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Two types of bell-shaped hyperbola, (a) normal bell shape and (b) reversed bell shape. For both the number of data points used for choosing appropriate polynomial fit is 265 and 251 respectively.
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Since 1960 the potential of obsidian as a chronometer in archaeology has been subjected to several drawbacks and studies. While economical, simple and fast, obsidian hydration dating today is generally unreliable. A novel approach towards obsidian hydration dating, named SIMS-SS, has recently been initiated based on modelling the hydrogen profile a...
Contexts in source publication
Context 1
... of this depth is made through use of the first derivative of a cubic spline fitting with the Savitzky-Golay algorithm. Subse- quently, the fitting with a 3rd order polynomial is determined from the beginning of the SIMS profile up to the inflection depth. This facilitates the location of the 1st derivative of the polynomial fitting (see inset of Fig. 1(a)). Following this, a new fit from the beginning of the profile until this 1st derivative peak with a new 3rd order polynomial is computed and a new derivative is found. This proce- dure continues until the very beginning of the SIMS profile or a derivative with no peak is reached. Then, repeated linear regres- sions are run from the last found derivative peak to the peak of the initial 1st derivative. It was noticed that the saturation layer lies always between these two peaks. This way the SS layer is defined much faster (an order of 30-60% in time elaboration) and more accurately compared to earlier sole use of the application of succes- sive linear regressions to the whole SIMS profile [8]. At the end of this procedure a bi-plot of the linear regressions slope versus data points clearly defines the saturation layer ( Fig. 1(b)). A further assessment concerns the calculation of the 3rd order polynomial modelling of the hydrogen profile, a most crucial parameter that requires accurate statistical procedures. Here, the initial data points caused by sputtering effects of the ion beam are removed, and the fitting is repeated by cutting and adding data points in the tail. Initially the whole tail is cut and the first 3rd or- der polynomial fitting is obtained on the remaining profile ( Fig. 2(a)). The tail end point and corresponding Rsqr of this fitting are recorded. Subsequently, successive single data points are added to the cut tail and the polynomial fitting is re-run. Following this the new Rsqr values are recorded. This procedure is repeated to the end of the tail (see, Fig. 2(b-d) with added depth points of 2.5-8 lm). In a few cases addition of extra points to the tail is made from the concentration value randomly selected from one of the last ten points of the flat section of C i . A plot of Rsqr versus data point number is constructed which forms a bell-shape curve (Fig. 3). This bell-shaped curve, occasionally with a local maximum ( Fig. 3(a)) or a local minimum (Fig. 3(b)), in fact, alludes to the suit- able polynomial needed for further processing. At any rate, the 3rd order polynomial fit at the curving bell's turn is the optimum poly- nomial, which is used to compute the diffusion rate and the ...
Context 2
... of this depth is made through use of the first derivative of a cubic spline fitting with the Savitzky-Golay algorithm. Subse- quently, the fitting with a 3rd order polynomial is determined from the beginning of the SIMS profile up to the inflection depth. This facilitates the location of the 1st derivative of the polynomial fitting (see inset of Fig. 1(a)). Following this, a new fit from the beginning of the profile until this 1st derivative peak with a new 3rd order polynomial is computed and a new derivative is found. This proce- dure continues until the very beginning of the SIMS profile or a derivative with no peak is reached. Then, repeated linear regres- sions are run from the last found derivative peak to the peak of the initial 1st derivative. It was noticed that the saturation layer lies always between these two peaks. This way the SS layer is defined much faster (an order of 30-60% in time elaboration) and more accurately compared to earlier sole use of the application of succes- sive linear regressions to the whole SIMS profile [8]. At the end of this procedure a bi-plot of the linear regressions slope versus data points clearly defines the saturation layer ( Fig. 1(b)). A further assessment concerns the calculation of the 3rd order polynomial modelling of the hydrogen profile, a most crucial parameter that requires accurate statistical procedures. Here, the initial data points caused by sputtering effects of the ion beam are removed, and the fitting is repeated by cutting and adding data points in the tail. Initially the whole tail is cut and the first 3rd or- der polynomial fitting is obtained on the remaining profile ( Fig. 2(a)). The tail end point and corresponding Rsqr of this fitting are recorded. Subsequently, successive single data points are added to the cut tail and the polynomial fitting is re-run. Following this the new Rsqr values are recorded. This procedure is repeated to the end of the tail (see, Fig. 2(b-d) with added depth points of 2.5-8 lm). In a few cases addition of extra points to the tail is made from the concentration value randomly selected from one of the last ten points of the flat section of C i . A plot of Rsqr versus data point number is constructed which forms a bell-shape curve (Fig. 3). This bell-shaped curve, occasionally with a local maximum ( Fig. 3(a)) or a local minimum (Fig. 3(b)), in fact, alludes to the suit- able polynomial needed for further processing. At any rate, the 3rd order polynomial fit at the curving bell's turn is the optimum poly- nomial, which is used to compute the diffusion rate and the ...
