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KARACHI: Scientists studying the water and sediment samples collected from the one-square-kilometre island that emerged off the Makran coast last year has found well-preserved shells of certain marine organisms that are known to survive on sulphur and methane.
The island located at a distance of two kilometres from the Makran coast near the point where the Hingol River drains into the sea is reported to have been collapsed due to strong currents and winds in a similar way as happened in the case of the island that emerged in the same area in 1999.
The recent appearance of the island was looked at as the re-emergence of the past island — Malan.
The finding, according to the scientists, provides scientific evidence to the widely held belief that the specific area has marine reserves of methane gas.
“This is the first time that we have found rocks and boulders with burrows and holes that indicates the forceful eruption of the mass. Also, the presence of huge rocks on the island led us to assume that this time the island had emerged with greater pressure, though we are not sure about the exact depth from where the mass has erupted,” said Dr A.R. Tabrez, the director general of the National Institute of Oceanography (NIO) where the samples were analysed for dissolved oxygen, salinity, elemental composition, mineralogical composition and textural analyses.
Other findings of the samples’ testing showed dominant presence of clay minerals such as muscovite and chlorite with quartz and calcite. The elemental composition of the sediments was dominated by silicates, aluminium, calcium and iron.“The shells are probably of the calyptogena species, which is known to survive on sulphur and methane. A strong correlation was found between the sediments of the offshore island and the onshore mud volcanoes,” said Dr Asif Inam, the director continental shelf project at the NIO.
According to Dr Inam, the analysis of the gas sample taken from the water column of the offshore Malan Island showed that it contained methane, ethane, propane and butane.
All data pointed to the presence of microbiologically generated bacterial methane, excluding thermogenic gas.
According to the scientists, the Makran coastal belt is reported to have extensive reserves of frozen methane that exist in the form of gas hydrates (crystalline water-based solids physically resembling ice which were formed under conditions of relatively high pressures and low temperatures) hundreds of metres below the sea floor. And whenever this highly pressured gas finds a weak space to release some of its energy, a dome-like structure (island) is created within the waters or it emerges on the sea surface.
“The space to release energy could be formed due to tectonic movements, creating some fractures and fissures in the strata. Sometimes, the structures do not come out of the water and so go unnoticed,” said Dr Inam.
Explaining the topography of the area, Dr Inam said that it was an active seismic region where three tectonic plates — Indian, Eurasian and Arabian — were converging. “The area is required to be mapped in detail to ascertain the potentially hazardous parts. Besides, the area could be explored to overcome the energy crisis.”
Explaining the significance of gas hydrates, Moin Raza Khan, the general manager (exploration) of the Pakistan Petroleum Limited (PPL), said the amount of natural gas in gas hydrate worldwide was estimated to be far greater than the entire world's conventional natural gas resources.
“This is what makes the gas hydrates a potential energy resource for the future. It is believed to contain more organic carbon than the world's coal, oil, and conventional natural gas, together. The diminishing fossil fuels and energy security concerns have made scientific communities work on gas hydrate as a potential energy resource,” he said.
According to the PPL official, there was a need for research organisations like the NIO coming together with organisations involved in the exploration of oil and gas internationally and locally to explore the potential of marine gas reserves.
“Relevant technology for exploration is expensive and not being used for commercial purposes in the world. India, however, is working extensively in the exploration of gas hydrates,” he said.
