In deltaic system; Very fine to fine grained compact sandstones with planar laminations and no bioturbation. could we consider this a wave or fluvial dominated delta front?
* some intervals of fluid mud (Non bioturbated shales)are observed within the prodelta facies
* only a half HCS observed
* sand intervals are very clean and can form 4 to 5 meters of sandtones
* Some sediment gravity flow and dewatering structures were also observed
Wave dominated or River dominated delta front ???
Waves are an efficient sediment sorter, and move fine-grained sediment offshore while coarser grained sediment is left behind in the nearshore environment. So, wave-dominated deltas are therefore often coarser than tide- or river dominated deltas. Since the study area is made of fine-grained deposits, this, my friend, weakened the possibility of wave- dominated delta?
You might have a combination between the two types of delta?
I hope that this may help.
Dear Colleagues,
to distinguish the three end-member types of deltas (wave-. fluvial-.tide-dominated) should not be done based upon the description of some textures and structures. The delta front is the subaqueous part of the delta which is mainly built up under the influence of marine high energy processes, such as longhshore drift, wave and tidal actions. There may be discordant beds which have derived from fluvial reworking but they have not been mentioned in your record. You excluded a strong tidal impact which could have been indentified by the overall stacking of bedsets. So I assume you are studying currently a wave-dominated part. My general recommendation is try and investigate the entire delta (I do not know how much of it you have insight into ?) plot it and collect all data. The risk to over-interpret one part while others are ignored is high.
With kind regards
H.G.Dill
Walid Abdulqader Saqqa & Harald G. Dill the sediment of the cored section that i investigated is formed by almost 24m (90 percent of it is composed by on top of Very fine to fine sandstone compact with sederite cement and the only sedimentary structures observed is the planar laminations and only 1 HCS). this section overlay directly very deep shales with gaprolithes dated to silurian age. when looking on log pattern and another core upper to this clean sandstones section the delta become more tide affected (hetherolithic sandstone, mud drapes, tiny mud clasts and herringbone cross laminations, climbing ripples and ripple cross laminations in additions to some double mud drapes). so the question was to interpret this basal sand (24 m of VF to F sandsone with planar laminations and no fossils at all). Could you help me on this. Next i will share with you a couple of slides of the cores and log pattern of the whole section. best regards, Wael
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