I
visited Gunduperumbedu village near Sriperumbudur last friday, with Gaman Palem and his friend. There were lots of chipped stones
on the ground scattered around a pond, and near a graveyard. It seemed they
have dug up the soil around these parts for building roads, tanks etc and these
stones are deposited all over the place.
I had
gone there after reading an old report in the Hindu that plant fossils were
embedded in these stones. Our friend in Ahmedabad, Ramjee Nagarajan, helped by sending a document, ‘An Integrated Inquiry
of Early Cretaceous Flora, Palar Basin, India,’ published in the journal Phytomorphology,
which was interesting, but difficult to follow, since I was ignorant of
geology, both practical and theoretical.
After
visiting the wrong Gunduperumbedu - there are two, Medu மேடு (Upper) and Pallam பள்ளம் (Lower), the latter with the
fossils, we stumbled upon these. Usually old fossils are buried deep under the
earth and cannot be seen above the surface. In Dholavira, one of the ASI staff
told us that the archaeologists don't pick up and study any pottery on the
surface, as it may be recent. They only study things buried under ground. That
is for a scale of a few thousand years.
Gunduperumbedu - scattered stones on mound |
Close up of stones |
The
paper talked of Cretaceous Flora, which is the geological period, when flowering
plants evolved, about 150 million years ago. But the preamble mentioned pre-angiospermic
flora and plant megafossils!
And
it also mentioned that the Palar basin had:
1. Archaean
deposit - more than 2 billion years ago, before there was cholorophyll or
plants,
2. PreCambrian
layer. The Cambrian “explosion”, 500mya, was the single largest evolutionary
event. There were only three phyla before it, and there are 42 afterwards. It
saw the largest increase in the number of animal species. PreCambrian fossils
are extremely rare.
3. Permian
layers. The end of the Permian period saw the greatest extinction ever: 96% of
all species became extinct.
I dont know if there are actually any excavations that deep or any fossils in that area that old, or merely geological evidence. We certainly did not see any megafossils. Last year, I was planning to visit the Burgess Shale in Canada & perhaps Ediacaran sites in Australia to see pre-Cambrian sites. In Gujarat, I - ok, we - missed out on the dinosaur fossil site in Balasinore. This is a fossil park protected by Geological Survey of India. A large collection of dinosaur eggs was recently discovered in Ariyalur.
The locals
told us that people from Pondicherry and Madras come on weekends and take away stones
and fossils by the sackful. It is a pity there is no archaeological expedition
here. There was once an exhibition in a local school. Local youth scan for
fossils and offer them for sale. One person gave Gaman a stone with a plant fossil and another with
a shell, possibly molluscan, fossil. Gaman became excited, believed that it was
starter’s luck and it paid off – we found a few afterwards. I decided to search
in the shade, and even that strategy paid off. I got one.
But
these are few and far between, and probably not of significant use for serious
research. Some of the technical papers mention exploration around borewells,
probably because researchers here don’t have budgets or equipment or expertise
for excavations. I wanted to post this yesterday, May 21, on Mary Anning's birth anniversary - after seeing her honored with a Google doodle. Her story is fascinatingly similar to our
experience, with far fewer dangers. Her discoveries were accidental, when a
landslide uncovered fossils. She pursued the search for fossils, made it into a
commercial enterprise, came into contact with experts, and so on. The locals
are doing this as a minor commercial enterprise, but land development may
overrun this site. Fortunately, the Sriperumbudur bed is a vast area and the Palar
basin is even larger.
References
1. ‘An Integrated Inquiry of Early Cretaceous Flora, Palar Basin, India,’ published in the journal Phytomorphology, A. Rajanikanth, Anil Agarwal, A. Stephen (stephanos.crown@gmail.com)
2. Mary Anning, Wikipedia page
3. A blog on dino eggs
4. The timeline map of Life - I dont remember what video I captured if from - either a series by Craig Savage or a lecture by Nick Lane. Both are excellent.
Postscript July 15, 2016
In this article, published in the Hindu in 2014, Mr Singanejam Sambandan, Director of the Geological Survey of India, Chennai, has observed that the fossils belong to the Upper Gondwana period, 250 MYA, not Cretaceous 150 MYA, as noted in the title of the first listed reference paper by Rajanikantha, Agarwal, Stephen.
1. Birds & bees evolved only after Mammals. This is not how we were taught in school.
ReplyDelete2. 96% species became extinct after the Permian Period! So most of the current species evolved only 250 MYA or later.
Both these r very interesting pieces of information.
Can i ask one q? When u visit a fossil site, what do u actually see? I thought normally the fossils r taken away for study, dating & research & then displayed in some museum?
ReplyDeleteProfessional paleontologists study fossils at museum. They also dig fossil sites carefully, preserving strata, which they use to date the various fossils and their eras.
DeleteAmateurs can wonder at what the site looks like today, and try to imagine that it was under a sea several million years ago. Imagination is quite powerful