Thursday, November 3, 2016

ATITLAN & TOLIMAN VOLCANOS BY ARTHUR P. COLEMAN (1852-1939)




ARTHUR P. COLEMAN (1852-1939)
  Atitlбn (3,535 m -11,598ft) & Tolimбn  (3,158 m -10,361ft) 
Guatemala 

In Atitlan and Tolimon seen from Lake Atitlan, 1937, watercolor, 

The mountains
Atitlбn volcano  (3,535 m - 11,598 ft)  is a large, conical, active stratovolcano adjacent to the caldera of Lake Atitlбn in the Guatemalan Highlands of the Sierra Madre de Chiapas range. It is within the Sololб Department, northern Guatemala. The volcano has been quite active historically, with more than a dozen eruptions recorded between 1469 and 1853, the date of its most recent eruption. Atitlбn is part of the Central American Volcanic Arc. The arc is a chain of volcanoes stretching along Central America formed by subduction of the Cocos Plate underneath the Caribbean Plate. This volcano is part of the Ring of Fire around the Pacific Ocean. Atitlбn is home to two particularly rare and beautiful birds that are endemic to the cloud forests of this region. The horned guan (Oreophasis derbianus) is a Pleistocene relic of the Cracidae family that persists today only in small fragments of its previous range. Its habitat is limited to cloud forests above approximately 1,650 metres (5,410 ft). This bird is the size of a turkey and the adult male has a one-inch scarlet-colored "horn" projecting straight up from the top of its head. The Cabanis's or azure-rumped tanager (Tangara cabanisi) is probably the most restricted-range species in the region. It occurs only at mid-elevations within the Sierra Madre del Sur of Chiapas, Mexico and western Guatemala. Atitlбn lies on the southern rim of the caldera, while Volcano San Pedro and Volcano Tolimбn lie within the caldera. San Pedro is the oldest of the three and seems to have stopped erupting about 40,000 years ago. Tolimбn began growing after San Pedro stopped erupting, and probably remains active, although it has not erupted in historic times. Atitlбn has developed almost entirely in the last 10,000 years and remains active, with its most recent eruption having occurred in 1853.
Tolimбn volcano  (3,158 m -10,361 ft) is located on the southern shores of Lago de Atitlбn. The volcano  was formed near the southern margin of the Pleistocene Atitlбn III caldera. The top of the volcano has a shallow crater and its flanks are covered with the thick remains of ancient lava flows that emerged from vents in the volcano's flanks. A parasitic lava dome, known as Cerro de Oro, was formed on the volcano's northern flank, which may have erupted a few thousand years ago.
San Pedro volcano  (3,020m -9,908 ft) (also named Las Yeguas) represented in the foggy background of in the Coleman painting, is the third stratovolcano on the shores of Lago de Atitlбn, in the Solol Department of northern Guatemala. At its base is the village of San Pedro La Laguna.
The first volcanic activity in the region occurred about 11 million years ago, and since then the region has seen four separate episodes of volcanic growth and caldera collapse, the most recent of which began about 1.8 million years ago and culminated in the formation of the present caldera. The lake now fills a large part of the caldera, reaching depths of up to 600 metres.
The caldera-forming eruption is known as Los Chocoyos eruption and ejected up to 300 km3 (72 cu mi) of tephra. The enormous eruption dispersed ash over an area of some 6 million kmІ: it has been detected from Florida to Ecuador, and can be used as a stratigraphic marker in both the Pacific and Atlantic oceans (known as Y-8 ash in marine deposits). A chocoyo is a type of bird which is often found nesting in the relatively soft ash layer.
On February 4, 1976, a massive earthquake (magnitude 7.5) struck Guatemala, killing more than 26,000 people. The earthquake fractured the lake bed and caused subsurface drainage from the lake, allowing the water level to drop two meters within one month

The artist 
Arthur Philemon Coleman was a Canadian a geologist, professor, minerals prospector, artist, Rockies explorer, backwoods canoeist, world traveller, scientist, popular lecturer, museum administrator, memoirist and...  one of Canada’s most beloved scientist. 
Arthur Coleman is a fine example of that rare bird, a polished amateur artist whose drawings and paintings stand comfortably beside those of many professionals. He was active during the time when sketching and painting was ceding to photography the task of recording the visible world. Although he was also a photographer, painting was, for him, both a poetic and a descriptive pursuit, a way of wrapping an artistic expression around a phenomenon he was interested in or moved by. Thus motivated, Coleman's paintings give much joy and command a good deal of respect. The more surprising, perhaps given that he used to introduced himself more as a geologist than a painter.
Coleman travelled throughout the United States for professional conferences as well as geological field work.  He visited many of the major American mountain ranges including: the American Cordillera Mountains (Washington, Oregon and California); the Sierra Nevada Mountains (California and Nevada); Yellowstone National Park (Wyoming, Montana and Idaho); and the Appalachian Mountains (eastern United States). Pleistocene glaciation had extended in Northern Europe as far south as Berlin and London and covered an area of two million square miles. Coleman also visited such countries as India, Australia, Brazil, Argentina, Scandinavia, Bolivia, New Zealand, South Africa and Uruguay. In his final years he made two expeditions to the Andes in Colombia, to mountains in Southern Mexico and to two mountains in Central America.  He achieved the first ascent of Castle Mountain in 1884, and in 1907, he was the first white man to attempt to climb Mount Robson. He made a total of eight exploratory trips to the Canadian Rockies, wholly four of them looking for the mythical giants of Hooker and Brown. 
From 1901 to 1922, he was a Professor of Geology at the University of Toronto and was Dean of the Faculty of Arts from 1919 to 1922. From 1931 to 1934, he was a geologist with the Department of Mines of the Government of Ontario. He was elected a Fellow of the Royal Society of Canada in 1900 and was its President in 1921. In 1929, he was appointed Honorary Vice-President of the Royal Canadian Geographical Society.
 "Mount Coleman" and "Coleman Glacier" in Banff National Park is named in his honor.  He was awarded the Penrose Medal in 1936.
He planned to climb "hi" mountain, "Mount Coleman"'in the Albertan Rockies, and had also prepared a trip to British Guiana, but death intervened.
He was author of:
- Reports on the Economic Geology of Ontario (1903)
- Lake Ojibway; Last of the Great Glacial Lakes (1909) 
- The Canadian Rockies: New and Old Trails (1911)
- Ice Ages, Recent and Ancient (1926), and was co-author of Elementary Geology (1922).
- The Last Million Years (1941) edited by George F. Kay