GEOLOGIST SEEKING DUNITE, GREENSTONES

Press, Volume C, Issue 29702, 21 December 1961, Page 14

GEOLOGIST SEEKING DUNITE, GREENSTONES

An American geologist. Dr. R. G. Coleman, has arrived in New Zealand with the examination of the Dun Mountain deposits of Nelson as one of his main objectives. He has been sent by the United States Geological Survey under the American Civil Service Employees’ Training Act, and will study serpentine and related rocks, including the dunite of Dun Mountain and the greenstones of the West Coast and other places. Dr. Coleman will also observe the methods of the New Zealand Geological Survey, and will operate mainly from the survey's headquarters in Lower Hutt, although he will work closely too at one stage with the Christchurch district geologist. Mr H. S. Gair. In the south he will co-operate with Professor D S. Coombs of the University of Otago. The dunites and serpentines —serpentines were hydrated dunites—were believed by most geologists to derive from the earth's mantle, below the crust of sedimentary and igneous rocks, said Dr Coleman. The study of serpentines. therefore, might give some idea of conditions deep in the earth. This was true also of the rocks found as inclusion in the serpentine group and nowhere else, and which seemed to have been metamorphosed by them in situ or brought to the surface with them. New /••land was one of the best areas of ihe world to examine serpentines because "'ey were s~a?tered through many different geological environments

to the South Island, the 7/,fMend from IwUnd, through the ’>.*2 »'*» to the ■ Hills of the upper s»K»u There are others in

the Livingstone Range of Southland and the Olivine Range of the extreme south of Westland. In the North Island there are outcrops at Piopio (South Auckland). Silverdale (Auckland), and North Cape, although the Piopio and Silverdale serpentines have been practically mined out as a fertiliser carrier.tor aerial topdressing Dr. Coleman, who will be in the country until next December. expects to visit all these areas except the Olivine Range, which is too remote He also hopes to search for greenstone in the creeks of South Westland. “Smart” Maoris The Maoris* discovery of the properties of greenstone and particularly its hardness, showed how smart they were said Dr. Coleman. The greenstones were closely related to other jades and nephrites, which as a group had been widely used for tool-making by stone-age peoples The native Indian.of California, where he lived however, had not discovered their local jades, which had been unrecognised until his department had picked them up in 1952. (Dr. Coleman is stationed at the western headquarters of the Geological Survey at Menlo Pa Z“- near San Francisco.) pie Dun Mountain of veison was a famous locality among geologists the world . r>r Goleman said. It was -h e type of locality for bv Hoch about inn years ago Nearbv ,n -he Ro-i ine v,Hei was the type for rndtnmte a kind of e3rT , e t He planned m spend about six weeks manning j n the Dun Mountain area ~T he sernentines provided the world supply of chromite while copper, nickel, and

asbestos, too. had seen mined from them, he added. Dunite was used as moulding sand and olivine in alloying Whether mining was economic m any particular de nosit. however, depended on a variety of things, not leasi the market Turkey was the biggest exporter of chrome from chromite, for example, and competition would probably be difficult as things! were now. but the position' could change.