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Lecture 5: Sedimentology: a refresher on rivers, deltas and shallow
marine sediments
.
Models of Basin Fill
…….two key texts….. CD…..rivers, deserts, estuaries, deltas, shorelines, shelves, deep sea
Examine and reviewthese sedimentary environments……………….
•Briefly•wrtWestern Eire•Allied Sedimentology GEOL440 notes on website
Deltas
Bhattacharya 2006
Bhattacharya 2006
Bhattacharya 2006
Bhattacharya 2006
Peyto Lake Canada
Bhattacharya 2006
Bhattacharya 2006
Bhattacharya 2006
Prograding mouth bar succession
Homogenous mud, finely laminated or bioturbated, marine fauna… representing shelf deposit
Silty/sandy slump sheet… representing redeposited(distal) mouth bar sediment
60-1
50 m
Finely laminated mud, bioturbation, marine fauna, contorted bedding… representing prodelta deposit
Interbedded mud/sand, wave & current ripple x-lam., parallel/lenticular lam., bioturbation,
contorted bedding, possible cut & fill… representing distal mouth bar deposit
Well-sorted sand, planar & ripple x-lam., tangential x-bedding (bar crest); poorly sorted sand/silt, cut & fill, small-scale trough x-bedding (bar back); large
channel fills near top (distributary channel)
Clean sand, low- & high-angle 3D strat.… representing beach & dune deposits
Mississippi delta
Danube Delta
Ganges-Brahmaputra delta, Bangladesh 100 km
Tide‐dominated delta facies successionOrd River delta, Australia
Bioturbated mud passing into interbeddedmud‐silt‐sand, marine fauna
... representing open shelf to prodelta succession
Bidirectional x‐bedded sand, mud drapes, tidalbundles, reactivation surfaces, scours/channel fills
... representing migrating tidal current ridges& inter‐ridge channel fills on delta front
Alternating sand‐silt‐mud, x‐lam., “flaser‐linsen”bedding, small channel fills, brackish‐water fauna
... representing tidal flat facies on delta plainErosive, FU sand with herringbone x‐strat., mud
drapes, tidal bundles, ripple x‐lamination... representing tidal channel on delta plain
Bhattacharya 2006
Pulham 1989
Delta?Delta type?
Basinal processes?Flow depths?Paleoflow?
Allo and auto cyclic controls
Boyd et al., 2006
Boyd et al., 2006
Major clastic coastal environments
Shoreline accumulation through progradation
Clifton, 2006
Beach - Offshore
Clifton, 2006
TraceFossils
USC website
Body and trace fossils……
Clifton, 2006
Sea‐levelcontrol on facies
Clifton, 2006
Clifton, 2006
Shallow marine/shoreface?Basinal flows?
Cyclicity
Rivers
Bridge, 2006
Rivers ‐channel scale
Bridge, 2006
Bridge, 2006
Bridge, 2006
Bridge, 2006
Bridge, 2006
Bridge, 2006
Williams & Soek, 1993
Channel type?Paleoflow?
Channel stacking?Controls?
References
See GEOL440 Sedimentology lectures (see website)Chapters by Bridge, Bhattacharya, Clifton and Boyd et al., in Facies Models Revisited
Davies, S.J. and Elliott, T., 1996, Spectral gamma ray characterization of high resolution sequence stratigraphy: Examples from upper Carboniferous fluvio‐deltaic systems, County Clare, Ireland, in Howell, J.A., and Aitken, J.F., eds., High resolution sequence stratigraphy: Innovations and applications: Geological Society of London Special Publication 104, p. 25‐35.Pulham, A.J., 1989, Controls on internal structure and architecture of sandstone bodies within Upper Carboniferous fluvial‐dominated deltas, County Clare, western Ireland, inWhateley, M.K.G., and Pickering, K.T., eds., Deltas: Sites and traps for fossil fuels: Geological Society of London Special Publication 41, p. 179‐203.Williams, H., and Soek, H.F., 1993. Predicting reservoir sandbody orientation from dipmeter data; The use of sedimentary dip profiles from outcrop studies, in Flint, S.S., and Bryant, I.D., eds., The geological modelling of hydrocarbon reservoirs and outcrop analogues: Special Publication of the International Association of Sedimentologists, v. 15, p. 143‐156.
Next week
•basinal shales, turbiditesand deep‐sea sediments BUT…………………………