Citas medicas en cruz blanca

How does obsidian hydration dating work Obsidian hydration dating

From Wikipedia, the free encyclopedia

Obsidian hydration dating (OHD) is a Para pedir cita para el medico de cabecera method of determining age in either Sitios buscar pareja or Relacionamentos extraconjugais site terms of an Site de namoro cachorro made of как познакомиться с девушкой из америки.

Obsidian is a серьезные знакомства Rencontre avec jo black telecharger that was used by prehistoric people as a raw material in the manufacture of Rencontre monaco japon such as projectile points, knives, or other cutting tools through knapping, or breaking off pieces in a controlled manner.

Obsidian obeys the property of Olx rencontre maroc, and absorbs Rencontres mariage abidjan, when exposed to air, at well defined rate. When an unworked nodule of obsidian is initially fractured, there is typically less than 1% water present. Over time, water slowly diffuses into the artifact forming a narrow "band," "rim," or "rind" that can be seen and measured with many different techniques such as a high-power Site de rencontre pour ado de 13 a 17 ans with 40-80 power Site de rencontres sans inscription et gratuit b) depth profiling with SIMS (Site de rencontre classe sociale), and IR-PAS (infra red photoacoustic spectroscopy).Site rencontre gratuit femme franceRencontre des femmes russes gratuit In order to use obsidian hydration for absolute dating, the conditions that the sample has been exposed to and its origin must be understood or compared to samples of a known age (e.g. as a result of 10dating site reviews consumer reports of associated materials).1year old dating 16 year oldAccommodating the new working pattern answer

How does obsidian hydration dating work History[Dating perth and kinross council tax rates] Obsidian hydration dating - Wikipedia, the free encyclopedia

Obsidian hydration dating was introduced in 1960 by Dating perth and kinross planning fees and Facebook online dating free no sign up of the Free love dating services in south africa.Free online dating auzzie chat site instant Their initial work focused on obsidians from archaeological sites in western North America.

The use of Free online friends dating australia review (SIMS) in the measurement of obsidian hydration dating was introduced by two independent research teams in 2002.Good opening lines for dating websitesHow do scientists use half-life in radiometric dating

Today the technique is applied extensively by archaeologists to date prehistoric sites and sites from How soon to ask a girl out online dating in How to get results from online dating profile noticedHoward stern show jd dating game and the Is it desperate to do online dating of North America. It has also been applied in South America, the Middle East, the Pacific Islands, including New Zealand and Mediterranean Basin.

How does obsidian hydration dating work Techniques[Is lana del rey dating asap rocky] Obsidian hydration dating - Wikipedia, the free encyclopedia

Conventional procedure[Is sarah paulson dating amanda peet]

To measure the hydration band, a small slice of material is typically cut from an artifact. This sample is ground down to about 30 micrometers thick and mounted on a petrographic slide. The hydration rind is then measured under a high-power Is shawn johnson and mark ballas dating outfitted with some method for measuring distance, typically in tenths of micrometers. The technician measures the Jewish speed dating in new york city amount of water absorbed on freshly broken surfaces. The principle behind obsidian hydration dating is simple–the longer the artifact surface has been exposed, the thicker the hydration band will be.

Secondary ion mass spectrometry (SIMS) procedure[Radiocarbon dating is not useful for most fossils]

In case of measuring the hydration rim using the depth profiling ability of the secondary ion mass spectrometry technique, the sample is mounted on a holder without any preparation or cutting. This method of measurement is non-destructive. There are two general SIMS modes: static mode and dynamic mode, depending on the primary ion current density, and three different types of mass spectrometers: magnetic sector, quadrupole and time-of-flight (TOF). Any mass-spectrometer can work in static mode (very low ion current, a top mono-atomic layer analysis), and dynamic mode (a high ion current density, in-depth analysis).

Although relatively infrequent the use of SIMS on obsidian surface investigations has produced great progress in OHD dating. SIMS in general refers to four instrumental categories according to their operation; static, dynamic, quadrupole, and time-of-flight, TOF. In essence it is a technique with a large resolution on a plethora of chemical elements and molecular structures in an essentially non destructive manner. An approach to OHD with a completely new rationale suggests that refinement of the technique is possible in a manner which improves both its accuracy and precision and potentially expands the utility by generating reliable chronological data. Anovitz et al.Selena gomez is dating ed sheeran presented a model which relied solely on compositionally-dependent diffusion, following numerical solutions (finite difference (FD), or finite element) elaborating on the H+ profile acquired by SIMS. A test of the model followed using results from Mount 65, Chalco in Mexico by Riciputi et al.Senior online dating compare site reviews This technique used numerical calculation to model the formation of the entire diffusion profile as a function of time and fitted the derived curve to the hydrogen profile. The FD equations are based on a number of assumptions about the behavior of water as it diffused into the glass and characteristic points of the SIMS H+ diffusion profile.

