The Wrangell Mountains, which form much of Wrangell-St. Elias National Park and Preserve, are made up largely of thousands of lava flows that have been erupted mostly from large broad volcanoes during the past 26 million years. This extensive volcanic terrain, which is called the Wrangell volcanic field, covers about 4,000 square miles — an area a little smaller than the State of Connecticut — and extends eastward from the Copper River Basin through the Wrangell Mountains, into the St. Elias Mountains of Alaska and the Yukon Territory of Canada.

The Wrangell volcanoes are among the highest mountains in North America and some of the largest (by volume) in the world. In comparison to most stratovolcanoes associated with convergent plate margins, such as along the Pacific"rim of fire", the Wrangell shield volcanoes are much more voluminous. Mt. Wrangell and Mt. Sanford, for example, each consist of about 250 cubic miles of lava. Compare that to about eight cubic miles for Mt. St. Helens and 47 cubic miles for Mt. Rainier, or even Mt. Fujiyama with 184 cubic miles.

All the volcanoes of the western Wrangell Mountains are less than 5 million years old with the youngest lava flows are possibly as recent as 50,000 years ago. Most of volcanoes of the Western Wrangell mountains are unlike other volcanoes located around the Pacific rim. Rather than erupting explosive lavas forming steep-sided cones, they have been built by the accumulation of hundreds of relatively fluid lava flows to form broad mountains with gentle slopes, typical of shield volcanoes. Now only youthful Mount Wrangell still displays a shield-like form; the other, generally older volcanoes have had much of their superstructure removed by glacial and other erosional processes.

More than 12 volcanic centers are known and mapped. Mounts Drum and Churchill have had explosive phases during their geologic changes.

Relatively recent eruptive activity has been noted in Mt. Wrangell in 1784, 1884-5, and 1900. On clear, cold, and calm days, steam plumes are often visible. Large volumes of ash were deposited 1,250 and 1,890 years ago from the eruption of Mt. Churchill (the White River Ash).

The principal basement rocks on which the Wrangell volcanoes erupted their great outpourings of lava are much older rocks and have had a complex geologic history. These rocks belong to what is referred to in the geologic literature as the Wrangellia terrane, which is part of an even larger group of exotic terranes — the Wrangellia composite terrane — that have been accreted to Alaska and the North American Continent during the past few hundred million years. On the basis of geophysical and fossil evidence, rocks of the Wrangellia terrane were formed in a tropical environment thousands of miles south of its present position. The Wrangellia terrane began as a volcanic arc about 300 million years ago, probably along the margin of an ancient North American Continent. As arc-related volcanic activity waned, a rift developed between the arc and continent, allowing the eruption of thousands of cubic miles of basalt lava flows that flooded and filled the rift-formed basin. Subsequently, shallow warm seas inundated the land, depositing layers of marine limestone and other sediment on the volcanic rocks.

During the next 200 million years, the Wrangellia terrane was gradually transported northward, where it was welded to other terranes and eventually docked against western North America about 100 million years ago. It now forms a belt extending from southern Alaska to southern British Columbia. Subsequently, other terranes, such as those composing the Southern Margin composite terrane, have been carried northward and accreted to continental Alaska. The last terrane to arrive — the Yakutat terrane — docked about 26 million years ago, concurrent with and partly responsible for the development of the Wrangell volcanic field.

The basement rocks upon which the Wrangell volcanoes erupted their great outpourings of lava are much older and have had a complex geologic history. These rocks, known as the Wrangellia composite terrane, were formed at a considerably lower, warmer latitude (17 degrees) thousands of miles south of its present position and about 300 million years ago.

Essentially, the mountain ranges of interior Alaska are the result of the collision and accretion of smaller, moving tectonic plates with the North American continent.

The Malaspina Glacier flows out of the St. Elias Range between Icy Bay and Yakutat Bay in a mass larger than the State of Rhode Island. It carries so much glacial silt that plants and trees take hold on its extremities, grow to maturity, and topple over the edge as the glacier melts. Flowing from the glaciers are a multitude of meandering rivers and braided streams. The Copper River the largest, forms the western boundary of the park starting in the Wrangells and emptying into the Gulf of Alaska in Chugach National Forest.

In the early 1900's the Kennecott Mining Co. transported copper from its mines near McCarthy by railroad along the Chitina and Copper rivers to ships at Cordova. Ore was extracted from these highly productive mines between 1911 and 1938 and lured many people to the area. During that period gold was extracted from the Nabesna area as well. Today mining still occurs on private lands within the park, and you can see evidence of earlier mining, including the ruins of the Kennecott mines, which have been placed on the National Register of Historic Places. Indian villages expanded and a number of new towns sprang up in mining's heyday. Copper Center, Chitina, Gulkana, and Chistochina are among the old Athapascin settlements. Yakutat, on the coast, is a traditional Tlingit fishing village.

Early History And Geologic Exploration

Ahtna Athabaskan natives traveled the river corridors, foothills, and passes of the Wrangell Mountains for several hundred years prior to European arrival in the area. They lived in semipermanent camps, leaving for weeks at a time to hunt and to gather berries, birch wood, and other resources. Trade routes with other native peoples were well established. Copper, found near the present-day town of McCarthy, was used for tools and for trade with other native groups. Rumors of the copper deposits, as well as the lure of fur animals, attracted Russians into the Copper River Basin for an extended period from the 1760's to 1867. Most encountered considerable hostility from the Ahtna, who fought the Russian occupation.

