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Timing is Everything:The Boon and Bane of 14C Geochronology

Description: There are underappreciated limitations of the conversion of {sup 14}C-ages to the fixed, calendrical time-scale that bear directly upon our understanding of the dynamic climate system, or the relationship between the collapse of one civilization and it's neighbor's. In this paper we present a quantitative assessment of the limits of {sup 14}C-geochronology and calibration onto the absolute calendrical time-scale over the Holocene. We take into account not only the inherent limitations of the {sup 14}C-calendar calibration curve, but also analytical uncertainties.
Date: October 29, 2004
Creator: Guilderson, T; Guilderson, T; Reimer, P J & Brown, T
Partner: UNT Libraries Government Documents Department

Holocene left-slip rate determined by cosmogenic surface dating on the Xidatan segment of the Kunlun Fault (Qinghai, Chin

Description: Cosmogenic dating, using in-situ <sup>26</sup>A1 and <sup>10</sup>Be in quartz pebbles from alluvial terrace surfaces, constrains the late Holocene slip rate on the Xidatan segment of the Kuniun fault in northeastern Tibet. Two terrace risers offset by 24 ± 3 and 33 f± 4m, having respective ages of 1788 ± 388 and 2914 ± 471 yr, imply a slip rate of 12.1 ± 2.6 mm/yr. The full range of ages obtained ((less than or equal to) 22.8 k.y., most of them between 6.7 and 1.4 k.y.) confirm that terrace deposition and incision, hence landform evolution, are modulated by post-glacial climate change. Coupled with minimum offsets of 9-12 m, this slip rate implies that great earthquakes (M-8) with a recurrence time of 800-1000 yr. rupture the Kunlun fault n
Date: September 1, 1998
Creator: Guoguang, Z; Caffee, M; Finkel, R; G demer, Y; Meriaux, A S; Qunlu, et al.
Partner: UNT Libraries Government Documents Department

HEU age determination

Description: A criteria that a sample of highly enriched uranium (HEU) had come from a weapons stockpile and not newly produced in an enrichment plant is to show that the HEU had been produced a significant time in the past. The time since the HEU has produced in an enrichment plant is defined as the age of the HEU in this paper. The HEU age is determined by measuring quantitatively the daughter products {sup 230}Th and {sup 231}Pa of {sup 234}U and {sup 235}U, respectively, by first chemical separation of the thorium and protactinium and then conducting alpha spectrometry of the daughter products.
Date: December 31, 1994
Creator: Moorthy, A.R. & Kato, W.Y.
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report: October 1 - December 31, 2010

Description: Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: March 2, 2011
Creator: Sisterson, DL
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report January 1–March 31, 2011

Description: Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Data Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Data Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: April 11, 2011
Creator: Sisterson, DL
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report October 1–December 31, 2011

Description: Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: January 9, 2012
Creator: Voyles, JW
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Climate Research Facility Operations Quarterly Report July 1–September 30, 2011

Description: Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: October 10, 2011
Creator: Voyles, J. W.
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1–June 30, 2011

Description: Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of processed data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: July 25, 2011
Creator: Voyles, JW
Partner: UNT Libraries Government Documents Department

Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

Description: We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.
Date: January 13, 2006
Creator: der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F & M?riaux, A
Partner: UNT Libraries Government Documents Department

Ancient and Modern Laminated Composites - From the Great Pyramid of Gizeh to Y2K

Description: Laminated metal composites have been cited in antiquity; for example, a steel laminate that may date as far back as 2750 B.C., was found in the Great Pyramid in Gizeh in 1837. A laminated shield containing bronze, tin, and gold layers, is described in detail by Homer. Well-known examples of steel laminates, such as an Adze blade, dating to 400 B.C. can be found in the literature. The Japanese sword is a laminated composite at several different levels and Merovingian blades were composed of laminated steels. Other examples are also available, including composites from China, Thailand, Indonesia, Germany, Britain, Belgium, France, and Persia. The concept of lamination to provide improved properties has also found expression in modern materials. Of particular interest is the development of laminates including high carbon and low carbon layers. These materials have unusual properties that are of engineering interest; they are similar to ancient welded Damascus steels. The manufacture of collectable knives, labeled ''welded Damascus'', has also been a focus of contemporary knifemakers. Additionally, in the Former Soviet Union, laminated composite designs have been used in engineering applications. Each of the above areas will be briefly reviewed, and some of the metallurgical principles will be described that underlie improvement in properties by lamination. Where appropriate, links are made between these property improvements and those that may have been present in ancient artifacts.
Date: March 14, 2000
Creator: Wadsworth, J. & Lesuer, D.R.
Partner: UNT Libraries Government Documents Department

Elliptical galaxies in high-z clusters: how old are they?

