Gulf of Cambay Cradle of Ancient Civilization (cont.)
By Badrinaryan Badrinaryan
Magnetic surveys were carried out by deploying a high resolution Marine Ceisium vapour Magnetometer. The survey was for observing magnetic signature occurring as anamolies of subsurface magnetic bodies of the area. The instrument was capable of sensing upto 0.001 nT at 1 sample rate. The values here were corrected for diurnal variation so as to remove the temporal variation in the earth’s magnetic field. The corrected magnetic field value is a result of the marine magnetic components :- regional geological features are very deep seated in origin and have depth persistence whereas one should look for very shallow and near seabed anaomolies that do not extend in depth. Several shallow near surface anomalies were picked up ranging in depth from 1m below surface to as much as 50m. The deep seated anomalies are atleast below 400m from the seabed surface. The near surface anomalies in general are covered by top sediments and are likely to be archaeological sites which are to be examined and explored later. Due to these surveys a vast area has now acquired importance for archaeological purposes – including areas that were earlier not picked up by sidescan images. As such these surveys enhance the area of archaeological interest. Obviously this was an extensive civilization, the remains and ruins of which have since been covered by shifting shoals, sandwaves, tectonism etc., which are very common features in the Gulf of Cambay.
Figure – 14
Figure – 15
Figure – 16
Even though a variety of objects and artifacts were collected in settlements, doubts were expressed by some persons whether these could have been transported by paleochannel and may not be insitu. To clear such doubts detailed geochemical analysis were carried out. Ten geological soil samples and ten artifacts were chosen from the Gulf of Cambay area. Since trace elements like Ti, Hf, Th, etc and Rare Earth Elements (REE) are immobile they preserve their signature without alteration and hence reflect primary petrogenic character. These 20 selected representative samples were analysed using ICP-Mass spectrometer. The rare earth element pattern normalized with shale are given in figure 14 & 15. The results of the analysis clearly reveal that there is one to one match between the archaeological material and Cambay bed sediments. This is characterized by leaching of light rare earth elements and a prominent Europeam anamoly .The ternary and Binary plots of both the materials show clustering of all samples in one place indicating the samples are of same host chemistry and are insitu i.e. that the archaeological material are not transported but are made from locally available material only.
Figure – 17
Figure – 18
Sampling : In order to substantiate the findings detailed sampling was carried out. Since the sea condition was very rough and the water turbid and brown, sampling was carried out in areas where side scan images show excellent results. The samples were collected by utilizing a grab sampler, dredger, gravity corer and vibro corer. Large numbers of samples were carefully collected, systematically numbered and properly preserved. The artifacts collected included a variety of pottery pieces, Mesolithic stone tools, a few Paleolithic macro stone tools, beads made of semiprecious stones, brick pieces, hearth material, wattle and daub structure materials, corals, perfectly holed stones,, fossilized human remains and human teeth. Fig.16 has three potsherd pieces. These are unfired and normally sun-dried, made of clay and of great antiquity. On the other side of the figure a cross like object and some figurines are seen. Fig.17 shows the shape of deer’s head and to the right a well turned ornamental piece with a straight hole in the center. How the ancients were able to make them in stone is still an enigma.
In Fig.18 there are four very important objects. First, one can observe a fossilized jaw bone (mandible) with a natural tooth kept in front. Next to it is a part of the carbonized wooden log. This was obtained from the top stratigraphic colomn at a depth about 30 to 40cm below the seabed and it was sent for dating. In the left corner there are rolled objects and long linear beads which when strung together forms a necklace. In the right hand bottom of the figure linear beads made of stone are there with holes in the middle.