Geologists delve into rock history in southeast Alaska (2023)

FAQs

What is the geology of southeastern Alaska? ›

Southeastern Alaska is underlain by Quaternary surficial deposits and by sedimentary, volcanic, intrusive, and metamorphic rocks ranging in age from Quaternary to Proterozoic(?).

Most of Alaska's oldest rocks are approximately one billion years old, although Alaska's oldest known rock is about two billion years old. New earth materials are born from volcanoes, such as along the Aleutian Arc, recycled into sediments from weathering processes, and lithified from sediments into new rock.

The dominant rocks in the sequence are interbedded andesitic tuff breccia, volcanic graywacke, and siltstone and argillite; less common rocks include coarse volcanic conglomerate, possibly broken pillow breccia, and dark blue-gray marble.

The Iditarod rocks are more than 2 billion years old. This is remarkable because most rocks in Alaska formed 500 million years ago or even more recently. Earth formed about 4.5 billion years ago.

Southeast Alaska includes over 1,100 islands, which are the tops of the partly submerged coastal mountain range. The region is bounded to the east by a mainland mountain range with peaks reaching 10,000 feet (3,048 m) in elevation. These mountains and associated icefields are bisected by several large glacial rivers.

Most of the bedrock of Southcentral Alaska originated as marine sediments that were uplifted when terranes accreted onto the continent. Granite plutons have been exposed in the Talkeetna Mountains, Prince William Sound and in the Alaska Range.

Devonian rocks are widespread in southeastern Alaska. eastern Alaska consist of basalt, andesite, tuff, limestone, sandstone, slate, and conglomerate.

Alaska doesn't have a state rock, but it does have a state gem, jade. A gem is a precious or semiprecious rock or mineral that looks pretty when it is cut and polished. Jade is usually green, and it is hard but easily carved. Most of the jade in Alaska is found on the Seward Peninsula.

Geologist Tom Bundtzen uses a binocular microscope to look at one of the oldest rocks in Alaska, which formed more than 2 billion years ago and was found near Iditarod. Geologist Marti Miller with a 2-billion-year-old rock she collected near Iditarod.

Is it illegal to take rocks from Alaska? ›

You are prohibited from taking rocks, flowers, plants, fossils, horns, antlers, bones, and historical artifacts from Alaska State Parks. 11 AAC 12.170 (Disturbance of Natural Objects) prohibits removal or disturbance of natural objects.

The Alexander Archipelago (Russian: Архипелаг Александра) is a 300-mile (480 km) long archipelago (group of islands) in North America lying off the southeastern coast of Alaska. It contains about 1,100 islands, the tops of submerged coastal mountains that rise steeply from the Pacific Ocean.

The Glacier Ice™ Gemstone with its deep blue coloration is reminiscent of Alaska's glaciers. Glacier Ice™ is a special variety of natural Blue Zircon available ONLY at Alaska Jewelry. Glaciers form when snow falls, accumulates, and does not melt.

The oldest intact rock found on Earth to date is from the Acasta Gneiss Complex of northwest Canada. U/Pb dates of zircon from the gneiss reach into the Hadean Eon at 4.02 Ga.

Rhodonite

Rhodonite is a manganese silicate mineral known for its light-red or dark-pink hue.

The states in the upper part of the region have rolling hills, rich river valleys and high flat areas called plateaus. The states in the lower part of the region have beaches, swamps, and wetlands. The Appalachian Mountains cover most of the upper part of the Southeast region.

Southeast Alaska is composed of seven entire boroughs and two census areas, in addition to the portion of the Yakutat Borough lying east of 141° West longitude. Although it has only 6.14 percent of Alaska's land area, it is larger than the state of Maine, and almost as large as the state of Indiana.

Southeastern Area

Southeast Alaska covers an area about 500 miles in length from the U.S./Canada border just below Prince of Wales Island north to Yakutat and to Cape Suckling.

Southcentral is a playground of Alaska activities, from legendary salmon fishing on the Kenai River and Copper River Valley to hiking in the Chugach National Forest to whale watching in Kenai Fjords National Park.

