Temperature Gradient in the Earth's Crust

Abstract

SOME observations on temperatures in a deep bore hole in South Africa were described by L. J. Krige and H. Pirow in June last before the Geological Society of South Africa. The bore-hole, which had been made in search of oil, is situated on the Dubbeldevlei Farm, near Carnarvon, at an elevation of about 3250 feet above sea-level. The country is flat and underlain by nearly horizontal strata assigned to the Ecca, Dwyka, and Fish River series. These rest upon granite and gneiss at a depth of 2687 feet. The borehole had been carried to a depth of 5080 feet, but the lower 160 feet had become silted up. The observations on temperature ranged from the surface down to a depth of 4912 feet, and were successfully made at 26 levels. Water stands in the hole at 32 feet from the surface. The upper noo feet of the hole is lined with 3-inch casing. From noo feet to 3000 feet the diameter of the hole is 2ff inches; it is then i\ inches to 4500 feet, and 2rV inches from that point to the bottom.