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Topic: Radiogenic

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	Radiogenic - Wikipedia, the free encyclopedia
		A radiogenic nuclide is one that is produced by a process of radioactive decay.
		Lead is perhaps the best example of a radiogenic substance, as it is produced from the radioactive decay of uranium and thorium.
		Other substances considered radiogenic are argon-40, formed from radioactive potassium, and nitrogen, which is formed by the decay of carbon-14.
	en.wikipedia.org /wiki/Radiogenic (95 words)

	Isochron dating - Wikipedia, the free encyclopedia
		All forms of isochron dating assume that the source of the rock or rocks contained unknown amounts of both radiogenic and non-radiogenic isotopes of the daughter element, along with some amount of the parent nuclide.
		Thus, at the moment of crystallization, the ratio of the concentration of the radiogenic isotope of the daughter element to that of the non-radiogenic isotope is some value independent of the concentration of the parent.
		As time goes on, some amount of the parent decays into the radiogenic isotope of the daughter, increasing the ratio of the concentration of the radiogenic isotope to that of the daughter.
	en.wikipedia.org /wiki/Isochron_dating (722 words)

	Information Handout: Radiogenic Isotopes and the Eastern Mineral Resources Program of the USGS
		As the physical laws governing radioactive decay are universally obeyed, radiogenic isotope dating techniques represent a quantitative method to reliably establish the age of materials in Nature, applicable even to the oldest objects on the Earth, the Moon, meteorites, and asteroids and, potentially, in the rest of the universe.
		Isotopes used for age determinations include radiogenic Sr (strontium produced by decay of radioactive rubidium), Nd (neodymium from decay of samarium), and Os (osmium from decay of rhenium); application of all radiogenic systems requires knowledge of the appropriate half-lives and chemical analyses to detect the relative abundances of parents and daughters.
		Radiogenic isotope tracers can be powerful tools to look for environmental and geochemical pathways, to establish the relative timing of chemical contributions to urban water reservoirs, and to discriminate between results of natural processes and results of human activities in the near-surface environment.
	pubs.usgs.gov /info/ayuso2 (2256 words)

	Radiogenic tube radiological device with magnetic bearings - Patent 4780900
		The anode is rotated by a drive motor comprising a rotor disposed inside the radiogenic tube along the rotational axis of the anode, and including a stator disposed concentrically with the rotor and outside the envelope of the radiogenic tube.
		The high voltage required for operation of the radiogenic tube, supplied by a high voltage generator, is brought to the radiogenic tube by cables having a high level of electrical insulation; the negative polarity being applied to the cathode of the radiogenic tube and the positive polarity being applied to the anode.
		Such a combination may be reproduced for feeding into the radiogenic tube 5, possibly simultaneously, other electric signals (not shown) by using one or more of the conductors 22, 23 other than the common conductor, which is formed in the example described by the first conductor 21.
	www.freepatentsonline.com /4780900.html (2439 words)

	Naturally occurring radiogenic isotopes make effective groundwater flow tracers
		However, radiogenic isotopes may provide a simpler story to read because their evolution is less complex.
		The aquifer rocks are primarily basalts with a limited range of radiogenic isotope ratios--making the area an ideal location for this research.
		In their paper, the research team contends that radiogenic element analyses could simplify groundwater flow interpretations and should be routinely performed in groundwater studies.
	www.eurekalert.org /pub_releases/2000-12/INEE-Nori-1312100.php (981 words)

	[No title] (Site not responding. Last check: 2007-08-19)
		As an initial matter, it is necessary to determine whether paragraphs (b)(3) and (b)(4) purport to preclude a claimant from establishing that he or she incurred polycythemia vera as the result of exposure to ionizing radiation in service.
		The Federal Circuit has stated that a determination that a particular disease is radiogenic “relieves the claimant of the need to show that it is possible that in-service exposure to ionizing radiation may have been a precipitating factor for the disease.” Ramey v.
		We note further that a determination that a disease is radiogenic entitles claimants seeking service connection for such diseases to have their claims developed and adjudicated under the guidelines established by VA pursuant to Pub.
	www1.va.gov /ogc/docs/prc15-99.doc (2135 words)