South Central Alaska is home to a diversity of landscapes, including dense temperate rainforests, rocky beaches, and vast glaciers. Below treeline, particularly on the Kenai Peninsula and the other coastal areas within the region, forests of Sitka spruce, subalpine fir, and mountain hemlock abound.

What are the major settlements in South Central Alaska? ›

The major city is Anchorage. Other major towns include Palmer, Wasilla, Kenai, Soldotna, Homer, Seward, Valdez, and Cordova.

In addition to copper, the mines also produced a significant amount of silver. Today, gold is the primary metal mined in Southeast Alaska, although recent discoveries of silver, zinc, and lead in commercial quantities have led to new mines.

Alaska is blessed not only with record deposits of gold but also with an extensive variety of non-precious metal minerals and gemstones, a few of the most common include Alaskan jade, rhodonite, fluorite, garnet, cinnabar, and jasper.

Alaska's parks have active geologic features such as surging and retreating glaciers, simmering volcanoes, thawing permafrost, geological hazards (such as landslides), and fossils that tell us about the active geology of the past and present.

The U.S. purchased Alaska from Russia in 1867. In the 1890s, gold rushes in Alaska and the nearby Yukon Territory brought thousands of miners and settlers to Alaska. Alaska was granted territorial status in 1912 by the United States of America.

We are famous for the Iditarod, gold mining, sourdough, the Alaska Railroad, aviation, Alaska Native heritage, homesteading, world-class fishing and seafood, outdoor adventures, fresh air, and a slower, more self-sufficient way of life.”

Hematite has also been called “Black Alaskan Diamond” although it is neither black nor a Diamond. However, “bloodstone” in North America refers to a dark green mineral with flecks of red in it (named because these red flecks look to some like splatters of blood).

Blackstone Glacier starts at an elevation of about 5,000 feet (1,500 m) in the Kenai Mountains and flows generally north for 7 miles (11 km) and terminates at tidewater at the head of Blackstone Bay, about 87 miles (140 km) west-southwest of Valdez and 8 miles (13 km) south of Whittier, Alaska.

Alaska, known for abundant wildlife, incredible fishing, stunning scenery, and of course oil, offers very little to the fluorescent world--at least so far.

The oldest confirmed prehistoric sites in Alaska belong to the Eastern Beringian Tradition, dating from about 14,000 to 12,000 years ago.

What is the oldest rocks ever found in the United States? ›

Morton gneiss, also known as rainbow gneiss, is an Archean-age gneiss found in the Minnesota River Valley of southwestern Minnesota, United States. It is one of the oldest stones on Earth, at about 3.5 billion years old.

The really old rocks in America are found in Wyoming and the states around Minnesota. They date from the Paleoarchean Era and are more than 3 billion years old.

It is illegal to remove natural or cultural artifacts (plants, animals, bones, rocks, etc.) from the park.

Amateur geology or rock collecting (also referred to as rockhounding in the United States and Canada) is the non-professional study and hobby of collecting rocks and minerals or fossil specimens from the natural environment.

Sell to a Rock Shop

Ideally, if you found a local rock shop to do business with, this would be a great source of selling your collection. This is a very common way to sell rocks for part-time rock hunters. You can easily search for a local rock shop and establish a relationship.

Established in 1972 and celebrating over 50 years in business, Sealaska is the Alaska Native regional corporation for Southeast Alaska. Our 25,000 shareholders are Tlingit, Haida and Tsimshian people with more than 10,000 years of ancestral ties to the oceans, forests and communities of Southeast Alaska.

The largest cities in the region are Juneau, Sitka, and Ketchikan. This region is also home to Hyder, the easternmost town in Alaska.

Adak is the southernmost community in Alaska and on the same latitude as Haida Gwaii in Canada, and Brussels, Belgium. It is less than three degrees of latitude north of the 49th parallel, which forms the western part of the land border between the Contiguous United States and Canada.

Ruby is located on the south bank of the Yukon River. The village is on the western border of Nowitna National Wildlife Refuge and is one of two villages (Tanana is the other) that serve as staging points for expeditions into the 1,560,000-acre preserve.

