A Reconnaissance of Southern Andean Agricultural Terracing

Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: PHYSIOGRAPHY: CHAPTER II GEOGRAPHIC CONDITIONS The Physical Environment If a single word could conceivably cover the physiography of the area of terrace distribution, a simple mountainous would have to be the choice. The area of concern to this study is, because of the location of the terraces, defined in...
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Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: PHYSIOGRAPHY: CHAPTER II GEOGRAPHIC CONDITIONS The Physical Environment If a single word could conceivably cover the physiography of the area of terrace distribution, a simple mountainous would have to be the choice. The area of concern to this study is, because of the location of the terraces, defined in terms of mountains. The study area is essentially the southern margin of the Andean Altiplano, the west and the east flanks of the Andes in Northern Chile and Northwestern Argentina, respectively. Most of the terraced sites are valley slopes within the great rough dissected zones flanking the high Puna, that high altitude desert which dominates Bolivia and extends into Argentina and Chile south to about 27. The eastern and the western margins of this mountain mass differ in several details. Western Andean Slopes The country of Chile is all a lengthy prelude to the Andes. The land is dominated by the mountains, especially in the far north. There, the mountain crest is really the massive edging of a series of great lavas and deep beds of welded tuffs. Atop and east of this topographic rim are heaped more recent volcanic cones, some reaching to 6,000 m. The core of the Andes, taken at northernmost Chile, is at its widest. On maps it is a plateau landscape, but from within it is a gigantic basin and range series, a high altitude desert. Between the outer rim of the altiplano and the sea, the western slopes are deeply incised by canyons, steep of gradient, clogged with debris, and known to rage torrents in summer thundershower flood. Normally there is but a spare trickle of surface flow in main branches. At elevations above 2,000 m., generally, streams have cut the volcanic rim into large first order drainage basins. Below 2,000 m. there normally are broad surf...