ON THE TRAIL OF GOA'S PLANT MEGAFOSSILS
I have a piece of fossilized or silicized wood which was found during 1966-67 while building an approach road on Borim’s Siddanath hill. How fossilized wood can be found at such an altitude?. Except NIO’s Dr. Rajiv Nigam no scientist has paid any consistent attention to research on Goa’s marine fossils which are still being mined for making mortar. The criminal neglect of fossils in Goa shows how little we care for challenging research. We should feel ashamed that after 1876 neither the government -Portuguese or Indian, nor the scientists and academicians followed this interesting lead which would have put Goa on world map of plant megafossils and could have boosted tourism in western ghats. Isabel, Lady Burton (1831 -1896) — née Isabel Arundell — was the wife and partner of explorer, adventurer, and writer Sir Richard Francis Burton (1821-1890). Sir Richard Burton had visited Goa and had written an account-Goa and the blue mountains in 1851. But the great adventurer missed what his wife later found. Lady Burton’s visit took place somewhere in 1875-6. This is how she described her experience of visiting a site of petrified forest in Goa -“We made two boat expeditions together -- one to see a coffee plantation, in which is a petrified forest. Each expedition occupied two or three days. We embarked for the first in a filthy boat, full of unmentionable vermin, and started down the river in the evening, with storms of thunder and lightning and wind precluding the monsoon. On arrival we toiled up two miles of steep, rocky paths through cocoa groves. At the bottom of the hill was a little rivulet, and pieces of petrified wood were sticking to the bank. As we ascended the hill again we found the petrification scattered all over the ground; they were composed chiefly of palms and pines; and most interesting they were. “ (Source: Burton, Lady Isabel (1831-1896).Wilkins, W. H. (1860-1905). The Romance of Isabel Lady Burton Volume II, The Story of Her Life, Told In Part by Herself and In Part by W. H. Wilkins. Chapter 22). After 136 years I was probably following her trail blindly on an unusually warm November afternoon. This is a short report on my discovery of a new and exciting location of petrified forest-meaning plant/tree megafossils in Goa. This is not the same location reported by some fossil hunters in May 2012. They were actually confirming another 1876 report. I have inspected that location also and obtained samples for studies. Goa is land of micro, macro and megafossils. Marine fossils are plundered from Camurlim, Tuem, Agapur for making lime. Marine fossils are also located near Mapusa river. Sancoale or Shankhavali derives its’ name from fossilized marine conches and windowpane oyster shells found in the soil there. There is belt of marine fossils from Cortalim to Chikhalim and Bambolim to Siridao on both the banks of Marmagoa bay. Since the trained scientists, except NIO’s Dr. Nigam and his student have not cared to study these and such sites I was compelled to undertake the field and lab investigations. Work done by Dr. Nigam’s students on marine fossils of Konkan showed relict presence of T. squamosa. They explained it by the fact that it resided in this area and got encrusted on foraminiferal tests when the sea level was lower at ca. 10,000 yrs BP, thus indicating that at ca. 10,000 yrs BP, the Konkan shoreline was 80 m lower than that at present. No historian in Goa has understood the implications of such lower sea level for human migrations. The finding was published in January 2013 issue of GOA TODAY because there is an unhealthy and unethical competition to take false credit. I experienced it when rock art gallery was discovered in May 1993 at Usgali/Panasaimal,Kolamb, Rivona (Goa Today, June 1993). Hoards of fossil hunters may descend in Goa after publication of this article. Goa has violent tectonic past which resulted in rocks being folded and faulted, rivers changing their courses and entire forests becoming petrified. The legend of Parashurama abstracted these events. Portuguese suspected it. Lopes Mendes mentioned it. German geologist Oertel believed it. Anant Dhume was first historian to point to marine fossils in Sattari. He found a marine conch at Thane, Sattari and hinted at fossils at Ivrem khurd and budruk villages. He had even donated a petrified root specimen to Goa museum where it is not now traceable. During 1966-8, a road construction was undertaken on Bori