Appendix D

Architectural elements and lithofacies classification

Facies code	Lithofacies	Sedimentary structures	Interpretation
Gms	massive, matrix supported gravel	grading	debris flow deposits
Gm	massive or crudely bedded gravel	horizontal bedding, imbrication	longitudinal bars, lag deposits, sieve deposits
Gt	gravel, stratified	trough crossbeds	minor channel fills
Gp	gravel, stratified	planar crossbeds	linguoid bars or deltaic growths from older bar remains
St	sand, medium to v. coarse, may be pebbly	solitary (theta) or grouped (pi) trough crossbeds	dunes (lower flow regime)
Sp	sand, medium to v. coarse may be pebbly	solitary (alpha) or grouped (omikron) planar crossbeds	linguoid, transverse bars, sand waves (lower flow regime)
Sr	sand, very fine to coarse	ripple marks of all types	ripples (lower flow regime)
Sh	sand, very fine to very coarse, may be pebbly	horizontal lamination, parting or streaming lineation	planar bed flow (l. and u. flow regime)
Sl	sand, fine	low angle (< 10 degrees) crossbeds	scour fills, crevasse splays, antidunes
Se	erosional scours with intraclasts	crude cross-bedding	scour fills
Ss	sand, fine to coarse, may be pebbly	broad, shallow scours including eta crossbedding	scour fills
Fl	sand, silt, mud	fine lamination, very small ripples	overbank or waning flood deposits
Fsc	silt, mud	laminated to massive	backswamp deposits
Fcf	mud	massive, with freshwater molluscs	backswamp pond deposits
Fm	mud, silt	massive, dessication cracks	overbank or drape deposits
Fr	silt, mud	rootlets	seatearth
C	coal, carbonaceous mud	plants, mud films	swamp deposits
P	carbonate	pedogenic features	soil

Model 6--the classic sandy, mixed-load meandering river.

Architectural elements in fluvial deposits

Element	Symbol	Principal lithofacies assemblage	Geometry and relationships
Channels	CH	any combination	finger, lens or sheet; concave up erosional base; scale and shape highly variable; internal concave-up secondary erosion surfaces common
Gravel bars and bedforms	GB	Gm, Gp, Gt	lens, blanket; usually tabular bodies; commonly interbedded with SB
Sandy bedforms	SB	St, Sp, Sh, Sl, Sr, Se, Ss	lens, sheet, blanket, wedge; occurs as channel fills, crevasses, splays, minor bars
Foreset macroforms	FM	St, Sp, Sh, Sl, Sr, Se, Ss	lens resting on flat or channelled base, with convex-up second-order internal erosion surfaces and upper bounding surface
Lateral accretion deposits	LA	St, Sp, Sh, Sl, Se, Ss; less commonly Gm, Gt, Gp	wedge, sheet, lobe; characterized by internal lateral accretion surfaces
Sediment gravity flows	SG	Gm, Gms	lobe, sheet; typically interbedded with GB
Laminated sand sheets	LS	Sh, Sl; minor St, Sp, Sr	sheet, blanket
Overbank fines	OF	Fm, Fl	thin to thick blankets; commonly interbedded with SB; may fill abandoned channels

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