However, many marine geologists are skeptical of the interpretations of the NIOT scientists. These Geologists argue that the many of the geometric patterns seen on the sonar images which the NIOT team interpreted to be submerged structures, are instead the inaccuracy of the sonar imaging process itself. Where underlain by lithified sediments and bedrocks, the linear patterns interpreted to be the foundations and walls of man-made structures might instead be naturally occurring orthogonal / rectilinear fracturing and jointing in the rock formations at the bottom of the Gulf of Khambhat. These Marine geologists argued that the sonar images are inconclusive and would remain open to various and contradictory interpretations, unless verified by actual underwater excavations. Without such physical investigations to clearly document the presence of artifacts in intact, stratified archaeological deposits and in situ man-made structures, whatever interpretations based on sonar imagery alone would remain unverifiable.
A round of further underwater explorations was made in the Gulf of Khambhat (Cambay) site by the NIOT team from 2003 to 2004, and the samples obtained of what was presumed to be pottery were sent to laboratories in Oxford, UK and Hanover, Germany, as well as several institutions within India, to be dated by Optically Stimulated Luminescence (OSL) and thermoluminescence dating techniques. These pieces returned dates ranging from 13000 ± 1950 BP up to the oldest at 31270 ± 2050 BP, leading to NIOT's chief geologist Badrinaryan Badrinaryan stating that they had uncovered the earliest-known pottery remains in the world, from about 31000 BP In his web publication of his findings, Badrinaryan (2006) stated:
Since some persons have expressed doubts about the pottery pieces, a thorough scientific study was made involving the pottery pieces to establish their authenticity. To determine the properties of various material including pottery, many samples were subjected to X-Ray Diffraction (XRD) analysis. Since the materials that constitute pottery etc are clays and heterogeneous mixtures of a variety of materials, these were accordingly analyzed. Every area has a special fingerprint pattern in the clay which can be recognized in X-Ray diffraction (XRD). The above analysis was carried out in Deccan College, Pune Maharashtra state, India, by using an advanced instrument which gave excellent results. The conclusions are that the pattern of pottery pieces corresponds very well with the locally available clay of Gulf of Khambhat (Cambay). The mineral patterns of habitational floor, wattle and daub and land materials (alluvial deposit) are comparable. The patterns of fired clay, floor brick piece, vitrified clay, compare very well. All these indicate that they are genuine artifacts, made from locally available material and are in situ. It fully confirms the presence of archaeological sites. The findings indicate that the pottery was produced locally with levigated clay, fired uniformly at about 700°C. From the presence of calcite in clays and pottery arid to semi-arid environmental conditions prior to the submergence of the site could be deduced. Alluvial deposits indicate the existence of ancient rivers which once flowed in the submerged regions of Gulf of Khambhat (Cambay).
However, the optically stimulated luminescence (OSL) dating of the items identified as pottery, which had the older OSL dates, produced dates that are almost identical to OSL dates obtained from associated sediments. That the pottery yielded OSL dates identical to associated sediments suggests that the pottery, which produced the older and oldest OSL dates, may never have been fired and actually consist of pieces of naturally cemented sediments. This raises the possibility that the extremely old samples, as argued for many other artifacts recovered from the Gulf of Khambhat (Cambay), are not man-made artifacts or potsherds, but rather geofacts and related objects of natural origin.
The XRD analysis does not prove that these artifacts are man-made as natural concretions can also form in local alluvial sediments. The XRD data only indicates that the extremely old samples consists of sediments, which came from the alluvial deposits underlying the currently submerged and typically buried floodplain somewhere along the length of the Gulf of Khambhat (Cambay). The calcite found in the extremely old pottery can be also interpreted to be the material cementing local alluvium together to form concretions, which have been misidentified as pottery. Such concretions are noted to be quite common in naturally occurring alluvial deposits.
Interpretations of the objects and seismic data differ sharply between archaeologists and lay commentators. The consensus among scientific archaeologists is that there is no evidence supporting claims of submerged Neolithic ruins and artifacts. In sharp contrast, amateur commentators, including Graham Hancock, Vedic mystics, and Hindu nationalists, argue that the evidence clearly indicates the presence of submerged Neolithic cities at the bottom of the Bay of Cambay.