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Juneau Gold Belt
The Juneau gold belt is located in the southeastern portion of the U.S. state of Alaska. This belt is approximately in length, north/northwest-trending, and extends from Berners Bay southeastward to Windham Bay, southeast of Juneau, and includes Douglas Island. The belt contains over 200 gold-quartz-vein deposits with production nearing of gold. More than three-quarters of Alaska's lode gold was mined from the Juneau gold belt. History Gold mining in the belt became active after an 1869 study of the Juneau mining district, of which the Juneau gold belt is but one part. Chief Kowee was one of the earliest gold prospectors in the belt area. In 1880, he revealed to prospectors Joe Juneau and Richard Harris the presence of gold in Silver Bow Basin's Gold Creek, after which Juneau was founded in the same year. The Juneau gold rush of 1880 resulted in some of the largest gold mines in the world, including the Treadwell complex of lode mines on Douglas Island and the Alaska-June ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Territory Of Alaska
The Territory of Alaska or Alaska Territory was an organized incorporated territory of the United States from August 24, 1912, until Alaska was granted statehood on January 3, 1959. The territory was previously Russian America, 1784–1867; the Department of Alaska, 1867–1884; and the District of Alaska, 1884–1912. Origin Passage of the 1899 Criminal Code which, among other things, included a tax on liquor, led to increased calls for Alaskan representation in Congress, and the debate finally ended on August 24, 1912, when the Alaska District became an organized, incorporated territory of the United States. The ''Second Organic Act'' of 1912 renamed the District the Territory of Alaska. By 1916, its population was about 58,000. James Wickersham, a Delegate to Congress, introduced Alaska's first statehood bill, but it failed for lack of interest from Alaskans. Even President Warren G. Harding's unprecedented visit in 1923 (just days before his death) could not create wides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrane
In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its own distinctive geologic history, which is different from that of the surrounding areas—hence the term "exotic" terrane. The suture zone between a terrane and the crust it attaches to is usually identifiable as a fault. A sedimentary deposit that buries the contact of the terrane with adjacent rock is called an overlap formation. An igneous intrusion that has intruded and obscured the contact of a terrane with adjacent rock is called a stitching pluton. Older usage of ''terrane'' simply described a series of related rock formations or an area having a preponderance of a particular rock or rock groups. Overview A tectonostratigraphic terrane is not necessarily an independent microplate in origin, since it may not contain the full thickness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion (geology)
Accretion, in geology, is a process by which material is added to a tectonic plate at a subduction zone, frequently on the edge of existing continental landmasses. The added material may be sediment, volcanic arcs, seamounts, oceanic crust or other igneous features. Description Accretion involves the addition of material to a tectonic plate via subduction, the process by which one plate is forced under the other when two plates collide. The plate which is being forced down, the subducted plate, is pushed against the upper, over-riding plate. Sediment on the ocean floor of the subducting plate is often scraped off as the plate descends. This accumulated material is called an accretionary wedge (or accretionary prism), which is pushed against and attaches to the upper plate. In addition to accumulated ocean sediments, volcanic island arcs or seamounts present on the subducting plate may be amalgamated onto existing continental crust on the upper plate, increasing the continental ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynn Canal
Lynn Canal is an inlet (not an artificial canal) into the mainland of southeast Alaska. Lynn Canal runs about from the inlets of the Chilkat River south to Chatham Strait and Stephens Passage. At over in depth, Lynn Canal is the deepest fjord in North America (outside Greenland) and one of the deepest and longest in the world. The northern portion of the canal braids into the respective Chilkat, Chilkoot, and Taiya Inlets. Lynn Canal was explored by Joseph Whidbey in 1794 and named by George Vancouver for his birthplace, King's Lynn, Norfolk, England. Lynn Canal was frequently visited by maritime fur traders from at least 1800. The '' Atahualpa'' visited in 1801 and its log mentions an earlier trading visit by an unidentified ship. In April 1811 the American maritime fur trader Samuel Hill Samuel Hill (13 May 1857 – 26 February 1931), usually known as Sam Hill, was an American businessman, lawyer, railroad executive, and advocate of good roads. He su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastineau Channel
Gastineau Channel (Lingít: ''Séet Ká'') is a channel between the mainland of the U.S. state of Alaska and Douglas Island in the Alexander Archipelago of southeastern Alaska. It separates Juneau on the mainland side from Douglas (now part of Juneau), on Douglas Island. The first European to sight the channel was Joseph Whidbey early in August 1794, first from the south and later from the west. It was probably named for John Gastineau, an English civil engineer and surveyor. Characteristics The channel is navigable by large ships, only from the southeast, as far as the Douglas Bridge, approximately . Between the bridge and Juneau International Airport, approximately , it is navigable only by smaller craft and only at high tide. The channel is becoming increasingly unnavigable due to shallow water depths. The two principal causes for this are: # Isostatic rebound Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coast Mountains
