The restricted existences of these elements might specify the disturbance by short dry times which favor partial weathering and leaching beneath relatively limy restricted environment.

Regards

Dear Rzger Abdulkarim Abdula 

Thank you for your prompt response

Dear Mrs. Mejjad,

could you please show us a core section illustrating the grain size variation in a variable-width presentation and along with that a downhole plot of the pertinent elements you mentioned above. I think this is a more appropriate way more likely to provide you with a focused answer.

With kind regards

H.G.Dill

Dear Pr. Kenneth M Towe 

The mineralogical analyzes were done for the total sediment, and I calculated the percentage of the minerals in a semi-quantitative way according to Cook et al. (1975).

I found that % of clay minerals (total clay) in the sediment are very low it's between 0.08 and 1.18% 

also the granulometric distribution show a poor  clay content

Dear Mrs. Mejjad,

I hope that my interpretation is correct, because I have only the poor key to the granulometric downhole plot. You are faced with a fining-upward cycle on top, illustrating a decrease vertically upward in the stratigraphic column of grain size and silica sand. The  elements Na, K, Ca, follow suit, Mg, Al, however, do not. The elements are not bound to phyllosilicates but to chemical residues, e.g., bittern salt and/or Ca sulfate, instead. In the middle part of the section  Al remains unaffected, whereas Na, K, and Ca show a strong depletion, in other words, they got washed out, along with a slight increase in Mg. Here I suspect of having a hiatus or break with strong dissolution of the most soluble components above and below. In the footwall the trend reverses. This is not uncommon to a lagoon or an ephemeral lake system.

I am reluctant to try and create an enviornment analysis based upon solely this diagram and over-interpret this diagram.

I hope this brief assessment is of assistance for your studies.

With kind regards

H.G.Dill

There is a relationship between the grain size and abundance of heavy mineral deposits resulting from specific gravity of Heavy Mineral. Due to the specific gravity factor, generally heavy minerals will accumulate in the sediment with sand size (> 2 phi), while REE is more influenced by the source rock.

This can be caused by transportation of sediments from to the sea and action current, wave and tides. The sediments from sea might have been deposited to the shore as swash over the sediments brought from land. so, while drilling the sea sediments will be encountered before the sediment from the land. The process of progradation and retrogradation of sea level can cause the mixture (sand size and heavy minerals). Again, most these element can be dissolve then transported the deep sea through wave, tides and currents thereby rendering the shore or lagoon lesser. 

Dear Mrs. Mejjad

The concentrations you show for major elements are low compared to upper crustal values. If the values are double-checked, it may depend on the source composition.  Are there any contributing streams/rivers to this lagoon. If so, what kind of rocks/geological terrain the stream/river passes through. What is the calcium carbonate content in these sediments?

Sincerely yours

Nagender

 Dear Ernest Chi Fru;

I want to thank you for your prompt response, 

I guess this is the good answer for my question, 

Thank you again

Cordially

N. MEJJAD 

Sediment grain size, in the case of siliciclastics, as a result of variations in energy conditions of deposition, has a perfect control over geochemistry in terms of mineralogical distribution and thus trace and other elemental concentrations. Read the paper by Hart et al. 1998, discrimination of .... published in the Journal of Sedimentary Research. The following papers may also, be helpful to understand the rationale.

  SINGH, P. & RAJAMANI, V. 2001. Geochemistry of Kaveri

flood plain sediments, southern India. Journal of

Sedimentary Research, 71: 50–60.

SHARMA, A. & RAJAMANI, V. 2000. Weathering of gneissic

rocks in the upper reaches of Cauvery River, south India:

implications to neotectonics of the region. Chemical

Geology, 166: 203–223.

SHARMA, A. & RAJAMANI, V. 2001. Weathering of charnockites

and sediment production in the catchment area of

the Cauvery River, southern India. Sedimentary Geology,

43: 169–184.

 Ramkumar, M., Berner, Z. and Stüben, D., 2002 Multivariate statistical discrimination of selected carbonate petrographic classifications: Implications on applicability of classification systems and predictability of petrographic types. Inter.Jour.Geochem.v.62. pp.145-159.

Ramkumar, M., 2007 Spatio-temporal variations of sediment texture and their influence on organic carbon distribution in the Krishna estuary. Ind.Jour.Geochem.v.22.pp.143-154.

Ramkumar, M., 2003 Geochemical and sedimentary processes of mangroves of Godavari delta: Implications on estuarine and coastal biological ecosystem. Ind.Jour.Geochem.v.18. pp.95-112.

Ramkumar, M., Rajani Kumari, V. Pattabhi Ramyya, M. and Vivekananda Murty, M., 2000 Geochemical characteristics and depositional conditions of coastal sedimentary environments of the modern Godavari delta. Ind.Jour.Geochem. v. 15. pp.31-44.

Few of these are available in the researchgate.

All the best.

Mu.Ramkumar