In earth s crust

The U.S. Department of Energy has estimated that the total usable geothermal energy resource in Earth s crust to a depth of 10 kilometers is about 100 million exajoules, which is 300,000 times the world s annual energy consumption. Unfortunately, only a tiny fraction of this energy is extractable at a price that is competitive in today s energy market. 

Abundance of elements in earth s crust, see Elements, abundance in earth s crust Acetaldehyde structure, 332 Acetamide, 338 Acetanilide, 344 Acetic acid in biochemistry, 428 structure, 333 Acetone... 

Many scientists thought that Earth must have formed as long as 3.3 billion years ago, but their evidence was confusing and inconsistent. They knew that some of the lead on Earth was primordial, i.e., it dated from the time the planet formed. But they also understood that some lead had formed later from the radioactive decay of uranium and thorium. Different isotopes of uranium decay at different rates into two distinctive forms or isotopes of lead lead-206 and lead-207. In addition, radioactive thorium decays into lead-208. Thus, far from being static, the isotopic composition of lead on Earth was dynamic and constantly changing, and the various proportions of lead isotopes over hundreds of millions of years in different regions of the planet were keys to dating Earth s past. A comparison of the ratio of various lead isotopes in Earth s crust today with the ratio of lead isotopes in meteorites formed at the same time as the solar system would establish Earth s age. Early twentieth century physicists had worked out the equation for the planet s age, but they could not solve it because they did not know the isotopic composition of Earth s primordial lead. Once that number was measured, it could be inserted into the equation and blip, as Patterson put it, out would come the age of the Earth. ... 

Metal Chemical symbol Abundance in earth s crust (ppm) Density (g/cm3) Melting point (°C) Hardness (Mohs scale)... 

Elemental uranium, crystal structures of, 25 409. See also Uranium (U) Elementary reaction, 21 336 Element/isotope ratios, in fine art examination/conservation, 11 419 Element mapping, in fine art examination/ conservation, 11 406 Element names/symbols, 17 386-387 transfermium, 17 387t Elements, in earth s crust, 26 23 a-Eleostearic acid, physical properties, 5 33t... 

To return to our case study of iron, the equilibrium concentration of Fe(III) is ultimately controlled by its mineral solubility. Since atmospheric dust is a major source of new iron to the ocean, its solubility is a matter of hot debate. If the solubility is low, the particulate iron is likely to settle out of the euphotic zone before it can be assimilated by plankton. Iron is one of the most abundant elements in Earth s crust, so it is not surprising that concentrations in dust are high, ranging from 3 to 5% dry weight. 

Chemical Elements in Order of Abundance in Earth s Crust... 

List of Elements of the Periodic Table—Sorted by Abundance in Earth s crust. http //www. science.co. ilPTelements. asp s=Earth (accessed December 2, 2005). 

The element was discovered by Lord Raleigh and Sir William Ramsay in 1894. Argon is the third most abundant element in the atmosphere. Its concentration in air is 0.934% by volume. Also, it occurs in earth s crust at a concentration of 3.4 mg/kg, and in the sea water at 4.3 pg/L. It was most likely formed in earth crust by radioactive decay of K-40 and seeped out into the... 

Chromium occurs in the minerals chromite, Fe0 Cr203 and crocoite, PbCr04. The element is never found free in nature. Its abundance in earth s crust is estimated in the range 0.01% and its concentration in sea water is 0.3 qg/L. The element was discovered by Vaquelin in 1797. 

Rhenium does not occur alone in nature in elemental form. It is found in trace quantities in a number of minerals such as columbite, gadolinite, molybdenite, tantalite, wolfranite, and many platinum ores. Its average concentration in earth s crust is 0.0007mg/kg. 

Large thorium deposits have heen found in many parts of the world. It occurs in minerals thorite, ThSi04, and thorianite, Th02"U02. Thorium also is found in mineral monazite which contains between 3 to 9% Th02. Th02 is the principal source of commercial thorium. Abundance of thorium in earth s crust is estimated at about 9.6 mg/kg. Thorium and uranium are believed to have contributed much of the internal heat of the earth due to their radioactive emanations since earth s formation. 

The element was discovered in 1794 by the Swedish chemist Gadolin. He named it after the small town Ytterby in Sweden where the mineral containing yttria was found. Mosander in 1843 determined that the yttria consisted of three oxides yttria, erbia, and terbia. Yttrium occurs in all rare earths. It is recovered commercially from monazite sand, which contains about 3% yttrium. It also is found in bastnasite in smaller amounts of about 0.2%. Abundance of yttrium in earth s crust is estimated to be 33 mg/kg. The metal has been detected in moon rocks. 

Zinc occurs in nature, widely distributed. The principal ores are sphalerite (and wurtzite) known as zinc blende, ZnS gahnite, ZnAl204 calamine smith-sonite, ZnCOs franklinite, ZnFe204 and zincite, ZnO. Abundance in earth s crust is about 70 mg/kg and average concentration in sea water is about 10 pg/L. 

Dissolving an eggshell in vinegar demonstrates a modern environmental problem. Calcium carbonate is present in Earth s crust as marble, limestone, and chalk. Many modern buildings, statues, and stone structures contain calcium. Acid rain is slowly dissolving these structures. 

TABLE 9.12 Abundance in Earth s Crust of Some of the Most Common Crustal Elements and Those Commonly Found in Atmospheric Aerosols or Used as a Tracer"... 

We begin with a discussion of the most common minerals present in Earth s crust, soils, and troposphere, as well as some less common minerals that contain common environmental contaminants. Following this is (1) a discussion of the nature of environmentally important solid surfaces before and after reaction with aqueous solutions, including their charging behavior as a function of solution pH (2) the nature of the electrical double layer and how it is altered by changes in the type of solid present and the ionic strength and pH of the solution in contact with the solid and (3) dissolution, precipitation, and sorption processes relevant to environmental interfacial chemistry. We finish with a discussion of some of the factors affecting chemical reactivity at mineral/aqueous solution interfaces. 

In the next three subsections, we discuss the most important minerals in Earth s crust, soils, and atmosphere, and explore some of the basic concepts that help guide our thinking about their interactions with water, aqueous metal ions, organic matter, microbial organisms, and atmospheric and soil gases. 

Common minerals in Earth s crust, types of weathering reactions, activation energies, and weathering products. 

Plutonium has a short half-life (24,360 years), so any plutonium initially in Earth s crust has long since decayed. The same is true for any heavier elements with even shorter half-lives from which plutonium might originate. Trace amounts of plutonium can occur naturally in U-238 concentrations, however, as a result of neutron capture, where U-238 becomes U-239 and after beta emission becomes Np-239 and after further beta emission becomes Pu-239. (There are elements in Earth s crust with half-lives even shorter than plutonium s, but these are the products of uranium decay—between uranium and lead in the periodic table of elements.)... 

The nuclear fuel cycle (Fig. 16.1) begins with the mining of uranium ore. Uranium is by no means rare. Its overall abundance in Earth s crust is 4 ppm (which is more abundant than Ag, Hg, Bi, or Cd). There are 104 tonnes of uranium in Earth s crust. The problem is one of concentration in that most uranium deposits contain <0.001% uranium. 

Fluorine, the first element of the group, is the halogen of greatest abundance in Earth s crust. It occurs widely in many minerals, including... 

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