Description: I review recent research on the evolution of elliptical galaxies in high redshift galaxy clusters. Significant progress is being made on many fronts using the powerful tools of e.g. HST and 10 m class telescopes. But determining the actual age of composite stellar populations in distant galaxies is still beyond our capabilities.
Date: June 1, 1998
Creator: Stanford, S.A.
Partner: UNT Libraries Government Documents Department

14C dating of bone using (gamma) Carboxyglutamic Acid and Carboxyglycine (Aminomalonate)

Description: Radiocarbon determinations have been obtained on {gamma}-carboxyglutamic acid [Gla] and {alpha}-carboxyglycine (aminomalonate) [Am] as well as acid- and base-hydrolyzed total amino acids isolated from a series of fossil bones. As far as they are aware, Am has not been reported previously in fossil bone and neither Gla nor Am {sup 14}C values have been measured previously. Interest in Gla, an amino acid found in the non-collagen proteins osteocalcin and matrix Gla-protein (MGP), proceeds from the suggestion that it may be preferentially retained and more resistant to diagenetic contamination affecting {sup 14}C values in bones exhibiting low and trace amounts of collagen. The data do not support these suggestions. The suite of bones examined showed a general tendency for total amino acid and Gla concentrations to decrease in concert. Even for bones retaining significant amounts of collagen, Gla (and Am extracts) can yield {sup 14}C values discordant with their expected age and with {sup 14}C values obtained on total amino-acid fractions isolated from the same bone sample.
Date: April 27, 1999
Creator: Southon, J R; Burky, R T; Kirner, D L; Taylor, R E & Hare, P E
Partner: UNT Libraries Government Documents Department

Chinguetti - terrestrial age and pre-atmospheric size

Description: Chinguetti is a 4.5 kg mesosiderite find recovered from the Adra region of Mauretania. In this paper the authors analyse a portion of the recovered sample for cosmogenic radionuclides to determine its terrestrial age, and to determine its pre-atmospheric radius. They determined the terrestrial age of Chinguetti to be &lt; 30 ky. They constrain the pre-atmospheric radius to 50--80 cm and the shielding depths of 15--25 cm. These data indicate that Chinguetti is a comparatively recent fall.
Date: January 14, 2000
Creator: Welten, K C; Masarik, J; Bland, P A; Caffee, M W; Russell, S S; Grady, M M et al.
Partner: UNT Libraries Government Documents Department

The Potential for Dating Groundwater Using Radiogenic Noble Gases

Description: The accumulation in groundwater of products from the radioactive decay of elements naturally found in rocks offers a potential for measuring the time that the groundwater has been contact with the rock. This dating method has an advantage over using decay products from the atmosphere in that the amount of decay products increases with age rather than decreases. However, different decay products accumulate at different rates and, thus, have a different potential usefulness in age determinations. The most useful decay product is helium, produced from uranium and thorium. The use of Ar-40 produced from potassium is limited because Ar-40 is abundant in meteoric water. Neon, xenon and krypton are useful with great difficulty because they are produced in extremely small quantities. In general, the potential for error increases when a long time is required to produce a small quantity of the dating nuclide.
Date: March 23, 2001
Creator: Cornman, W.R.
Partner: UNT Libraries Government Documents Department

The Potential Use of Radioactive Decay Products for Dating Groundwater

Description: The accumulation in groundwater of products from the radioactive decay of elements naturally found in rocks offers a potential for measuring the time that the groundwater has been contact with the rock. This method of dating groundwater has an advantage over using decay products from the atmosphere in that the amount of decay product becomes greater with increasing age rather than less. However, different decay products accumulate at different rates and, thus, have a different potential usefulness in age determinations. The most useful decay product is helium, produced from uranium and thorium. Argon produced from potassium is marginally useful for very old water. Neon, xenon and krypton are probably not useful because they are produced in extremely small quantities. In general, the potential for error increases when a long time to produce a small quantity is required.
Date: March 20, 1980
Creator: Cornman, W.R.
Partner: UNT Libraries Government Documents Department

Age of the Harrison Street Beast: Electron paramagnetic resonance spectra from tooth enamel

Description: Workers doing road reconstruction in 1993 in Fort Wayne, Indiana, uncovered remains of a large skeleton and contacted archaeologists for assessment prior to continuing work. The archaeologists excavated the remains which were located in a 19-cm thick layer of blue glay, a pedological deposit which forms from wet, anaerobic environments associated with bogs. This glay layer was located some 2 meters below the current ground level (Davenport 1996). In this paper, the authors present the results of an EPR analysis of tooth enamel (biogenic hydroxyapatite) from the Harrison Street Beast. The objectives of this study are: (1) determine an age for the specimen through EPR analysis of molar tooth enamel; (2) resolve and identify the radiation sensitive EPR spectral components; and (3) develop a provisional model for the creation of radiation-sensitive components in the EPR spectra.
Date: April 1, 1998
Creator: Weeks, R.A.; Elam, J.M.; Davenport, C. & Bogard, J.S.
Partner: UNT Libraries Government Documents Department

