402-pp6 - UNIVERSITY OF SOUTH ALABAMA GY 402: Sedimentary...

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Unformatted text preview: UNIVERSITY OF SOUTH ALABAMA GY 402: Sedimentary Petrology Lecture 6: Primary and Diagnostic Sedimentary Structures Last Time 1. What's a flume? 2. Traction induced bed forms (sedimentary structures) 3. Flow regime Sediment loads Sediment moving along the base of a channel* that mostly stays in contact with the substrate is called... Current Bed load saltation rolling sliding Types of bed load transport (traction) Flume Studies Increasing current velocity under controlled situations (fixed water depth, constrained grain size) yields the following structures: Plan lamination (lower) Small current ripples Large current ripples (dunes) Plan lamination (upper) Antidunes Increasing water velocity Flume Studies current Add a current.... .... Observe! Flume Studies: 2) summary ripple morphology From Collinson, J.D. and Thompson, D.B. 1982. Sedimentary Structures. George Allen & Unwin, 194p. Collinson, Allen Unwin, Flume Studies: 2) small current ripples Dune fraction Bypass fraction Flume Studies: 2) small current ripples Migration direction Ripple co-set Flume Studies: current ripple crest morphology increasing velocity (or decreasing water depth) straight sinuous linguiodal From Collinson, J.D. and Thompson, D.B. 1982. Sedimentary Structures. George Allen & Unwin, 194p. Collinson, Allen Unwin, Flume Studies Collinson, Allen Unwin, From Collinson , J.D. and Thompson, D.B. 1982. Sedimentary Structures. George A llen & Unwin , 194p. Plan lamination (lower) Small current ripples Large current ripples (dunes) Plan lamination (upper) Antidunes Chutes & pools (erosion) Increasing velocity Today's Lecture 1. Models of traction structures 2. Sediment transport versus aggregation 3. Wave ripples 4. Erosional features 5. Surface features 6. Intrusive (dewatering & loading) structures 7. Really diagnostic structures (just a couple!) Models of Traction Structures 1) Small current ripples Models of Traction Structures 1) Small current ripples 30 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Models of Traction Structures 50 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Models of Traction Structures s Crest e Rippl From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Models of Traction Structures 1) Small current ripples current 15 cm Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary 1975. Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2. 2. Models of Traction Structures 1) Small current ripples (Linguoidal) 10 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Models of Traction Structures 1) Small current ripples (lunate) 30 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Reineck, H.Environments. Springer-Verlag, Berlin. 549p. Springer- Verlag, 100 cm Models of Traction Structures 2) Large current ripples 50 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, 100 cm From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from R.G., Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2. 2. Models of Traction Structures Be careful! Erosion removes bed form topography 30 cm 75 cm From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted from Primary R.G., Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2. 2. Migration versus aggregation Migration versus aggregation current aggregation migration Transport versus aggregation 30 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Transport versus aggregation hor izo n Transport versus aggregation hor izo n D ep ositi surf onal ace Transport versus aggregation Climb angle hor izo n D ep ositi surf onal ace Wave ripples Wave ripples Form through the action of "orbicular flow" Wave ripples From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Wave ripples Crossstratification records aggregation versus transport From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Erosional structures Erosional structures Rip up clasts Erosional structures Rip up clasts Scours Erosional structures Rip up clasts Scours Channels Reineck, H.Both from Reineck , H. -E. and Singh, I.B. 1980. Depositional Sedimentary Springer- Verlag, Environments. Springer -Verlag , Berlin. 549p. Scours Channels Erosional structures Rip up clasts Flute marks Surface view Erosional structures Rip up clasts Scours Channels Flute marks Under bed view From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Erosional structures Rip up clasts Scours Channels Flute marks Tool marks From Lucchi, F.R.,1995. Sedimentographica. Second Edition. Columbia University Press. 255p. Lucchi, Sedimentographica. Surface features Surface features Rain drop imprints Ancient (Triassic) Raindrop imprints in shale http://home.entouch.net/dmd http://home.entouch.net/dmd Surface features Rain drop imprints Mudcracks Ancient (Triassic) Modern 75 cm http://www.bedford.k12.ny.us/flhs/science/geoscience/images/mudcrackssample.jpg http://www.bedford.k12.ny.us/flhs/science/geoscience/images/mudcrackssample.jpg Surface features Rain drop imprints Mudcracks Beastie trails Modern Ancient (Silurian) 40 cm http://www.fossilmall.com/Stonerelic/trace%20fossils/DD39/DD39c.jpg http://www.fossilmall.com/Stonerelic/trace%20fossils/DD39/DD39c.jpg Surface features Rain drop imprints Mudcracks Beastie trails Parting lineations Ancient (Permian) Modern 75 cm http://ic.ucsc.edu/~casey/eart150/Lectures/Foliations&Lineations/PartingLinParrsbourghNS.jpg http://ic.ucsc.edu/~casey/eart150/Lectures/Foliations&Lineations/PartingLinParrsbourghNS.jpg Intrusive structures Lucchi, Sedimentographica. From Lucchi , F.R.,1995. Sedimentographica . Second Edition. Columbia University Press. 255p. Loads Intrusive structures Loads Reineck, H.From Reineck , H. -E. and Singh, I.B. 1980. Depositional Sedimentary Springer- Verlag, Environments. Springer -Verlag , Berlin. 549p. Ball and pillows Intrusive structures Intrusive structures Loads Ball and pillows Sand dykes (dewatering) Intrusive structures Loads Ball and pillows Sand dykes Mud volcanoes 20 cm 3m Both from Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Intrusive structures Loads Ball and pillows Sand dykes Mud volcanoes Monroes 20 cm From Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Reineck, H.Springer-Verlag, Berlin. 549p. Springer- Verlag, Really diagnostic sedimentary structures Really diagnostic sedimentary structures 1) Beach environments Really diagnostic sedimentary structures 1) Beach environments Low angle crossstratification Both from: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional Environments as Interpreted Walker, from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2. 2. Really diagnostic sedimentary structures 2) Muddy tidal environments Really diagnostic sedimentary structures 2) Muddy tidal environments flaser bedding wavy bedding lenticular bedding All from Reineck, H.-E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer-Verlag, Berlin. 549p. Reineck, H.Springer- Verlag, Really diagnostic sedimentary structures 3) Sandy tidal environments Really diagnostic sedimentary structures Reineck, H.From Reineck , H. -E. and Singh, I.B. 1980. Depositional Sedimentary Environments. Springer -Verlag , Berlin. 549p. Springer- Verlag, Herringbone crossstratification 3) Sandy tidal environments Really diagnostic sedimentary structures 4) Deep marine environments (below wave base) Lucchi, Sedimentographica. From Lucchi , F.R.,1995. Sedimentographica . Second Edition. Columbia University Press. 255p. 4) Deep marine environments (density currents) Really diagnostic sedimentary structures Turbidites Really diagnostic sedimentary structures 4) Deep marine environments (density currents) Graded bedding HCS (hummocky cross-stratification) From: Harms, J.C., Southard, J.B., Spearing, D.R. and Walker, R.G., 1975. Depositional R.G., Environments as Interpreted from Primary Sedimentary Structures and Stratigraphic Sequences. SEPM Short Course 2. 2. Upcoming Stuff Homework 1) Data plotting exercise (due today: no redo) 2) Writing Assignment 2-redo (Grain Size hypothesis/methods): Due Today 3) Grain Size Analysis introduction/results: Due next Thursday (2:00 pm) Today's Lab Finish up grain size analysis Next Lecture/Lab: Sedimentary Sections Bogus Section activity (lab and writing assignment) ...
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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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