Gifts and Perils of Landslides
Catastrophic rockslides and related landscape developments are an integral part of human settlement along upper Indus streams
Ghoro Cho: Two Landslide Stories
Ghoro Cho (“heap of great stones”) comprises a series of boulder-covered ridges across the floor of Shigar Valley (see Figures 6 and 8). Early in my investigations, I stayed there in the shepherds’ hut at Kor-Kor-Tsok-Boo. One evening, having heard of my interest, Apo (grandfather) Haji Ali elected to tell me the “real” story of the great stones. It was after supper and we sat around the open fire, the animals milked and settling down in the corrals, Haji Ali’s face alternately lit by the flames or obscured by the smoke.
Long ago, he said, where Ghoro Cho now lies there was a great and prosperous city. A traveling holy man came there and asked the ruler, the Rajah, for food and shelter. He was turned away, and by other wealthy folk. At last a poor woman gave him shelter and shared her food. Next morning he told her to climb to some springs high above the valley floor. He went to the opposite side and smote the rock with his staff. A great part of the mountain came down, burying the city, its wealth and pride.
Haji Ali’s story resembles morality tales about disasters in many places, including other Karakoram landslides. It may seem more myth than fact. Yet the details are singular, and whoever crafted the story was a fair geologist or landscape detective. Next morning the storyteller walked with me, pointing out the huge scar on the mountain side struck by holy man. Opposite, he identified Mango village and its springs where the old woman remained safe above the cataclysm. He showed me many features among the boulders of Ghoro Cho that proved valuable in reconstructing its geological as well as human story. Visiting the scar on the mountain side, I found green crystalline bedrock identical to Ghoro Cho boulders. Just 100 meters below Mango village, I found the outermost boulders and tell-tale greenish deposits marking the landslide rim.
However, this is also important in relation to another story—one from modern geoscience. For over a century Ghoro Cho was interpreted by earth scientists as moraine: debris dumped by glaciers during the Ice Age. I had passed it many times assuming the ridges were moraines, an easy mistake to make. But Haji Ali had the answer to definitively separate landslides from moraines—through rock type. The boulders and other visible fragments of Ghoro Cho are 100 percent that green crystalline rock of the source slope. Major mineral and major element analyses of samples showed that even the finest dust is of identical composition. Glaciers had indeed flowed into the valley, but carried quite different rock types, and of great variety—much as the rivers do today. Meanwhile, rock avalanche particles, from smallest to largest, have the tell-tale angular or “chink stone” character of fractured and crushed material. Moraines of large glaciers have diverse particle shapes including stones rounded in meltwater streams.
Of course, rock type analysis is bread-and-butter for any trained geoscientist, particle shape for the sedimentologist, but in this case, no one thought it necessary to check them out. The most influential studies from the 1850s to the 1980s offered compelling interpretations of Ghoro Cho as glacial. Indeed, Quaternary geologists believed these and some other landslide deposits represented the same three or four Ice Age glaciations described around the European Alps and in Scandinavia. The author of Haji Ali’s story knew better, but the moraine hypothesis prevailed until the 1990s.
Ghoro Cho can be a formidable place, dark and forbidding from a distance, mostly barren and swept daily by dust storms. Yet, every square inch is known to local people. Too far from water for cultivation, the area serves mainly as grazing land. Troglodyte homes for shepherd families and their animals lie under the largest boulders, and the residents have names for every feature. Many other stories are told, recalling the wolves, bears and Siberian tigers that once sought refuge among the boulders; dangerous djinns or “fairies”; and heroes from the Kesar Saga, the great oral epic of Shigar valley. Among these narratives are solid grains of empirical and practical truth, useful as environmental knowledge or contributing to a sense of place, history and calamity.
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