	Alma Ramey v Hershel Gober
		First, she contended that her husband's death resulted from liver cancer, a radiogenic disease as to which there is a statutory presumption of service connection.
		Veterans and their survivors who attempted to establish direct service connection were seldom successful under that regime because of the severe difficulties of proof, including the lack of ready access to scientific and medical evidence about the long-term effects of radiation exposure and the lack of reliable information about exposure levels.
		By identifying particular diseases as radiogenic, the regulation relieves the claimant of the need to show that it is possible that in-service exposure to ionizing radiation may have been a precipitating factor for the disease.
	www.ll.georgetown.edu /federal/judicial/fed/opinions/96opinions/96-7055.html (9452 words)

	Global Change 1: Clocks in Rocks
		A useful analogy to illustrate the fundamentals of geochronology is an hourglass.
		A complication occurs in natural samples because at the time the radiogenic clock starts ticking, the sample already contains some daughter material; in other words, some sand is already present in the daughter chamber even before we begin measuring time.
		Radiogenic age measurements on rock and minerals from Earth are not that old.
	www.globalchange.umich.edu /globalchange1/current/lectures/clocks_in_rocks/clocks_in_rocks.html (1166 words)

	Articles / Impact / Dubious Radiogenic Pb Places U-Th-Pb Mineral Dating in Doubt - Institute for Creation Research
		It must be assumed that when the zircon grains crystallized, no radiogenic Pb was in them, and that all the radiogenic Pb now measured was derived by radioactive decay from U and Th.
		However, there are several lines of evidence that indicate radiogenic Pb can be inherited during crystallization of the mineral grains, and that open-system behavior is common, with radiogenic Pb lost by diffusion due to the way the Pb is held in the crystal lattice.
		Radiogenic Pb is easily lost by diffusion from some crystals and the process is accelerated by heat, water, radiation damage, and weathering, while in other crystals it is inherited in excess.
	www.icr.org /index.php?module=articles&action=view&ID=462 (1786 words)

	OSMIUM ISOTOPE SYSTEMATICS: OBSERVATIONS FROM THE CASCADE ARC (Site not responding. Last check: 2007-08-19)
		Radiogenic Os isotope compositions have been recognized for several convergent arcs, including the Andes, Mexico, Java, and Cascade arcs.
		Debate has centered on the origin of such radiogenic compositions, with models advocating either subducted slab components or interaction with the crust.
		Radiogenic Os isotope compositions also do not correlate with any existing Sr, Nd, or Pb data.
	gsa.confex.com /gsa/2001AM/finalprogram/abstract_28675.htm (406 words)

	Ramey v. Gober (Site not responding. Last check: 2007-08-19)
		That point is underscored in the succeeding subparagraph, in which the Act directs the DVA to include the factors to be considered in deciding "whether or not service connection should be granted in individual cases." § 5(b)(2)(A)(iii), 98 Stat.
		Any doubt as to Congress's understanding of the effect of section 3.311 is put to rest by the congressional analysis of the 1984 Act and the DVA regulation that is reflected throughout the legislative history of the 1988 Act.
		It may be that the court in Combee used the term "presumption of service connection" to refer to the procedural advantages enjoyed by claimants who establish that they are entitled to have their claims processed under section 3.311.
	lw.bna.com /lw/19970826/967055.htm (4571 words)

	Radiogenic unit - Patent 5497409
		A radiogenic unit includes an X-ray tube having an anode disposed at a first end thereof and a cathode disposed at a second end thereof, a high-voltage supply circuit which supplies power to the X-ray tube in single pole mode and which includes a heating transformer for the cathode, and a casing.
		The invention relates to a radiogenic unit and to its cooling system, enabling high power to be obtained while at the same time keeping the external casing of the apparatus cool.
		The casing for the radiogenic unit according to the invention furthermore comprises two parts that are imperviously sealed against fluids and X-rays and are hermetically secured to each other.
	www.freepatentsonline.com /5497409.html (4047 words)

