Hello, everyone! You might want to know more about Christmas. Thank you for visiting my blog! Christmas is my favorite holiday. In Argentina, the weather is almost always warm at Christmas. Preparations for Christmas begin very early in December and … Continue reading
Hey there! I’m researching rocks because I’m curious about them. I also like rocks because they are so interesting. Enjoy!
Geologists define rocks as aggregate of minerals. Minerals are naturally occurring, not unhealthy substances with specific chemical compositions and structures. A rock can be filled of many crystals of one or more minerals, or combinations of many minerals. Several exceptions, such as coal and obsidian, are not composed of minerals but are thought to be rocks.
People often use rocks for include building materials, roofs, sculpture, jewelry, tombstones, chalk, coal for heat, and more. Oil and natural gas can also be found in rocks. Many metals like a fork are made from rocks known as ores. Even, prehistoric humans used rocks as early as 2,000,000 B.C. Flint and other hard rocks were very important raw materials for crafting arrowheads and other special natural made rocks.
Around 500,000 B.C., rock caves and structures made from stones had become important forms of shelter for early man. During that time, early men had learned to use fire, a development that allowed humans to cook food as needed to survive and greatly expand their geographical range. Eventually, most likely no sooner than 5000 B.C., humans had realized that minerals such as gold and copper could be from rocks. Tons of ancient monuments were crafted from stone, including the pyramids of Egypt, built from limestone about 2500 B.C., and the buildings of Chichen Itza in Mexico, also of limestone, built near A.D. 450.
Since the 1500s, scientists have studied minerals and mining, fundamental aspects of the study of rocks. Georg Bauer published Concerning Metallic Things in 1556. By 1785, the British geologist James Hutton published Theory of the Earth, in which he explained his observations of rocks in Great Britain and his conclusion that Earth is much older than previous scientists before him had guessed. Geologists are scientists who study the earth and rocks, distinguish three main groups of rocks: igneous rocks, sedimentary rocks, and metamorphic rocks.
These distinctions are made on the basis of the types of minerals in the rock, the shapes of individual mineral grains, and the overall texture of the rock, all of which indicate the environment, pressure, and temperature in which the rock was made. Igneous rocks form when magma is below the land of the Earth or lava at the land of the Earth hardens. The minerals in the rock will make crystals or grow together so that the separate crystals make 1 crystal altogether. Igneous rocks and magma make up much of the oceanic and continental crust, as well as most of the rock deeper in the Earth.
Igneous rocks can be identified by the interlocking appearance of the crystals in them. Typical igneous rocks do not have a layered texture, but exceptions exist. For example, in large bodies of igneous rock, relatively thick crystals that are made early can sink to the bottom of the magma, and less thick layers of crystals that are made later can accumulate on top. Igneous rocks can form deep within the Earth or at the surface of the Earth in volcanoes.
In general, igneous rocks that form deep within the Earth have large crystals that indicate a longer period of time during which the magma cools. Igneous rocks that form at or near the surface of the Earth, such as volcanic igneous rocks, cool quickly and contain smaller crystals that are difficult to see without magnification. Obsidian, also called volcanic glass, cools down so fast that no crystals are made. Nevertheless, obsidian is considered to be an igneous rock.
Igneous rocks are classified on the basis of how much minerals there are and the size of the crystals in the rock. Extrusive igneous rocks have small crystals and crystallize at or near the Earth’s surface. Intrusive igneous rocks cool slowly below the Earth’s surface and have larger crystals. Rocks made up of thick, dark-colored minerals like olivine, pyroxene, amphibole, and plagioclase are called mafic igneous rocks.
Light-colored, less thick minerals, including quartz, mica, and feldspar are called felsic igneous rocks. Common igneous rocks include the felsic igneous rocks granite and rhyolite, and the mafic igneous rocks gabbro and basalt. Granite is an intrusive igneous rock that includes large crystals of the minerals quartz, feldspar, mica, and amphibole that form deep within the Earth. Rhyolite includes the same minerals, but forms as extrusive igneous rock near the surface of the Earth or in volcanoes and cools quickly from magma or lava, so its crystals are difficult to observe with the naked eye.
Similarly, gabbro is more coarse-grained than basalt and made deeper down in the Earth, but both rocks include the minerals pyroxene, feldspar, and olivine. Fabulous exposures of igneous rocks occur in the volcanoes of Hawaii, volcanic rocks of Yellowstone National Park are located in Wyoming, Idaho, Montana, in Lassen Volcanic National Park and Yosemite National Park in California. Sedimentary rocks are those made of grains of preexisting rocks or organic material that, in most cases, have been eroded, deposited, compacted, and cemented together. They typically form at the surface of the Earth as sediment moves as a result of the action of wind, water, ice, gravity, or a combination of these.