hill. Mr. Percival Noronha, the then director of tourism, found fossilized tree trunks and petrified logs by the roadside and managed to retrieve a sample which he later gifted me. It was identified by Goa University geologists as silicized wood. However, no expert on geology of Goa could explain to me how plant megafossils could be found at an altitude of several hundred metres from present sea level. Then in upper reaches of Mhadei river basin I could detect rare fossilized stromatolites, the most ancient photosynthetic marine bacteria on earth, in photographs taken by Mr. Prakash Poreinkar during a three day trek to the source of river. This was first report of such ancient microfossils (http://www.navhindtimes.in/panorama/neglected-stromatolite-fossils-goa) anywhere on west coast and western ghats of India. During my field trip in November 2012 for specific investigations of petrified forests reported by British geological adventurers in Sattari (Marchesetti, C. D. On a Pre-historic Monument of the Western Coast of India. Journ. Bombay Branch B. As. Soc. vol. xii. pp. 215-218. 8th April 1876) guided by Prakash Porienkar, I discovered on the banks of Mhadei river and in the semi dry channel as well at a location called – JAGHDHA ( location name changed) thousands of sq. mts of petrified forest comprising huge horizontally piled up petrified tress possibly monocots. The local rock formation is Vageri meta-greywacke/metabasalt in a banded Iron formation zone. The dating is difficult and would be shortly done by Birbal Sahani institute experts. B massive and deeply layered , richly textured, very hard but brittle plant megafossils are different than 20 million years old petrified trees found at the National Fossil Wood Park in Thiruvakkarai, located about 35 km from Puducherry. These belong to what is called the ‘Mio-Pilocene' age. GSI experts say that the these fossil woods was the result of a huge flood that occurred millions of years ago and destroyed large parts of forests in the adjoining area. The flood story for Goa is unknown. However going by the hard metabasaltic nature the the JAGHDHA , Sattari fossils may be as old as fossils of Akal Fossil Wood Park, Jaisalmer . These petrified wood carries signature of the luxuriant forests in a warm and humid climate, bordering the sea some 180 m.y. ago. The fossils are of petrophyllum, ptyllophyllum, equisetitis species and dicotyledonous wood and gastropod shells of Lower Jurassic period. The JHADHA Sattari megafossils also differ from the petrified specimens in National Fossil Wood Park in Sattanur, Perambalur District which contains large trunks of petrified trees of Upper Cretaceous age (100 m.y). The trees belong to conifers (non-flowering) that dominated the land vegetation during the period. The fossilised tree trunk at Sattanur measures over 18 m in length. The JHAGHDA petrified trees are horizontally piled up, and extend several metres in the river channel. The petrification event may be associated with the violent tectonic event of change in the course of Mhadei river. Experts have opined that this area was a geological high ( at least above 800 metres) when volcanism in Deccan, 63-66 million years ago formed the flood basaltic plateau. Fossil specimens which I have examined in laboratory clearly showed intact petrified vascular bundles, a lot of pyrite ( Iron sulphide) , black sulphides of Gold, silica grains and auriferous quartz. On basis of ecological, hydrological, local geological evidence and mineralogical basis, I wish to tentatively date these megafossils to 100-180 my may be more but dating is tricky and expert confirmation is awaited. My attempts since November 24 to contact the Chief Minister and arrange his visit to this sensational fossil site failed. I would try again. Only he can issue proper orders. The easily accessible and unprotected area needs surveillance otherwise within no time it would be plundered. A more detailed report would be published in this magazine later. The local village panchayat, the forest, the water resources department and collector, north Goa should take steps to protect this site immediately. It is actually a continuous belt of massive petrified forest extending from Bhironda to Khotodem and exposed only by the channel of river of Mhadei. The part which is buried is difficult to trace but may be exposed in trial trenches. We need to be grateful to Lady Burton for awakening us. Here is the nucleus for Goa’s new geological park.