JUNEAU, Alaska - A gemstone, billed as one of the largest gem-quality opals ever found, was sold for $143,750 at auction in Alaska on Sunday. The opal, dubbed the "Americus Australis," weighs more than 11,800 carats, according to the auction house Alaska Premier Auctions & Appraisals. It also has a long history.

What rock is turquoise with brown spots? ›

Limonite creates dark brown markings in turquoise, while sandstone creates tan markings. These markings are remnants of the host rock within the turquoise, and can resemble splotches or veins. They're called matrix.

Diamond is the hardest known mineral. It is a high-symmetry allotrope of carbon (C). It has a Mohs “scratch” hardness of 10, which makes it the hardest mineral.

Microscopic grains of dead stars are the oldest known material on the planet — older than the moon, Earth and the solar system itself. By examining chemical clues in a meteorite's mineral dust, researchers have determined the most ancient grains are 7 billion years old — about half as old as the universe.

Bengaluru: A meteorite that landed in the Sahara Desert last year has been dated as being 4.56 billion years old, which makes the volcanic rock older than Earth, which is approximately 4.54 billion years old.

Alaska White granite is a frosty blend of pale silver and frosty whites, marketed with warm neutrals and onyx hues. Imported from Brazil, this durable natural stone is available in a range of slab sizes.

In Alaska, you can find amethyst crystals in the granite-rich uplands regions of Northway and Tok. You will generally find these amethysts as light pinkish-purple crystals either as parallel growing groups or single crystals.

Alaska's parks have active geologic features such as surging and retreating glaciers, simmering volcanoes, thawing permafrost, geological hazards (such as landslides), and fossils that tell us about the active geology of the past and present.

Rugged mountain summits, rounded mountain summits, and glacier landforms comprise the association.

Southeast Alaska lies at the heart of the North American temperate rainforest — a forest that extends in a narrow 2,500-mile coastal strip from northern California, along coastal British Columbia, and to the eastern edge of the Kodiak archipelago in southcentral Alaska.

The Queen Charlotte-Fairweather fault in southeastern Alaska is analogous to California's San Andreas fault, both in length and type (strike-slip). Both faults form a boundary where two blocks of Earth's crust—the North American and Pacific tectonic plates—slide horizontally past each other in opposite directions.

What type of rock is Alaska Range? ›

It is mainly igneous rock granite. Denali's granite formed below the Earth's crust as part of a batholith.

Southcentral Alaska contains several dormant and active volcanoes. The Wrangell Volcanoes are older, lie in the East, and include Mount Blackburn, Mount Bona, Mount Churchill, Mount Drum, Mount Gordon, Mount Jarvis, Mount Sanford, and Mount Wrangell.

Southeast Alaska, often abbreviated to Southeast or Southeastern, and sometimes called the Alaska(n) Panhandle, is the southeastern portion of the U.S. state of Alaska, bordered to the east and north by the northern half of the Canadian province of British Columbia (and a small part the Yukon Territory).

Alaska ranks among the top 10 areas in the world for the following minerals: coal, copper, lead, coal, zinc, and silver. Mining and minerals support an extremely lucrative part of the Alaskan economy - managed by the Department of Natural Resources.

The moist and mild climate of Southeast Alaska allows lush vegetation to flourish at high latitudes. Rainfall is abundant throughout the year, though April, May, and June mark a distinct dry season. The cloud cover and persistent rains of July mark the end of the dry season during a “typical summer” in Southeast.

The climate in Juneau and the Southeast panhandle is a mid-latitude oceanic climate (Köppen climate classification Cfb) in the southern sections and an oceanic, marine subpolar climate (similar to Scotland, or Haida Gwaii), (Köppen Cfc) in the northern parts. Much of the southern parts are temperate rainforest.

Matthew Island. The small grouping of uninhabited islands is over 300 kilometers across the Bering Sea from the mainland, making it the most remote location in Alaska. Even after the bears were gone, the archipelago remained a difficult place for people.

As the plate inches toward the northwest, it grinds past Southeast Alaska and British Columbia. Unlike the subduction zone, these faults slip primarily in a side-to-side motion, with a different tectonic plate on each side.