	Heat Flow in Texas
		The variation in heat flow across Texas can be explained by a combination of three factors: changes in the radiogenic heat production of the basement, heat generation within sediments, and the effect of large scale aquifer flow.
		In spite of the high heat generation values of the Mesozoic fl shales, the total sedimentary radiogenic contribution for the wells east of Ouachita Tectonic front can be neglected.
		Further to the east, in the proximity of the Gulf Coast, the radiogenic heat generation could become important due to the large thickness of the sedimentary column.
	geology.heroy.smu.edu /~negraru/Heat_texas (683 words)

	USGS Analytical Methods Development (Radiogenic and Stable Isotopes
		Work is focused on developing radiogenic and stable isotope analytical techniques to support mineral- and environmentally-related geologic investigations.
		Radiogenic isotope techniques are used for analysis of materials, fluids, and fluid and solid inclusions from ancient and modern environments.
		New analytical procedures are being developed for studies directed at: regional and site-specific metal mobilization, metal transport, redistribution processes, and sources of fluids for regional geologic, ore genesis, life-cycles, and environmental applications.
	minerals.usgs.gov /east/analytical (89 words)

	Radiogenic Isotopes - TIMS
		Radiogenic isotopic tracers (Pb, Sr, Nd, Sr, U) can be used to provide information regarding geologic processes such as magma evolution, sources of magmas and sediments, eolian dust transport, sources of metals (human-caused or natural in various ecosystems), and ñbaselineî data for environmentally pristine ecosystems.
		Radiogenic isotopes can also be used to trace groundwater flow paths and as indicators of mixing of waters from discrete aquifers.
		Capabilities in the Radiogenic Isotope Facility are also used to provide concentration data for toxic or economically important elements such as Cd, In, Ag, Tl, U, and Pb, which may be present at levels below the detection limit of other techniques.
	crustal.usgs.gov /projects/isotope_geochron_labs/task2.html (1005 words)

	LithoMec.nb
		The quantity of radiogenic heat produced per unity of time in a small cylinder of rock is:
		This equation allows to determine the temperature profile for the domain 0
		This equation is valid for an homogeneous distribution of radiogenic element i.e.
	www.geosci.usyd.edu.au /users/prey/Teaching/Litho (3479 words)

	Isochron Dating
		Moreover, the daughter atoms produced by decay in a mineral are isotopes of different elements and have different ionic charges and radii compared with their parents.
		Partial homogenization of radiogenic daughter (in some exceptional cases) results in an apparently valid isochron of reduced age.
		These exceptions should be of little comfort to young-Earthers, for (1) they are uncommon (extremely uncommon in the case of partial resetting); and (2) the result in both cases is an isochron age which is too young to represent the time of formation.
	www.talkorigins.org /faqs/isochron-dating.html (5756 words)

	Radiogenic Isotope Geology - Cambridge University Press
		Modern isotope geochemistry is a rapidly expanding field that has a part to play in a broad range of earth and planetary sciences - from extra-solar system processes to environmental geoscience.
		This book provides a comprehensive review of the field of radiogenic isotope geology and highlights the use of isotopic dating and tracer studies in solving geological problems.
		The author presents current ideas in their historical context, thereby leading the reader to an appreciation of the development of modern interpretations.
	www.cambridge.org /catalogue/catalogue.asp?isbn=0521598915 (355 words)

	[No title] (Site not responding. Last check: 2007-08-19)
		Although the course is divided into two equal sections, covering radiogenic and stable isotopes respectively, it is the aim of the course to provide the student with an insight of the complementary nature of the two areas of study and the interconnections between them.
		Radioactive and Radiogenic Isotopes: This section of the course, taught by P. Deines, begins with a discussion of the formation of the elements and the instrumentation used to determine isotopic composition variations.
		In addition, students prepare a 10 page report on any aspect of geochronology, or the application of radiogenic isotopes, that has lead to a significant advance in the understanding of a geologic process.
	www.geosc.psu.edu /Courses/Geosc416/Mainpage.html (359 words)