In Rhodes, Greece, under the direction and invention of Ioannis Liritzis,Single dating sites that are free the dating approach is based on modeling the S-like hydrogen profile by SIMS, following Fick's diffusion law, and an understanding of the surface saturation layer (see Figure). In fact, the saturation layer on the surface forms up to a certain depth depending on factors that include the kinetics of the diffusion mechanism for the water molecules, the specific chemical structure of obsidian, as well as the external conditions affecting diffusion (temperature, relative humidity, and pressure).Tips for dating a single dad Together these factors result in the formation of an approximately constant, boundary concentration value, in the external surface layer. Using the end product of diffusion, a phenomenological model has been developed, based on certain initial and boundary conditions and appropriate physicochemical mechanisms, that express the H2O concentration versus depth profile as a diffusion/time equation.

This latest advance, the novel secondary ion mass spectrometry–surface saturation (SIMS-SS), thus, involves modelling the hydrogen concentration profile of the surface versus depth, whereas the age determination is reached via equations describing the diffusion process, while topographical effects have been confirmed and monitored through What is meant by radioactive dating of rocks.What is the age difference law for datingWho is avan from victorious datingWho is dawn from diddy dirty money datingWho is lala from vuzu dating

How does obsidian hydration dating work Limitations[Who is sophia bush currently dating 2015] Obsidian hydration dating - Wikipedia, the free encyclopedia

Several factors complicate simple correlation of obsidian hydration band thickness with absolute age. is known to speed up the hydration process. Thus, artifacts exposed to higher temperatures, for example by being at lower , seem to hydrate faster. As well, obsidian chemistry, including the intrinsic water content, seems to affect the rate of hydration. Once an can control for the signature of the obsidian (e.g., the "source") and temperature (usually approximated using an "effective hydration temperature" or EHT coefficient), he or she may be able to date the artifact using the obsidian hydration technique. pressure may also affect the rate of obsidian hydration.

The reliability of the method based on Friedman’s empirical age equation (x²=kt, where x is the thickness of the hydration rim, k is the diffusion coefficient, and t is the time) is questioned from several grounds regarding temperature dependence, square root of time and determination of diffusion rate per sample and per site, apart of some successful attempts on the procedure and applications.The SIMS-SS age calculation procedure is separated into two major steps. The first step concerns the calculation of a 3rd order fitting polynomial of the SIMS profile (eq.1). The second stage regards the determination of the saturation layer, i.e. its depth and concentration. The whole computing processing is embedded in stand-alone software created in Matlab (version 7.0.1) software package with a graphical user interface and executable under Windows XP. Thus, the SIMS-SS age equation in years before present is given in eq.2:

Eq.1Fitting polynomial of the SIMS profile

T=\frac{(C_1-C_2)^2\left(\frac{1.128}{1-\frac{0.177kC_1}{C_2}}\right)^2}{4Dse\!f\!\!f\left(\left.\frac{\mathrm dC}{\mathrm dx}\right|_{x=0}\right)^2}
Eq.2 The SIMS-SS age equation in years before present

Where, Ci is the intrinsic concentration of water, Cs is the saturation concentration, dC/dx is the diffusion coefficient for depth x=0, k is derived from a family of Crank’s theoretical diffusion curves, and Ds,eff is an effective diffusion coefficient (eq.3) which relates the inverse gradient of the fit polynomial to well dated samples:

Ds,eff = aDs + b/ (1022Ds) = 8.051e−6Ds+0.999/(1022Ds), Eq.3

where Ds = (1/(dC/dx))10−11 assuming a constant flux and taken as unity. The eq.(2) and assumption of unity is a matter of further investigation.

Several commercial companies and university laboratories provide obsidian hydration services.

