GBDS

**WELL LOG FACIES DEFINITION AND DEPOSITIONAL INTERPRETATION** **Gulf of Mexico Basin**
REPRESENTATIVE LOG PATTERNS	DEPOSITIONAL SYSTEM AND FACIES ASSOCIATIONS	LITHOFACIES DESCRIPTION	INTERPRETATION	OCCURRENCE IN BASIN	FACIES ASSOCIATION
	Fluvial A. Bedload dominated B. Mixed-load dominated C. Suspended-load dominated	Aggradational facies succession. Sand (A) to mud (C) dominated, heterolithic succession containing discontinuous sand bodies. Sharp basal, variably sharp (A) to transitional, upward-fining (B, C) upper contacts. Laterally discontinuous lithofacies.	Constructional alluvial plain succession landward of delta or shore zone system.	Major fluvial systems source deltaic depocenters. Bed load systems occur primarily in the N.W. Gulf, Rio Grande and Burgos basins. Major fluvial systems source deltaic depocenters. Bed load systems occur primarily in the N.W. Gulf, Rio Grande and Burgos basins.	fbl fml fsl
	Delta Fluvial dominated A. Platform delta B. Shelf-margin delta	Progradational facies succession. Heterolithic composition. Upward coarsening, lenticular, discontinuous sand bodies overlying prodelta mud. Digitate, laterally discontinuous sand bodies.	Major delta system prograding across shelf platform (A) or directly onto the continental slope (B).	Major fluvial-dominated deltas are prominent in the S. Louisiana, Houston and Macuspana depocenters.	dfp dfsm
	Delta Wave-dominated A. Platform delta B. Shelf-margin delta	Progradational facies succession. Sand rich. Upward-coarsening to massive delta margin sand bodies overlying prodelta mud. Tabular to lobate, laterally continuous sand bodies.	Major delta system prograding across shelf platform (A) or directly onto the continental slope (B).	Major delta system prograding across shelf platform (A) or directly onto the continental slope (B).	dwp dwsm
	Shore zone Wave-dominated	Progradational to aggradational facies successions. Sand rich. Upward-coarsening to massive, lenticular to tabular, clean sand bodies. Transitional to sharp base; sharp top.	Constructional shorelines supplied by longshore reworking from major deltaic systems and/or reworking of non-deltaic coastal plain fringes. Includes barrier/ lagoon and strandplain complexes.	Thick shore-zone systems occur in Paleogene through Middle Miocene depisodes.	sz
	Shelf A. Mud-dominated shelf B. Sandy wave-dominated shelf C. Carbonate-dominated shelf Aggradational to progradational blankets and prisms.	Aggradational to progradational blankets and prisms. Sharp to transitional vertical boundaries. Transitional lateral boundaries. Massive to interstratified lithologies. Neritic faunas.	Constructional shelves marginal to major delta systems, fronting shore-zone systems, or capping transgressive coastal successions.	Carbonate shelves and ramps dominate the Florida and Yucatan margins. Relatively thick, clastic shelf systems occur in Paleogene- Miocene depisodes along N.W. and N.C. Gulf margins	sm ss sc
	Slope Progradational delta-fed apron A. Sandy B. Muddy	Offlapping succession of sandy to muddy turbidite and debris flow deposits. Upward-shoaling succession with bathyal faunas. Discontinuous, sharp to transitionally bounded sand bodies. Abundant syndepositional faults. Capped by delta system facies.	Constructional continental margin primarily supplied by a superjacent shelf -margin delta complex.	Front major delta depocenters of N., N.W. and S.W. Gulf.	sbpsd sbpmd
	Slope Progradational shelf-fed apron A. Sandy B. Muddy	Offlapping succession of sandy to muddy turbidite and debris flow deposits. Upward-shoaling succession with bathyal faunas. Discontinuous, sharp to transitionally bounded sand bodies. Capped by shelf system facies.	Constructional continental margin primarily supplied by a superjacent shelf.	Front major shelf and shore-zone depositional system tracts of the N.W. and N.C. Gulf Paleogene- Miocene depisodes.	sbpss sbpms
	Slope Sandy retrogradational slope apron	Onlapping succession of muddy to sandy turbidite, debris flow and slump deposits. Upward-deepening and fining succession with bathyal or mixed faunas. Heterolithic interbedded, discontinuous facies association.	Destructional sandy to heterolithic continental margin undergoing long-term mass wasting.	Locally prominent within OF, PGa, and PAB depisodes.	sbras
	Slope Muddy retrogradational slope apron	Onlapping succession of muddy debris flow and slump deposits. Upward deepening paleobathymetry	Destructional muddy continental margin undergoing long-term mass wasting.	Locally prominent within OF, PGa, and PAB depisodes.	sbram
	Slope Submarine canyon fill	Laterally bounded by deeply incised erosion surface. Dominantly mud fill with lenticular to lobate turbidite channel and lobe sand bodies and discontinuous heterolithic slump and debris flow deposits. Capped by progradational upper slope mud and sandy shelf or deltaic facies.	Large-scale focused mass-wasting and submarine erosion creating a canyon, which subsequently fills with onlapping debris flow and turbidite deposits capped by an offlapping succession of shelf or prodelta sediment.	Locally prominent in the early Paleogene depisodes of the W., N.W. and C. Gulf and in the PS depisode of the N.C. Gulf.	sbsc
	Slope to basin Megaslide complex	Bounded updip at base by slide plane. Rotated fault blocks to chaotic debris apron. Upper progradational facies succession overlies middle muddy unit; turbidite and sandy debris flow deposits and/or disarticulated blocks of upper slope, shelf-margin delta or other shallow facies concentrated in lower part of wedge.	Subregional failure of upper slope and shelf margin creating an embayment or re-entrant in basin margin. Slide blocks and incompletely evacuated debris flow form basal fill. Turbidites and smaller debris flows scour and pond between these. Prograding muddy slope apron deposits heal the embayment.	Locally prominent within OF, PGa, PAB and PTA depisodes.	sbms
	Basin floor A. Basinal mud B. Sand-rich submarine fan Mud; mud with interbedded sand and mud units.	Transitional to sharp upper boundary. Sharp lower boundaries on sand bodies. Bathyal faunas.	Deposition on basin floor by low to high density turbidity currents and fluidal debris flows.	Pentrated only by deep wells in the N.E. and N.C. Gulf margin.	bsbsf