Sedimentary rocks also form as chemicals precipitate from seawater, or through accumulation of organic material such as plant debris or animal shells. Common sedimentary rocks include shale, sandstone, limestone, and conglomerate. Sedimentary rocks typically have a layered appearance because most sediments are deposited in horizontal layers and are buried beneath later deposits of sediments over long periods of time. Sediments deposited rapidly, however, tend to be poorly layered if layers are visible at all.
Sedimentary rocks are made in many different environments at the surface of the Earth. Eolian, or wind blown, sediments can accumulate in deserts. Rivers carry sediments and deposit them along their banks or into lakes or oceans. Glaciers make unusual deposits of a wide variety of sediments that they pick up as the glacier expands and moves; glacial deposits are well exposed in the northern United States. Sediments can travel in currents below sea level to the deepest parts of the ocean floor.
Secretion of calcium carbonate shells by reef-building organisms produce large quantities of limestone. Evaporation of seawater has resulted in the formation of widespread layers of salt and gypsum. Swamps rich in plants can produce coal if organic material accumulates and is buried before aerobic bacteria can destroy the dead plants. Sedimentary rocks are classified on the basis of the sizes of the particles in the rock and the composition of the rock.
Clastic sedimentary rocks comprise fragments of preexisting rocks and minerals. Chemical precipitates are sedimentary rocks that are made by precipitation of minerals from seawater, salt lakes, or mineral-rich springs. Organic sedimentary rocks formed from organic matter or organic activity, such as coal and limestone made by reef-building organisms like coral. Grain sizes in sedimentary rocks range from fine clay and silt to sand to boulders.
The sediment in a sedimentary rock reflects its environment of deposition. For example, wind-blown sand grains commonly is evidence of abrasion of their surfaces as a result of colliding with other grains. Sediments transported long distances tend to decrease in size and are more rounded than sediment deposited near their precursor rocks because of wearing against other sediments or rocks. Large or heavy sediments tend to wear out of water or wind if the energy of the water or wind is insufficient to carry the sediments.
Sediments deposited rapidly as a result of slides or slumps tend to include a larger range of sediment sizes, from large boulders to pebbles to sand grains and flakes of clay. Such rocks are called conglomerate. Along beaches, the rhythmic activity of waves moving sediment back and forth produces sandstones in which the grains are well rounded and of similar size. Glaciers pick up and carry a wide variety of sediments and often scratch or scrape the rocks over which they travel.
Sedimentary rocks are the only rocks in which fossils can be preserved because at the elevated temperatures and pressures in which igneous and metamorphic rocks form, fossils and organic remnants are ruined. The presence of fossils and the types of fossil organisms in a rock provide clues about the environment and age of sedimentary rocks. For example, fossils of human beings are not present in rocks older than approximately two million years because humans did not exist before then. Similarly, dinosaur fossils do not occur in rocks younger than about 65 million years because dinosaurs became extinct at that very time.
Fish fossils in sedimentary rock indicate that the sediments that make up the rock were deposited in a lake, river, or marine environment. By establishing the environment of the fossils in a rock, scientists learn more about the conditions under which the rock formed.
Spectacular exposures of sedimentary rocks include the Grand Canyon which is in Arizona, the eolian sandstones of Zion National Park which is in Utah, the limestones of Carlsbad National Park which is in New Mexico, and glacial features of Voyageurs National Park which is in Minnesota. Metamorphic rocks are named for the process of change that affects rocks. The changes that make metamorphic rocks usually include rises in the temperature (generally to 392°F) and the pressure of a precursor rock, which can be igneous, sedimentary, or metamorphic, to a degree that the minerals in the rock are no longer stable. The rock might change in mineral content or appearance, or even both. Clues to identifying metamorphic rocks include the presence of minerals such as mica, amphibole, staurolite, and garnet, and layers in which minerals are aligned as a result of pressure applied to the rock.
Common metamorphic rocks include slate, schist, and gneiss. Metamorphic rocks commonly are made in mountains such as the Appalachian Mountains, parts of California, and the ancient, eroded metamorphic rocks in the Llano Uplift of central Texas. Metamorphic rocks are classified depending on their constituent minerals and texture. Foliated metamorphic rocks are those that have a layered texture. In foliated metamorphic rocks, elongate or platy minerals such as mica and amphibole become aligned as a result of pressure on the rock. Foliation can range from alternating layers of light and dark minerals typical of gneiss to the seemingly perfect alignment of platy minerals in slate.
