“The Canon balls “ in a sandstone

The name “ Sandy Boy” coined by the colleagues in office stuck like a tooth to a corresponding socket. Sandy Boy was at least fifteen to twenty years older than all the colleagues in the Department. Yet the cool office atmosphere and camaraderie allowed all to pull a leg , here and there. In keeping with the image of the name given, Sandy boy used to wear? outlandish moss coloured or rustic orange T shirts on Friday, signalling the impending weekend ( simply Causal dressing and not advertising a popular brand) which could pass off as a house mop in appearance , any day.

And now, the Canon balls”. “The cannon balls”, which visually looked like a rotund sandstone of average 10cms in diameter, were very heavy when lifted . In every sense they looked like canon balls and felt like one when lifted. Some were as big as 20cms in diameter.

It all started, when “Sandy Boy” went to the Department of Forests in Blackwater group of Islands to seek permission to do research on Khaki coloured sandstones? in several islands including the main island. It was necessary to do so, as 95% of the islands were forest covered and was under the jurisdiction of the same Department. The file went up to the Chief Conservator , who promptly asked Sandy Boy to be called in his chamber. Signing the requisite permission, he said “ we have been curious of very heavy balls of rock all strewn over the beaches in several Islands and were wondering what they are?” “Since you are researching on rocks where these balls are present, I am assigning a speed boat to you tomorrow to reach one of the islands where these? Canon balls are in plenty” , he said. “We would love to know the genesis behind these canon balls”, he said with officious seriousness. While walking out of the office, Sandy Boy observed that along with the giant Hibiscus, Petunia, Lillies etc these Canon balls were also occupying the side of the pebbled road inside the campus.

The next morning , feeling as important as “James Bond on a secret mission”, Sandy Boy ?got up on a new Speed boat , which took him to a small island nearby. The island had very tall trees and dense vegetation in the centre with a beach on one side and vertically dipping rocks with a cliff on the other. ?The moment Sandy Boy got out of his boat on the beach , he was greeted by a prominent signpost mentioning the visit by the highest dignitary of the country. That civilians were not allowed there , was amply clear. Sandy Boy wondered “wow, am I so important?” on seeing the signpost.

Moving towards the cliff, Sandy Boy observed huge vertical faces of khaki coloured sandstones which were massive , thick, sandy turbidites in every sense of the term. In them these “ Canon Balls” were stuck and some lay on strewn on the thin beach below. It was observed that the weathering of the softer , sandstone host rocks, the zone surrounding the “ harder Canon Balls” were impacted by the sea water , rain etc and when sufficient weathering was there, these Canon balls were were just dropping off into the ground from the vertical face of the cliff.

These Canon balls are attributed to secondary diagenetic features called??????????????????????? “ Concretions” , bound tight as a ball by calcareous cement and concentrations of minerals Fe and Mg rich and plenty of Cr. When one of the balls was broken the shiny black appearance was surmised to be from minerals of Fe, Mg, Cr variety in addition to the carbonate cement. All this happening on a subduction zone in a convergent margin where the volcanic arc was close by and the lava contributed to plenty of polymetallic nodules and selective concentration of minerals rich in Fe, Mg ,Cr etc in the sandstones. As to whether the happening of the concretions was taking place under transport and that the Ca ions were attracting the Mg ions can still be speculated at this stage.

Comments, most welcome.