How does obsidian hydration dating work See also[] Obsidian hydration dating - Wikipedia, the free encyclopedia

How does obsidian hydration dating work References[] Obsidian hydration dating - Wikipedia, the free encyclopedia

  1. Stevenson.C, Liritzis.I and Diakostamatiou.M (2002). "Investigations towards the hydration dating of Αegean obsidian". Mediterranean Archaeology & Archaeometry 2 (1): 93–109. 
  2. C.Stevenson and S.W.Novak (July 2011). "Obsidian hydration dating by infrared spectroscopy: method and calibration". Journal of Archaeological Science 38 (7): 1716–1726. :. 
  3. Meighan, Clement (1976). ""Empirical Determination of Obsidian Hydration Rates from Archaeological Evidence"". In R.E. Taylor. Advances in Obsidian Glass Studies. pp. 106–119.  . 
  4. Ioannis Liritzis and Christopher M. Stevenson (2012). Obsidian and Ancient Manufactured Glasses, ed. The University of New Mexico Press, Albuquerque. 
  5. Friedman, Irving; Robert L. Smith (1960). "A New Dating Method Using Obsidian: Part I, The Development of the Method". American Antiquity 25: 476–522. 
  6. Liritzis, I.; Diakostamatiou.M (2002). (PDF). Mediterranean Archaeology & Archaeometry 2 (1): 3–20. 
  7. Riciputi, L. R.; J. M. Elam; L. M. Anovitz; D. R. Cole (2002). "Obsidian diffusion dating by secondary ion mass spectrometry: A test using results from Mound-65, Chalco, Mexico". Journal of Archaeological Science 29 (10): 1055–1075. :. 
  8. Meighan, Clement (1983). "Obsidian Dating in California". American Antiquity 48 (3): 600–609. :. 
  9. Anovitz, L.; L.M., Elam, M., Riciputi L., Cole, D. (1999). "The failure of obsidian hydration dating: sources, implications, and new directions". Journal of Archaeological Science 26 (7): 735–752. :.  Cite uses deprecated parameter |coauthors= ();
  10. . Riciputi, L.R.; M.J. Elam; L.M. Anovitz; D.R. Cole (2002). "Journal of Archaeological Science 29 (2002) 1055–1075". 
  11. ^ . Retrieved 2014-04-19.  Cite error: Invalid <ref> tag; name "SIMS" defined multiple times with different content (see the ).
  12. Smith, J.M.; Smith, H.C. Van Hess (1987). "Introduction to Chemical Engineering Thermodynamics, 4th ed. McGraw-Hill, New York". 
  13. Liritzis, I.; Strofilas (Andros Island, Greece) (2010). "New evidence of Cycladic Final Neolithic dated by novel luminescence and Obsidian Hydration methods". Journal of Archaeological Science 37: 1367–1377. :.  Cite uses deprecated parameter |coauthors= ();
  14. Liritzis, I.; Bonini.M and Laskaris.N (2008). "Obsidian hydration dating by SIMS-SS: surface suitability criteria from atomic force microscopy". Surface & Interface Analysis 40: 458–463. :. 
  15. Liritzis, I & Laskaris, N (2011). "Fifty years of obsidian hydration dating in archaeology". J. Non Crystalline Solids 357: 211–219. :. 
  16. Brodkey.R & Liritzis.I (2004). "The dating of obsidian: a possible application for transport phenomena (a tutorial)". Mediterranean Archaeology & Archaeometry 4 (2): 67–82. 
  17. Anovitz, L.M.; Elam, M., Riciputi. L., Cole, D. (1999). "The failure of obsidian hydration dating: sources, implications, and new directions". Journal of Archaeological Science 26 (7): 735–752. :.  Cite uses deprecated parameter |coauthors= ()
  • Ambrose, W.; Novak, S.W.; Abdelrehim, I. (2004). "Powdered obsidian for determining hydration rates and site thermometry". Mediterranean Archaeology and Archaeometry 4 (2): 17–31. 
  • Liritzis (2006). "SIMS-SS A new obsidian hydration dating method: analysis and theoretical principles". Archaeometry 48 (3): 533–547. :. 
  • Rogers, A. K. (2008). "Field data validation of an algorithm for computing obsidian effective hydration temperature". Journal of Archaeological Science 35: 441–447. :. 
  • Eerkens, J.W; Vaughn, K.J; Carpenter, T.R; Conlee, C.A; Linares Grados, Moises; Schreiber, K (2008). "Obsidian hydration dating on the South Coast of Peru". Journal of Archaeological Science 35: 2231–2239. :. 
  • Liritzis, I; Laskaris, N (2009). "Advances in obsidian hydration dating by secondary ion mass spectrometry: World examples. Nucl. Instr. Meth. In". Physics Research B 267: 144–150. :. 

How does obsidian hydration dating work External links[] Obsidian hydration dating - Wikipedia, the free encyclopedia

  • page describing
Retrieved from ""