	ABSTRACT: Weathering versus circulation-controlled changes in radiogenic isotope tracer composition of the Labrador Sea ... (Site not responding. Last check: 2007-08-19)
		However, it has been unclear until now as to whether the changes that have been observed in isotope composition at this time are the result of increased thermohaline circulation or due to the effects of increased glacial weathering.
		In this paper we adopt a box model approach to demonstrate that the shifts in radiogenic isotope compositions are unlikely to be due to changes in convection in LSW but can be explained in terms of increases of erosion levels due to the glaciation of Greenland and Canada.
		An important general conclusion is that the compositions of radiogenic isotopes in seawater are not always a reflection of their continental sources.
	cgrg.geog.uvic.ca /abstracts/vonWeatheringGeological.html (326 words)

	Assessment of radiogenic cancer initiation frequency per clonogenic rat mammary cell in vivo -- Clifton et al. 46 (5): ...
		Assessment of radiogenic cancer initiation frequency per clonogenic rat mammary cell in vivo -- Clifton et al.
		Assessment of radiogenic cancer initiation frequency per clonogenic rat mammary cell in vivo
		Radiogenic initiation of mammary cancer is here shown to be a common
	cancerres.aacrjournals.org /cgi/content/abstract/46/5/2390 (383 words)

	AN INCREMENTAL-ISOTHERMAL MODEL FOR RADIOGENIC ISOTOPE ACCUMULATION WITH CHANGING TEMPERATURE (Site not responding. Last check: 2007-08-19)
		Accumulation of radiogenic daughter isotope reflects decay and loss processes that are functions of time (t) and temperature (T).
		Its application, however, is restricted by several assumptions, including a monotonic cooling process and an initial zero daughter concentration that preclude many situations, for example, where heating and partially resetting are involved.
		A forward-modeling, incremental-isothermal approach is proposed to overcome these restrictions and reveal the accumulation of radiogenic isotope (and apparent age) with time in any given T-t path.
	gsa.confex.com /gsa/2001AM/finalprogram/abstract_27031.htm (369 words)

	Geologic Maps of Maryland: Eastern Piedmont Plutonic Rocks
		Moderately to strongly deformed intrusive complex composed of gneissic biotite quartz diorite, hornblende-biotite quartz diorite, and biotite granodiorite; all rocks foliated and some strongly sheared; age 550 +/- 50 m.y.* by radiogenic dating.
		Moderately to strongly deformed; igneous textures generally destroyed; composition ranges from quartz diorite to granodiorite; comprises thin concordant sheets r wedges localized along plunging crest of Baltimore anticlinorium.
		Chiefly serpentinite with partly to completely altered dunite, peridotite, pyroxenite, and massive to schistose soapstone; talc-carbonate rock and altered gabbro are common in some bodies.
	www.mgs.md.gov /esic/geo/lgdepp.html (432 words)

	Amazon.ca: Books: Radiogenic Isotope Geology (Site not responding. Last check: 2007-08-19)
		The author reviews the field of radiogenic isotope geology in a concise and visual manner to provide a comprehensive introduction to the subject and its wide variety of applications.
		The use of radiogenic isotopes as geochemical tracers and for age determinations of various sorts is now a crucial component of studies of all parts of the Earth system.
		Inevitably, a single text that tries to cover such a diverse suite of rapidly developing subdisciplines will run into some glitches and not be completely current, but Dickin has provided a very good starting point for an advanced undergraduate or graduate course in isotope geochemistry and/or geochronology.
	www.amazon.ca /exec/obidos/ASIN/0521530172 (626 words)

	Energy Citations Database (ECD) - Energy and Energy-Related Bibliographic Citations (Site not responding. Last check: 2007-08-19)
		The results indicate that the radiogenic argon is quantitatively retained at temperatures be low 400 deg C except, possibly, for the finest grain-sizes (--325 mesh) and for sanidines with lattice irregularities.
		To test possible long term (millions of years) low-temperature losses of radiogenic argon from bentonitic sanidine, seven biotite -- sanidine pairs, taken from bentonite clay horizons and ranging in age from approximately -65 to approximately -450 million years, were sampled and analyzed.
		The sets of Ar/sup 40//K/sup 40/ values obtained are the same within analytical error (plus or minus 5%) over the entire range of ages and show that bentonitic sanidine radiogenic argon as well as comparable biotite.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=4833898 (303 words)

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