The first recorded geographic observations of the western Wrangell Mountains were made by Lt. Henry T. Allen of the U.S. Army in 1885. In March of that year, Allen and three companions landed at the mouth of the Copper River and began one of the most remarkable journeys in the history of Alaskan exploration. Mapping as they went, the party ascended the Copper River around the west end of the Wrangell Mountains, crossed the Alaska Range through Suslota Pass, and then proceeded down the Tetlin, Tanana, Koyukuk, and Yukon Rivers to the Bering Sea just in time to catch the last boat to leave the Alaska coast before freezeup in early September. Allen's party was the first scientific expedition to cross the Alaska Range from the Gulf of Alaska to the Yukon River.

Before going north over the Alaska Range divide into the Tanana River Valley, Allen explored the upper Copper River Basin, the Chitina River Valley, and the western Wrangell Mountains. He named the Chitina and the Chitistone Rivers (both names incorporating the Athabaskan word "chiti," meaning "copper") and established friendly relations with Chief Nicolai and his Copper River group of Ahtna Indians. He measured the heights and named many of the high Wrangell peaks, including Mount Blackburn, Mount Drum, and Mount Sanford, during his long summer sojourn in the area.

After Allen's exploration, several scientific parties explored the Wrangell Mountains area. The team of Lt. Frederick Schwatka of the U.S. Army and geologist C.W. Hayes of the U.S. Geological Survey reache d the Chitina River Valley by way of the White River and Skolai Pass in 1891.

Spurred by these early explorations and the influx of prospectors during the Klondike gold discoveries in Canada, the U.S. Geological Survey and the War Department notably increased their efforts to make topographic and geologic maps of the country. U.S. Geological Survey geologist F.C. Schrader accompanied the 1898 U.S. Army survey led by Capt. William Abercrombie up the Copper River and into the Wrangell Mountains. That same year, U.S. Geological Survey geologist W.C. Mendenhall joined U.S. Army Capt. Edwin Glenn's expedition from Cook Inlet up the Matanuska River into the Copper River Basin. Alfred Brooks and William Peters of the U.S. Geological Survey and Oscar Rohn and A.H. McNeer of the War Department conducted separate expeditions to the Nabesna and Chisana areas on the north side of the Wrangell Mountains in 1899.

These journeys eventually led to mineral development of the Wrangell Mountains. The first gold discovery in the northern Wrangell Mountains was on Jacksina Creek near the headwaters of the Nabesna River in 1899. In that same year, Oscar Rohn, on his exploration of the upper Chitina Valley, found rich pieces of chalcocite ore in the glacial moraine of Kennicott Glacier and pointed out similarities to the rich copper deposits of Michigan's Lake Superior District. Rohn also named the Chitistone Limestone and the Nikolai Greenstone, geologic formations that proved to be important hosts for mineral deposits. A year later, prospectors traced the chalcocite to deposits on Bonanza Ridge, which eventually became the incredibly rich Bonanza Mine, one of five mines that supplied copper and silver ore to the now-historic Kennecott Mill.

The Kennecott mines did not go into full production until 1911, when the completion of a 196-mi-long railroad from Cordova, near the mouth of the Copper River, to the Kennicott mining town allowed transport of the rich copper concentrate. In 27 years of operation, over a billion pounds of ore valued at $100 to 300 million was hauled on the railroad.

The mine and the railroad were abandoned in 1938, when the rich ore was exhausted. The railroad bed now provides the base for most of the Chitina-McCarthy Road along the south flank of the Wrangell Mountains in the heart of Wrangell-St. Elias National Park and Preserve.

Gold discoveries in the Nabesna area led to construction of the Nabesna Road, which was built in the early 1930's and used to haul gold ore from the now-closed Nabesna Mine. Today, the Nabesna Road provides vehicle

After the Kennecott mines closed, several efforts were made to revive mining interest in the area. Ernest Gruening, Director of U.S. Territories and later Alaska's governor and a U.S. Senator, was the first to recommend the area as a national park or monument. After a flight over the area in 1938, he wrote a memorandum to the Secretary of the Interior:

the region is superlative in its scenic beauty and measures up fully and beyond the requirements for its establishment as a National Monument and later as a National Park. It is my personal view that from the standpoint of scenic beauty, it is the finest region in Alaska . I have travelled through Switzerland extensively, have flown over the Andes, and am familiar with the Valley of Mexico and with other parts of Alaska. It is my unqualified view that this is the finest scenery that I have ever been privileged to see.

Passage of the Alaska Native Claims Settlement Act in 1971 authorized the Federal government to withdraw and study Federal lands in Alaska for future uses.In 1978, Present Jimmy Carter declared the area a National Monument because of its scientific and cultural significance. When Congress passed the Alaska National Interest Lands Conservation Act in 1980, the Wrangell Mountains became part of the 13.2 million acre Wrangell-St. Elias National Park and Preserve, the largest U.S. National Park.

Wrangell-St. Elias is one of four contiguous conservation units spanning some 24 million acres that have been recognized by the United Nations as an international World Heritage Site. The original 1978 designation included Wrangell-St. Elias and Kluane National Park in the Yukon Territory of Canada. In 1993, both Glacier Bay National Park and Preserve and a new park, the Alsek-Tatshenshini Provincial Park in British Columbia were added to that designation. Altogether, it is the largest internationally protected area in the world.

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