciclastic Rock Classification Particle size classification = energy of deposition Grain type classification = origin of sediment The Problem: Sedimentary rocks come in more "flavors" than any other type of rock. 1.5 mm FOV, PPL How do you classify all of them? Sedimentary Rock Classification Grain size specific and/or... Sedimentary Rock Classification Grain size specific and/or... Particle type specific (e.g. need specific schemes for major sedimentary rocks classes) Sedimentary Rock Classification Particle type specific 1. Siliciclastic sedimentary rocks (Quartz, Feldspars, Clays, Lithic Fragments, Micas, etc.) 2. Shales and Mudstones (grain to "matrix" content) 3. Volcaniclastic sedimentary rocks (vitric fragments and ash, phenocrysts, lithics ) 4. Carbonate sedimentary rocks (skeletal grains, non-skeletal grains and matrix) 5. Organic sedimentary rocks (kerogen content, coal grade etc.) Siliciclastic Sedimentary Rocks (Arenites) Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks (Arenites) Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks (Arenites) Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. GY 402 seal of approval Siliciclastic Sedimentary Rocks Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks Mudstone >75% mud matrix Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks Wackes 15 to 75% mud matrix Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks Arenites <15% mud matrix Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments Siliciclastic Sedimentary Rocks Q = Quartz + chert (sometimes) F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments + chert (usually) Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments Granite mountain Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments Sediment apron Granite mountain Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments 2 cm Granite mountain Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments an "F" grain 2 cm Granite mountain Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments a "Q" grain 2 cm Granite mountain Siliciclastic Sedimentary Rocks Q = Quartz F = Feldspars (orthoclase + plagioclase) R/L = Lithic Fragments an "R" grain 2 cm Granite mountain Volcaniclastic Sedimentary Rocks Source: Carozzi, A.V., 1993. Sedimentary Petrology. Prentice Hill, 263p. Carbonate Sedimentary Rocks Folk Classification Scheme Source: Blatt, H., Middleton, G and Murray, R., 1980: Origin of Sedimentary Rocks. Prentice Hill, 782 p. Blatt, Rocks. Carbonate Sedimentary Rocks Source: Prothero, D.R. and Schwab, F., 1996. Sedimentary Geology. W.H. Freeman, 575 p. Prothero, GY 402 seal of approval Carbonate Sedimentary Rocks Source: Prothero, D.R. and Schwab, F., 1996. Sedimentary Geology. W.H. Freeman, 575 p. Prothero, Equivalent to sandstone/mudstone in siliciclastic rock schemes Carbonate Sedimentary Rocks Source: Prothero, D.R. and Schwab, F., 1996. Sedimentary Geology. W.H. Freeman, 575 p. Prothero, Equivalent to conglomerates in siliciclastic rock schemes Carbonate Sedimentary Rocks Source: Prothero, D.R. and Schwab, F., 1996. Sedimentary Geology. W.H. Freeman, 575 p. No equivalents in siliciclastic rock schemes Upcoming Stuff Homework 1) Writing Assignment 2 (Grain Size hypothesis/methods Due Thursday) 2) Writing Assignment 1-redo (Paper Structure: Due Thursday) 3) Grain Size Analysis Today's Lab Grain Size Analysis Next Lecture: Fluid Dynamics & Grain Size Protocol ...
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This note was uploaded on 02/05/2012 for the course GLY 402 taught by Professor Staff during the Fall '11 term at S. Alabama.

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