Abyssinia Once Studded in Ice Mounds

Manawatu Times, Volume 66, Issue 115, 16 May 1941, Page 3

Abyssinia Once Studded in Ice Mounds

STOCKHOLM. A great mauy interesting observations regarding the natural conditions during the glacial age in Kenya and Abyssinia are contained in a report by the Swedish scientist, Dr. Erik Nilsson, published in the latest number of the Swedish Geographical Journal. Dr. Nilsson, who is a disciple of the great Swedish geologist, Gerard de Geer, has studied conditions in those regions for several years. During his first expedition of 1927-28 ho mapped out the glacial-geological conditions of Mt. Elgon, Kilimanjaro, Mt. Kenya and other equatorial volcanic mountaiu tops, and under the protection of the Emperor of Abyssinia he had an opportunity to investigate the inaccessible Semia mountains very thoroughly during his second expedition in 1932-33. The most sensational result from these investigations is Dr. Nilsson’s conclusion that the highest parts of Abyssinia have also been covered by ice, which overthrows certain generally accepted theories concerning the climatic mechanism of the ice age in Equatorial Africa. Mountain Peaks Worn The glacier areas -in Equatorial Africa were both very much larger and more numerous during the ice age than at present, but they were confined to the very high mountain tops also then. While, however, at present only mountains of over 5000 metres havo snow caps, the “ small mountains” of 4000 metres and lower also came up to the snow-line during that time. This has been determined by the very detailed maps prepared by Nilsson of the traces left by the ice hood on seven mountain slopes in the regions investigated. Although the ice-covered areas wero comparatively unimportant, these sections of the earth were quite as materially changed in their fundamental features as the great ice regions. Tho severe winter climate of Africa did not, however, constitute an ice age, being no glacial, but rather a pluvial period. Where there are now desert depressions without any outlet—possibly with a salt water lake here and there in the lowest parts—thero were concurrently with tho ice age of the north largo expanses of deep freshwater lakes, fed by the abundant rainfall. The warm periods that intervened between our own ice periods, however, caused these lakes to dry up. The changes in tho water level of these “pluvial” lakes provide tho clearest record of the changes in the climate, represented in other regions by changes from periods of excessive heat to ice periods, and vice versa. The main task of Dr. Nilsson, was to obtain a grasp of tho course of development in the geological lakes of the region and compare this development with liis conclusions from a study of tho ice hoods of the mountain tops. Shipping Lake Levels These delajls of tho geological developments which have reduced enormous expanses of water to small lake remnants in Kenya and Abyssinia are contained in the report. Clear evidence is provided by the deposits on the shore lines to prove that the lake levels have repeatedly risen and fallen and tins has occurred iu rhythm with tho swelling and contraction of the glaciers on mountains in tho proximity. In Nilsson’s time schedule are also included the aftermath of the upheavals in the earth’s crust which created the Rift. Valley and the Red sea, and even finds related to far-away stone age cultures to have been fixed. In a critical and convincing manner Dr. Nilsson compares his results from British East Africa and Abyssinia with corresponding researches in Egypt and Northern Europe. The same climatic oscillations have taken place in Africa as in northern Germany and Scandin-

avia. There these changes could merely produce minor advances and retrogressions in the edge of the land ice. In the equatorial belt of Africa, on the other hand, it led to the disappearance and fresh formation of tlio mountain ice hoods, and in the filling and dryingup of the desert lakes. Dr. Nilsson expresses the hope that he will bo put in position to conclude his work in the regions concerned with an investigation of the geological history of the Jordan Valley. In the Dead Sea basin the problems of the pluvial age are gathered as in a nutshell.