The Coast Mountains (french: La chaîne Côtière) are a major mountain range in the Pacific Coast Ranges of western North America, extending from southwestern Yukon through the Alaska Panhandle and virtually all of the Coast of British Columbia south to the Fraser River. The mountain range's name derives from its proximity to the sea coast, and it is often referred to as the Coast Range. The range includes volcanic and non-volcanic mountains and the extensive ice fields of the Pacific and Boundary Ranges, and the northern end of the volcanic system known as the Cascade Volcanoes. The Coast Mountains are part of a larger mountain system called the Pacific Coast Ranges or the Pacific Mountain System, which includes the Cascade Range, the Insular Mountains, the Olympic Mountains, the Oregon Coast Range, the California Coast Ranges, the Saint Elias Mountains and the Chugach Mountains. The Coast Mountains are also part of the American Cordilleraa Spanish term for an extensive chain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmon Creek Dam
The Salmon Creek Dam is a concrete arch dam on the Salmon Creek, northwest of Juneau, Alaska. Built in 1914, it is the world's first constant-angle arch variable radius dam. Since it was built, over 100 such dams have been constructed all over the world. The dam was designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers in 2022. The dam was built by the Alaska-Gastineau Mining Company to meet the electrical energy needs for mining operations. The dam continues to be fully functional for hydroelectric generation, as one of the drinking water sources to Juneau city and for aquaculture and fishing. When built, adoption of the constant arch design for the dam reduced costs by 20% because less concrete was needed to construct the dam. Of the two hydroelectric power stations built at the initial stage (one at the upper level and the other at the lower level) – the latter one is still in use after a new powerhouse was built adjoining t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Bureau Of Mines
For most of the 20th century, the United States Bureau of Mines (USBM) was the primary United States government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources. The Bureau was abolished in 1996. Summary USBM was established in the Department of the Interior on May 16, 1910, pursuant to the Organic Act (Public Law 179), to deal with a wave of catastrophic mine disasters. The Bureau's mission was gradually expanded to include: * The conduct of research to enhance the safety, health, and environmental impact of mining and processing of minerals and materials. * The collection, analysis, and dissemination of information about mining and processing of more than 100 mineral commodities across the Nation and in more than 185 countries around the world. * Analysis of the impact of proposed mineral-related laws and regulations upon the national interest. * Production, conservation, sale, and di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Economic Geology
Economic geology is concerned with earth materials that can be used for economic and/or industrial purposes. These materials include precious and base metals, nonmetallic minerals and construction-grade stone. Economic geology is a subdiscipline of the geosciences; according to Lindgren (1933) it is “the application of geology”. Today, it may be called the scientific study of the Earth's sources of mineral raw materials and the practical application of the acquired knowledge. The term commonly refers to metallic mineral deposits and mineral resources. The techniques employed by other earth science disciplines (such as geochemistry, mineralogy, geophysics, petrology, paleontology and structural geology) might all be used to understand, describe, and exploit an ore deposit. Economic geology is studied and practiced by geologists. Economic geology may be of interest to other professions such as engineers, environmental scientists, and conservationists because of the far-reachi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Admiralty Island
Admiralty Island is an island in the Alexander Archipelago in Southeast Alaska, at . It is long and wide with an area of , making it the seventh-largest island in the United States and the 132nd largest island in the world. It is one of the ABC islands in Alaska. The island is nearly cut in two by the Seymour Canal; to its east is the long, narrow Glass Peninsula. Most of Admiralty Island—955,747 acres (3,868 km2)—is protected as the Admiralty Island National Monument administered by the Tongass National Forest. The Kootznoowoo Wilderness encompasses vast stands of old-growth temperate rainforest. These forests provide some of the best habitat available to species such as brown bears, bald eagles, and Sitka black-tailed deer. Angoon, a traditional Tlingit community home to 572 people, is the only settlement on the island, although an unpopulated section of the city of Juneau comprises (6.2 percent) of the island's land area near its northern end. The island's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by total area. Its southern and western border with the United States, stretching , is the world's longest binational land border. Canada's capital is Ottawa, and its three largest metropolitan areas are Toronto, Montreal, and Vancouver. Indigenous peoples have continuously inhabited what is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts, France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation, Canada was formed as a federal dominion of four provinces. This began an accretion of provinces an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