Characterization of Quaternary and suspected Quaternary faults, regional studies, Nevada and California

Description: This report presents the results of geologic studies that help define the Quaternary history of selected faults in the region around Yucca Mountain, Nevada. These results are relevant to the seismic-design basis of a potential nuclear waste repository at Yucca Mountain. The relevancy is based, in part, on a need for additional geologic data that became apparent in ongoing studies that resulted in the identification of 51 relevant and potentially relevant individual and compound faults and fault zones in the 100-km-radius region around the Yucca Mountain site. Geologic data used to characterize the regional faults and fault zones as relevant or potentially relevant seismic sources includes age and displacement information, maximum fault lengths, and minimum distances between the fault and the Yucca Mountain site. For many of the regional faults, no paleoseismic field studies have previously been conducted, and age and displacement data are sparse to nonexistent. In November 1994, the Branch of Earthquake and Landslide Hazards entered into two Memoranda of Agreement with the Yucca Mountain Project Branch to conduct field reconnaissance, analysis, and interpretation of six relevant and six potentially relevant regional faults. This report describes the results of study of those faults exclusive of those in the Pahrump-Stewart Valley-Ash Meadows-Amargosa Valley areas. We also include results of a cursory study of faults on the west flank of the Specter Range and in the northern part of the Last Chance Range. A four-phase strategy was implemented for the field study.
Date: December 31, 1995
Creator: Anderson, R.E.; Bucknam, R.C.; Crone, A.J.; Haller, K.M.; Machette, M.N.; Personius, S.F. et al.
Partner: UNT Libraries Government Documents Department

Reactive Multiphase Behavior of CO2 in Saline Aquifers Beneath the Colorado Plateau

Description: Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. Efforts have focused on the Farnham Dome field, located in central Utah, and the Springerville-St. Johns field in Arizona and New Mexico. The Springerville-St. Johns field is particularly significant because of the presence of extensive travertine deposits that document release of CO{sub 2} to the atmosphere. CO{sub 2} accumulations at both fields occur in sedimentary rocks typical of CO{sub 2} reservoirs occurring on the Colorado Plateau. The main achievements during this quarter were: (1) a soil gas flux survey at the Springerville-St Johns field, (2) collection of some soil gas for chemical and isotopic analysis from this field, and (3) collection of travertine samples from an elevation range of over 1000 feet (330 m) for dating the time span of carbonate-saturated spring outflow at this field. Analytical results and interpretations are still in progress. When available they will allow contrast with soil gas measurements from Farnham Dome natural CO{sub 2} field in central Utah, which were reported in the previous quarterly report.
Date: October 21, 2003
Creator: Allis, R. G.; Moore, J. & White, S.
Partner: UNT Libraries Government Documents Department

ENHANCED PRACTICAL PHOTOSYNTHETIC CO{sub 2} MITIGATION

Description: This quarterly report documents significant achievements in the Enhanced Practical Photosynthetic CO{sub 2} Mitigation project during the period from 1/2/2004 through 4/1/2004. Specific results and accomplishments for the first quarter of 2004 include: (1) CRF-2 test system: After the recent successful test results were achieved, the system was taken off-line for re-sealing and other operational improvements to prepare for the next level of testing, which will include direct measurement of carbon uptake in addition to organism mass measurements. (2) 15 biomass slurry samples are currently being analyzed with carbon dating techniques at Galbraith Labs, and statistical analysis of the results will determine if pre and post test carbon analysis is an acceptable means for carbon uptake estimation. (3) Pilot Scale: Quantitative organism growth testing is underway in the pilot scale bioreactor. Problems with uniformity of organism loading delayed the start of quantitative testing, and it remains as a continuing issue that has not been completely resolved. (4) The sustainability test was begun with approximately 30 gallons of algae and 2 Omnisil membranes. The initial mass determination procedure was completed, and the biomass growth over the course of the experiment has been preliminarily quantified.
Date: April 15, 2004
Creator: Kremer, Gregory; Bayless, David J.; Vis, Morgan; Prudich, Michael; Cooksey, Keith & Muhs, Jeff
Partner: UNT Libraries Government Documents Department

Development and Application of a Paleomagnetic/Geochemical Method for Constraining the Timing of Burial Diagenetic Events