Some metamorphic rocks aren’t foliated and have a massive texture devoid of layers. Mineralogy of metamorphic rocks reflects the mineral content of the precursor rock and the pressure and temperature at which metamorphism occurs. As sediments undergo metamorphism, the layers of sediment can be folded or become more pronounced as pressure on the rock increases. Elongate or platy minerals in the rock tend to become aligned in the same direction.
For example, when shale metamorphoses to slate, it becomes easier to split the well-aligned layers of the slate into thin, flat sheets. This property of slate makes it an attractive roofing material. Marble-metamorphosed limestone typically does not have the pronounced layers of slate, but is used for flooring and sculptures.
Metamorphism of igneous rocks can cause the different minerals in the rocks to separate into layers. When granite metamorphoses into gneiss, layers of light-colored minerals and dark-colored minerals form. As with sedimentary rocks, elongate or platy minerals become well-aligned as pressure on the rock increases.
As sediments undergo metamorphism, the layers of sediment can be folded or become more pronounced as pressure on the rock increases. Elongate or platy minerals in the rock tend to become aligned in the same direction. For example, when shale metamorphoses to slate, it becomes easier to split the well-aligned layers of the slate into thin, flat sheets. This property of slate makes it an attractive roofing material.
Marble-metamorphosed limestone-typically does not have the pronounced layers of slate, but is used for flooring and sculptures. Metamorphism of igneous rocks can cause the different minerals in the rocks to separate into layers. When granite metamorphoses into gneiss, layers of light-colored minerals and dark-colored minerals are made. As with sedimentary rocks, elongate or platy minerals become well-aligned as pressure on the rock increases.
It is possible for metamorphic rocks to change into other metamorphic rocks. In some regions, especially areas where mountain building is taking place, it is not unusual for several episodes of change to affect rocks. It can be difficult to unravel the effects of each episode of metamorphism. The word igneous comes from the Latin word ignis which means of fire. Sedimentary rocks make layers at the bottoms of oceans and lakes.
Layers of sedimentary rocks are called strata.
I got this photo at http://www.hydroponicsnewyorkcity.com/wp-content/uploads/2014/02/river-rocks.jpg but originally Google Images.
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Hi there! My mother, Camilla, suggested that I write a series of posts about birds on my blog since I’ve been talking about them and learning about them. Please let me know if you have any bird books, CDs, or a website you’d recommend! Here is the part about California Quail.
California Quail are plump, short-necked game birds with a small head and bill. They fly on short, very broad wings. The tail is fairly long and square. Both sexes have a comma-shaped topknot of feathers projecting forward from the forehead, longer in males than females. Adult males are rich gray and brown, with a black face outlined with bold white stripes. Females are a plainer brown and lack the facial markings. Both genders have a pattern of white, creamy, and chestnut scales on the belly. Young birds look like females but have a shorter topknot.
California Quail spend most of their time on the ground, walking and scratching in search of food. In morning and evening they forage beneath shrubs or on open ground near cover. They usually travel in groups called coveys. Their flight is explosive but lasts just long enough to reach cover.
You’ll find California Quail in chaparral, sagebrush, oak woodlands, and foothill forests of California and the Northwest. They’re quite tolerant of people and can be common in city parks, suburban gardens, and agricultural areas. The California quail is a small, plump bird with a short black beak. The male has a gray chest and brown back and wings. It has a black throat with white stripes and a brown cap on its head. The female has a gray or brown head and back and a lighter speckled chest and belly. Both the male and the female have a curved black crown feather on their foreheads. The male’s crown feather is larger than the female’s.
The California quail is sometimes called the valley quail. The California quail eats seeds, plant parts like buds and sometimes insects. They feed in flocks in the early morning. The California quail can be found from southern Oregon to southern California and east into Nevada. The California quail lives in grasslands, foothills, woodlands, canyons and at the edge of deserts. It likes areas with lots of brush. The California quail lives in coveys of 10 to 200 birds in the winter.
They will stay in these flocks until they pair off during mating season. Male California quails will perch on a tree or post and call out to claim their territory. The California quail will roost in trees to avoid danger and to rest. Males often compete for a mate. They will mate with only one female. Females usually lay between 12-16 cream and brown speckled eggs. Their nest is a shallow hollow or scrape in the ground that is lined with grass. The female incubates the eggs for about three weeks. Both parents will care for the chicks. The chicks leave the nest shortly after birth. They make their first attempts at flight when they are about 10 days old. They will stay on the ground for about a month and then will roost in trees with the rest of the flock.
The female usually has one brood a year. This sharply-marked bird with the curving topknot is common along the California coast and in a few other areas of the west. It has adapted rather well to the increasing human population, and is often found around well-wooded suburbs and even large city parks. California Quail live in coveys at most seasons, and are often seen strutting across clearings, nodding their heads at each step. If disturbed, they may burst into fast low flight on whirring wings.
