Dear Dr. Banak,

You may be on the right track but for an in-depth analysis I would like to know some more information, e.g.:

1. Where is this rock positioned along the paleoslope? What rocks are up- and down-slope?

2. What is its upper and lower contact like?

3. How did it debouch and what is its aerial distribution like?

4. What is its extension downslope?

5. You did not see any structural and textural variation.

Are there any lateral facies changes? Currently I am speculating on massing wasting processes in an alluvial to colluvial regime.

With kind regards

H.G.Dill

Well,

Sediment studies on Mesopotamian plain(Iraq) and sediment of Injana and/or Mukdadia Formations can be used for comparison and interpretation.

Sincerely

Dear Adriano,

The fossils indicate the sediment is marine. The texture, poorly sorted with 2-31% gravel points to some catastrophic high energy event, transporting different sizes of sediment, not the normal agent that sorts. The waning of the current must have been instantaneous also, dumping all together without normal sedimentary structures.

The petrography of the pebbles could tell the provenance while the climatic regime (temperate or tropical) could help decipher whether glacial melt water or mudslide of existing bedrock. The thickness of the deposit makes one doubt if sediments were deposited far from shore, and also are dolphins oceanic or near shore dwellers?

Cheers.

Obianuju P. Umeji

Outcrop sub-aerial pictures may please be provided to reach a meaningful conclusion.

With best regards

Ijaz

Dear mr.Dill.

1.it is at the edge of the slope

2.upper is erosional, and lower is not clear

3.not sure for aerial distribution

4.bedrock of miocene limestone

5.No...the sand body is without structures or textures.

This is how it looks like.

I agree with Harald. Sliding processes in a terrestrial environment probably destroyed primary sedimentary structures, and produced the structureles deposits.

The attached photo shows a set of several metre thick beds in the Bad Bentheim area ( Germany) ( Cretaceous age / shallow marine). They are thought to have been laid down as mass flow deposits that originated through the ‘breaching’ ( = collapse of channel banks) of sand-rich shallow marine to estuarine sedimentary system.

Though a thickness of 30 metres is an order of magnitude larger the lack of any sedimentary structure is in my view suggestive of a mass flow mechanism.

The breaching mechanism has also been argued for parts of the Eocene Brussels Sands (Belgium).

Suggest you Google on ‘vandenberghe’ + ‘houtappel’ ?? + Brussels Sands for further info re breaching

Lower and middle section of the profile.

Turbidites have graded beds, the Bouma sequence and so has little possibilities of being the source of this massive deposit. Also, if the texture is pebbly sand, one would not say the deposit has no texture.

Obianuju P. Umeji

Picture is not clear to me.

For me looks as a lacustrine deposit, may be. Require some information on grain type/size.

May be weathering and erosional product of Rhyolite (volcanic rock).

Jorge,

I absolutely agree with you concerning the Bouma cycle. I just thought to make these two points which might be oversight. The effort is to tackle the question you posed.

Good work.

Obianuju P. Umeji

Jorge,

I absolutely agree with you concerning the Bouma cycle. I just thought to make these two points which might be oversight. The effort is to tackle the question you posed.

Good work.

Obianuju P. Umeji

Thank you all for you answers and contribution.

Dear Adriano,

further to my previous reply I attach a couple of photographs of presentation slides that I took during an academic symposium I attended today. The presenter discussed structureless ‘breach deposits’ in an Jurassic oil reservoir in the Norwegian sector of the North Sea + modern day analogues that form quite frequently in active estuaries in the SouthWest Netherlands. What is of interest with respect to your own example of a 30m thick structureles bed is that the oil field example is of a similar thickness.

The quality of the photos is rather poor as they are shots of a projection screen taken under poor lighti G conditions and from an oblique position. Nevertheless the relevant details are clearly discernable.

Dear W.J.E.Van de Graaff thank you so much for sharing this with me.

From all the discussion it seems the consensus is centered around a mass-transport deposit that left the erosional remnants of a scar and carried older deposits and fossils as it moved en masse with laminar flow and was deposited as a slump or a slide on the upper paleoslope.

Dear Adriano,

I am not coming up with an answer but rather with a question. I have come across many similar sand bodies in the Pannon basin, that have been assigned to various ages with very few (sometimes no) argumentation behind.. How solid is the age model and what is it based on?

_ I will be in the field for 20 days with no internet but I am looking forward on following-up this conversation.

Dear Dan. Age model is done with cosmogenic nuclides. We are doing it one more time, to confirm lower Pleistocene.

Good luck with field work!

Adriano

Could you, please, give exact coordinates of the deposit?

Dear Mr. Banak, I have reconsidered your question and would like to make two additional remarks. You should in this case not only base your genetic ideas about observations of the outward appearance at outcrop but also try and investigate the microstructures. If it is an unconsolidated sediment lacquer-peels may be a good tool to obtain undistorted sediment samples. Maybe you can get more information. Your hint to a strong amount of fossil detritus made me suspect of bioturbation. Currently it is not anything but a hint which needs further evidence in one or the other direction. H.G.Dill

Dear Harald G.Dill, thank you for your additional answer. I will take more, new samples and try to figure it out. Best regards.

Dear Banak,

If I understood your opening statement above correctly I suggest there are sources for the sandstone. They are:

1. Pleistocene sand grains plus gravel, possibly from nearby recent igneous source

2. Fossil remains (fish bones, dolphin bones) from a nearby older sediments (Pliocene and Badenian) may have been reworked and embedded.

Understanding the regional tectonostratigraphic history of the basin may help.

Are there any similar deposits elsewhere in the region? Is it localized or regional?

Good luck