Dear Mrs. Alali,

Sequence boundaries can in this case only be identified by the petrographic and mineralogical manifestos such as encrustations, hardpans etc… attesting to a strong weathering of residual ores and rocks leading e.g. to laterites, bauxites, ore cretes of different kind.

They may contain Fe-Mn encrustations rife with Fe-Mn oxide /hydrates such as goethite, pyrolusite etc. or duricrusts enriched in Al oxide hydrates, e.g., boehmite and gibbsite or certain Ti oxides such as brookite and anatase. Characteristic elements are Ti, Cr, Fe, Mn, Al

DILL, H.G. (2017) Residual clay deposits on basement rocks: The impact of climate and the geological setting on supergene argillitization in the Bohemian Massif (Central Europe) and across the globe.- Earth Sciences Reviews 165: 1-58.

DILL, H.G., WEBER, B. and BOTZ, R. (2013) Metalliferous duricrusts (“orecretes”) - markers of weathering: A mineralogical and climatic-geomorphological approach to supergene Pb-Zn-Cu-Sb-P mineralization on different parent materials.- Neues Jahrbuch für Mineralogie Abhandlungen, 190: 123-195.

DILL, H.G. (2016) Kaolin: soil, rock and ore From the mineral to the magmatic, sedimentary, and metamorphic environments.- Earth Sciences Reviews 161: 16-129.

In these papers you will find further information and papers worth to read.

Kind regards H.G.Dill

first of all , you have to decide what you looking in carbonate as an evidence for sequence boundary..........

Mineralogical studies are used as a supporting evidence with the outcrop / hand specimens

The identificationsvofvthe cly mineral types may differenties between marine and non marine facies.Also the hard ground surfaces onebof the indications .More over the paleosol types ,compositions ,thicknesd considered as good indicatorbof sequnce boundary

.The variations from marine fauna and flora to non marine fauna and flora

also can be used as good indicator.

The identificationsvofvthe cly mineral types may differenties between marine and non marine facies.Also the hard ground surfaces onebof the indications .More over the paleosol types ,compositions ,thicknesd considered as good indicatorbof sequnce boundary

.The variations from marine fauna and flora to non marine fauna and flora

also can be used as good indicator.

The identificationsvofvthe cly mineral types may differenties between marine and non marine facies.Also the hard ground surfaces onebof the indications .More over the paleosol types ,compositions ,thicknesd considered as good indicatorbof sequnce boundary

.The variations from marine fauna and flora to non marine fauna and flora

also can be used as good indicator.