Description: Studies of diagenesis caused by fluid migration or other events are commonly hindered by a lack of temporal control. Our results to date demonstrate that a paleomagnetic/geochemical approach can be used to date fluid migration as well as burial diagenetic events. Our principal working hypothesis is that burial diagenetic processes (e.g., maturation of organic-rich sediments and clay diagenesis) and the migration of fluids can trigger the authigenesis of magnetic mineral phases. The ages of these events can be constrained by comparing chemical remanent magnetizations (CRMs) to independently established Apparent Polar Wander Paths. Whilst geochemical (e.g. stable isotope and organic analyses) and petrographic studies provide important clues for establishing these relationships, the ultimate test of this hypothesis requires the application of independent dating methods to verify the paleomagnetic ages. Towards this end, we have used K-Ar dating of illitization as an alternative method for constraining the ages of magnetic mineral phases in our field areas. We have made significant progress toward understanding the origin and timing of chemical remagnetization related to burial diagenetic processes. For example, a recently completed field study documents a relationship between remagnetization and the maturation of organic matter (Blumstein et al., 2004). We have tested the hypothesized connection between clay diagenesis and remagnetization by conducting K-Ar dating of authigenic illites in units in Scotland and Montana with CRMs (e.g., Elliott et al., 2006a; Elliott et al., 2006b). We have also developed a fluid related model for alteration and remagnetization of Appalachian red beds that involves reduction and mobilization of iron phases by hydrocarbons and precipitation of authigenic hematite as a result of the introduction of meteoric fluid recharge (Cox et al., 2005). In addition, our recent studies of fluid-related CRMs along faults in Scotland provide information on the timing and origin of fluid flow events along the ...
Date: January 5, 2006
Creator: Elmore, Richard D. & Engel, Michael H.
Partner: UNT Libraries Government Documents Department

Bacteria in Permafrost

Description: Significant numbers of viable ancient microorganisms are known to be present within the permafrost. They have been isolated in both polar regions from the cores up to 400 m deep and ground temperatures of -27 C. The age of the cells corresponds to the longevity of the permanently frozen state of the soils, with the oldest cells dating back to {approx}3 million years in the Arctic, and {approx}5 million years in the Antarctic. They are the only life forms known to have retained viability over geological time. Thawing of the permafrost renews their physiological activity and exposes ancient life to modern ecosystems. Thus, the permafrost represents a stable and unique physicochemical complex, which maintains life incomparably longer than any other known habitats. If we take into account the depth of the permafrost layers, it is easy to conclude that they contain a total microbial biomass many times higher than that of the soil cover. This great mass of viable matter is peculiar to permafrost only.
Date: January 1, 2008
Creator: Gilichinsky, David A.; Vishnivetskaya, Tatiana A.; Petrova, Maya A.; Spirina, Elena V.; Mamikin, Vladimir & Rivkina, Elizaveta
Partner: UNT Libraries Government Documents Department

Histological age estimation of the midshaft clavicle using a new digital technique.

Description: Histological methods to estimate skeletal age at death, in forensic cases, are an alternative to the more traditional gross morphological methods. Most histological methods utilize counts of bone type within a given field for their estimation. The method presented in this paper uses the percentage area occupied by unremodeled bone to estimate age. The percentage area occupied by unremodeled bone is used in a linear regression model to predict skeletal age at death. Additionally, this method uses digital software to measure area rather than the traditional technique in which a gridded microscope is used to estimate area. The clavicle was chosen as a sample site since it is not a weight bearing bone and has little muscular insertion. These factors reduce the variation seen as a result of differences in lifestyle or activity pattern.
Date: August 2004
Creator: Ingraham, Mark R.
Partner: UNT Libraries

Decreasing Cloudiness Over China: An Updated Analysis Examining Additional Variables

Description: As preparation of the IPCC's Third Assessment Report takes place, one of the many observed climate variables of key interest is cloud amount. For several nations of the world, there exist records of surface-observed cloud amount dating back to the middle of the 20th Century or earlier, offering valuable information on variations and trends. Studies using such databases include Sun and Groisman (1999) and Kaiser and Razuvaev (1995) for the former Soviet Union, Angel1 et al. (1984) for the United States, Henderson-Sellers (1986) for Europe, Jones and Henderson-Sellers (1992) for Australia, and Kaiser (1998) for China. The findings of Kaiser (1998) differ from the other studies in that much of China appears to have experienced decreased cloudiness over recent decades (1954-1994), whereas the other land regions for the most part show evidence of increasing cloud cover. This paper expands on Kaiser (1998) by analyzing trends in additional meteorological variables for Chi na [station pressure (p), water vapor pressure (e), and relative humidity (rh)] and extending the total cloud amount (N) analysis an additional two years (through 1996).
Date: January 14, 2000
Creator: Kaiser, D.P.
Partner: UNT Libraries Government Documents Department