The California Quail is a gray, ground-dwelling bird, more slender than most other quail. It has a light breast with scaled patterning, white streaks along brown sides, and black and gray scaling on the nape of the neck. The female has a tan head with a small feather plume. The male has a bold black face outlined in white, with a brown crown and a pendulous feather plume hanging forward from his forehead.
The California quail, California’s state bird, is a 9-11 inch hen-like bird with a distinctive teardrop-shaped head plume called a top-knot. Their plump bodies vary from grayish to brown with scaly markings on the lower breast and abdomen. Males are particularly elegant with a black throat, chestnut patch on the belly, a bluish gray breast, white speckles on its flanks, and a white stripe on the forehead and around the neckline. Females have a smaller top-knot and lack the male’s distinctive facial markings and black throat.
Her crest is dark brown and her body is brown or gray with white speckles on the chest and belly. The marked sexual dimorphism is believed to play an important part in breeding displays. Juveniles resemble the female, but have shorter and lighter colored crests. As ground dwelling birds, their short and powerful legs are well adapted for terrestrial locomotion. They can fly rapidly, but only for short distances. When alarmed they prefer to run, flying only as a last resort.
California quail are best adapted to semiarid environments, ranging from sea level to 4000 feet and occasionally up to 8500 feet or higher (Sumner 1935). As long as there is abundant food, ground cover, and a dependable water source, quail are able to live in a variety of habitats including open woodlands, brushy foothills, desert washes, forest edge, chaparral, stream valleys, agricultural lands, and suburb areas. Cover is needed for roosting, resting, nesting, escaping from predators, and for protection from the weather (Sumner 1935, Leopold 1977).
Leopold (1977) separates California quail habitat areas into four major ecological zones arid ranges mostly in Southern California and Baja California, transitional ranges in the Sacramento Valley, humid forest ranges associated with the Coast and Cascade ranges, and interior Great Basin and Columbia Basin ranges. Of these the transitional ranges in the Sacramento Valley foothills provide the most stable quail habitat, characterized by mild winters, moderate rainfall, moderately dense ground vegetation, and generally adequate ground cover.
California quail are generalists and opportunists, so food intake varies by location and season. Their main food items are seeds produced by various species of broad-leafed annual plants, especially legumes. This includes plants such as lupine (Lupinus sp.), clover (Trifolium sp.), bur clover (Medicago sp.), and deer vetches (Lotus sp.) (Leopold 1977). Their bills are typical for seedeaters: serrated, short, stout, and slightly decurved.
Shields and Duncan (1966) studied California quail diet in the fall and winter during a dry year on the San Joaquin Experimental Range in the central Sierra Nevada foothills. They found that seeds comprised 82% of their diet, while green leafage contributed 18%. Duncan (1968) also studied quail diet in the same area and found that legume seeds were their most important food item. Quail also eat leafy materials, acorns, fruits and berries, crop residues, and some insects (Leopold 1977).
During the fall and winter, California quail are highly gregarious birds, gathering into groups, called coveys. In most situations, covey size averages about 50 birds, but under intensive management and protection, coveys can get as large as 1000 birds (Leopold 1977). In the covey, the quail tend to imitate one another and exhibit cooperative behavior. For example, when one bird finds a good supply of food it often calls the others to it. Likewise, when a member of the covey perceives danger it will warn the group with the appropriate call (Sumner 1935).
California quail communicate with 14 different calls (Leopold, 1977). This includes courtship, re-grouping, feeding, and warning calls. The most frequently heard location call has been described as “cu-ca-cow” or “chi-ca-go.” At the start of nesting season in early spring the coveys break up, as quail pairs spread themselves out into different habitat areas to nest and rear their young.
At the end of summer each new quail family rejoins the others to form a new covey where they will remain until the next breeding season. Emlen (1939) observed this seasonal movement in his study of California quail on a 760-acre farm in the vicinity of Davis, California. In the winter, four coveys, containing 21-46 birds, had home ranges of 17-45 acres, roughly one acre for each bird. The covey locations and range size depended on the amount of brush cover available. The four territories were separated by 350 yards to half a mile and contact between the coveys was infrequent.
The members of a covey tended to feed and roost together in mid-winter, but occasionally they broke up into smaller units. Winter movements were restricted with only 5 to 10 acres of an entire territory utilized by the covey on any one day. The same area would serve as a feeding ground for a few days to two or three weeks when the birds would move to another part of their territory. The California quail is common to states of the Pacific coast. They were first introduced into Utah in 1869.
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