Well 4FACIES ASSOCIATIONS ENVIRONMENTAL INTERPRETATIONFA8:

Dominated by medium to coarse, pervasively bioturbated sandstones with thin layers of unbioturbated white sandstone.

Overall aggradational Rare influxes of black mudstone Planar, trough and high-angle laminated cross-bedded Rootlets, Ophiomorpha, abundant Skolithos Soft sediment deformation

Presence of rootlets suggests the influence of a terrestrial environment

Soft sediment deformation suggests a period of high sedimentation rate – compaction of unlithified sediments

High bioturbation and sandy siliciclastic facies suggests a near shore/beachfront environment

Most likely to be delta plain environment, evidenced by mud flats (rootlets), tidal channel and near shore depositional environments

FA7: Planar, cross-bedded and ripple cross-laminated medium

to coarse sandstones Overall slightly fining up Numerous vertical escape burrows Ripple cross-laminations

Both planar and ripple cross laminations suggest a unidirectional flow current, in alternating lower regime (cross-beds and ripples)-upper regime (planar lamination) flow conditions

Numerous vertical escape burrows suggest high sedimentation rate

Possible isolated river/tidal channel within the delta plain

FA6: Dominated by bioturbated medium to coarse sandstones Ophiomorpha ichnofacies throughout, rare fragmented

bivalve bases Increasing bioturbation with decreasing grain size Partially fining upward at base of association Sometimes interbedded with mudstones and clean low-

angle cross-laminated siliciclastic sandstone layers

Massive graded beds of bioturbated quartz sand, lenses of weakly laminated clean quartz sand and high angle cross lamination suggest a shoreface environment

However, a small layer of mud observed at the top of the FA has small sand flasers and lenticular bedding which may be indicative of a tidal environment.

FA3: Repetition of FA3 Slightly more pervasively bioturbated sandstone Less muds

See FA3 environmental interpretation below

FA5: Dominated by fine to medium, planar and cross-laminated

sandstones Broadly aggradational with fining up trends Diplocraterion throughout association Repeated pattern of planar laminations to low-angle cross-

laminations with bioturbated tops

FA4: Erosive surface at base of association Dominated by thick black mud layer and heterolithic

mudstone-sandstone Woody material and Thalassinoides

Presence of Diplocraterion suggest high sedimentation rates

Clear fining up trends within planar to cross-bedded fine to medium sandstones that may suggest channel fill deposit

Mix of both terrestrial (woody material) and marine (Thalassinoides) indicators throughout, along with heterolithic sandstone-mudstone suggest an overall tidal/estuarine environment

Thick mud unit may have been deposited during an extended period of low energy

Well 4 (cont.)FACIES ASSOCIATIONS ENVIRONMENTAL INTERPRETATIONFA3:

Dominantly heterolithic mudstone-rudstone, some pervasively bioturbated sandstones at base

Rare mud rip-up clasts Alternating sandstone, mudstone, carbonate units Sharp transitions between rudstones and mudstones with

minor scouring

Higher energy clasts (disarticulated bivalves) within a mud matrix – dominantly lower energy environment with periodic high energy influxes below the wave base (storm event)

Could also possibly be deposited down slope (muddier facies) from a carbonate producing platform

Sharp transitions and minor scouring suggests Similar depositional environment to FA1, however

transition of rudstone to floatstones are not observed in this FA.

Delta front slopeFA2:

Dominantly planar-laminated sandstones with bioturbated tops

Bioturbated heterolithic mudstones and sandstones in centre of association with mud rip-up clasts

Woody material scattered throughout Periodic occurrences of mudstone layers (variable

thicknesses) Thalassinoides, Diplocraterion Slight fining up trend at base of association

Dominance of sandy facies with common muddy laminae and heterolithic mudstone-sandstone suggests alternating energy conditions

High sedimentation rate suggested throughout by presence of Diplocraterion

Mix of woody material (terrestrial) and Thalassinoides (shallow marine), strong bioturbation and heterolithic suggests tidal/estuarine environment

FA1: Broadly coarsening up, grading from mudstones to coarse

sandstones Alternating layers of massive mudstones, bioturbated fine

sandstones and carbonates Carbonate layers transition from rudstones to floatstones

at the top. Disarticulated bivalves at bases of rudstones Sharp contacts and pervasive bioturbation in sandstones

Transition of rudstone bases to floatstone tops suggest a decreasing energy flow within the carbonate units

This may suggest that the bivalves (broken up/disarticulated) have been flushed into a lower energy, muddier environment such as a delta slope during a possible storm event

Sea Level Change Interpretation FA4 - delta plain (higher flow) (skipped delta platform - erosional surface)