New Geological Map Series

Press, Volume CIII, Issue 30428, 30 April 1964, Page 7

New Geological Map Series

The area covered in the new Hurunui sheet of the 4in to-a-mile geological map series of the Geological Survey, Department of Scientific and Industrial Research, “is tectonically active and severe earthquakes can be expected,”, says Mr D. R. Gregg, of the Christchurch office of the survey, in his notes which accompany the sheet. “Three major destructive earthquakes have occurred in the century since European settlement: that of 1888 accompanied by up to Bft of horizontal movement on the Hope fault; the Cheviot earthquake of 1901; and the Arthur’s Pass earthquake of 1929, the epicentre of which was near , the Hope fault,” Mr Gregg says. The sheet covers an area from Bell Hill in the northwest to the Hutt Range in the south-west, thence to the sea at North New Brighton, and up the coast to Oaro. it includes four main landscape types. In the north-west corner is a small part of Westland, composed of ancient rocks with some later cover; next are the Alpine mountain ranges of folded and fractured rocks of Mezozoic age (about 60 million to 180 million years ago); then there is range-and-basin terrain of similar but less altered rock forming, the foothills; and, finally, alluvial outwash fans which form the northern extension of the Canterbury Plains. This sheet marks the way stage in the survey’s publication of similar maps to cover the whole country. The compilation of the remaining 14 sheets is well advanced,, and it is hoped the series will be completed in 1966. Sheet No. 15, Buller; is expected to

appear soon. Each sheet represents the work of many officers of the department, usually in a particular district office; the Hurunui sheet was produced in Christchurch. Describing the economic geology of the area, Mr Gregg mentions ground-water, (including hot springs), limestone, coal, sand and clay (including bentonite), gravel, building stone, gold, talc, and oil prospects.