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Assalaam O Alaeekum Sir, I need to know a few examples of such sedimentary structures which have purely tectonic origin. At what scale such structures can be observed during field and thin section study? Are these structures effective to infer the tectonic evolution of a sedimentary basin, locally or regionally for the time of deposition of that sedimentary unit? If it requires explanation, Please suggest some literature.
Jazaak ALLAH Sir!


As per definition the sedimentary structures are those structures, which are formed during sediment deposition. The main sedimentary structures are cross-bedding, ripple-marks, mud-cracks, graded-bedding, concretions, nodules, bio-turbation etc. As the above definition of sedimentary structures suggests, they do not have tectonic origin.

These features have a wider scale range and can be observed from mega to micro level i.e both in the field and in the thin section. However, ripple-marks and mud-cracks can be observed in the field only.

They can be of indirect help to infer the tectonic history. For example if a ripple-marked surface is overlain by deposits of deep water origin then one can infer a sudden rise of sea level or sinking of terrain due to tectonic activity. The same you can apply to overlying and underlying sediments with  reference to different type of sedimentary structures, if present. This will help you evolve the tectonic history in vertical sense.  


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Nusrat Kamal Siddiqui (Mr)


I am a petroleum exploration geologist with about 40+ years of diversified experience. I can answer questions on stratigraphy, log interpretation, field studies based on set of logs and core results, general geology etc. Can provide guidance for career planning in earth sciences. Can not help in questions about hard rocks, igneous petrology & mineralogy, sequence stratigraphy and seismic.


Petroleum Exploration - field geology, stratigraphy, prospect generation, interpretation of satellite imagery (visual), log interpretation.

Retired in May, 2006 as Senior Manager Exploration from Pakistan Petroleum Limited after serving 26 years. Since then continuing in active service with petroleum exploration companies.A cumulative experience of about 40 years covers 30 years in petroleum exploration, 5 years hydrogeology experience in Libya, and about 5 years of dam geology in Pakistan.

-AAPG Bulletin (Vol.88, July, 2004); paper on Sui Main Limestone (Eocene), a prolific gas reservoir in Pakistan. -Have presented papers on diversified topics ranging from spirituality, flood control, remote sensing and off course geology in France, Nepal, Bangladesh, Sri Lanka, UAE, Kashmir, India and Pakistan that have been published in respective Special Proceedings. -ONGC Bulletin(India) Vol. 44, Number 2, December, 2009; Chapter 19.A & 19.B on basin architecture and stratigraphy of Pakistan, p.402-474.

BSc Honours in Geology and Master of Science in Petroleum and Structural Geology. PGD from ITC, The Netherlands.

Awards and Honors
-Remained Active Member of AAPG from 1990-2006; founding member of PAPG (a local affiliate of AAPG). -Life member of SEGMITE & AGID, and Senior Editor of SEGMITE magazine. -Member of the Board of Studies, i. Department of Petroleum & Gas Engineering (BUITMS, Quetta), and ii. Geology Department, Sindh University, Jamshoro. -Member of Stratigraphic Committee of Pakistan. -Represented Mining Journal, UK in Pakistan till 2007. -Chairman of Annual Technical Conference (ATC)& Oil Show, an SPE/PAPG annual event, in 2003. -Chairman Technical Committee (ATC, 2002).

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