Context 3
... of this depth is made through use of the first derivative of a cubic spline fitting with the Savitzky-Golay algorithm. Subse- quently, the fitting with a 3rd order polynomial is determined from the beginning of the SIMS profile up to the inflection depth. This facilitates the location of the 1st derivative of the polynomial fitting (see inset of Fig. 1(a)). Following this, a new fit from the beginning of the profile until this 1st derivative peak with a new 3rd order polynomial is computed and a new derivative is found. This proce- dure continues until the very beginning of the SIMS profile or a derivative with no peak is reached. Then, repeated linear regres- sions are run from the last found derivative peak to the peak of the initial 1st derivative. It was noticed that the saturation layer lies always between these two peaks. This way the SS layer is defined much faster (an order of 30-60% in time elaboration) and more accurately compared to earlier sole use of the application of succes- sive linear regressions to the whole SIMS profile [8]. At the end of this procedure a bi-plot of the linear regressions slope versus data points clearly defines the saturation layer ( Fig. 1(b)). A further assessment concerns the calculation of the 3rd order polynomial modelling of the hydrogen profile, a most crucial parameter that requires accurate statistical procedures. Here, the initial data points caused by sputtering effects of the ion beam are removed, and the fitting is repeated by cutting and adding data points in the tail. Initially the whole tail is cut and the first 3rd or- der polynomial fitting is obtained on the remaining profile ( Fig. 2(a)). The tail end point and corresponding Rsqr of this fitting are recorded. Subsequently, successive single data points are added to the cut tail and the polynomial fitting is re-run. Following this the new Rsqr values are recorded. This procedure is repeated to the end of the tail (see, Fig. 2(b-d) with added depth points of 2.5-8 lm). In a few cases addition of extra points to the tail is made from the concentration value randomly selected from one of the last ten points of the flat section of C i . A plot of Rsqr versus data point number is constructed which forms a bell-shape curve (Fig. 3). This bell-shaped curve, occasionally with a local maximum ( Fig. 3(a)) or a local minimum (Fig. 3(b)), in fact, alludes to the suit- able polynomial needed for further processing. At any rate, the 3rd order polynomial fit at the curving bell's turn is the optimum poly- nomial, which is used to compute the diffusion rate and the ...
Citations
... δηά αυ κτ κυ υθ ζ ά παλΪΰ αδ απσ βθ τΰελδ β βμ εα α κηάμ κυ θ λκτ ( α δΪ α κ ΰλΪφβηα) η ηδα κηΪ α απσ α δΪ α μ γ πλβ δ-εΫμ εαηπτζ μ αθαφκλΪμ κυ Crank (Crank, 1975). Σ ζδεσ Ϊ δκ β ξλκθκζσΰβ β έθαδ β φαληκΰά σζπθ πθ πλκαθαφ λγΫθ πθ πα-λαηΫ λπθ (Xs εαδ Cs: υΰεΫθ λπ β εαδ ίΪγκμ εκλ ηκτ, Ci: θ κΰ θάμ υΰεΫθ λπ β θ λκτ, ek, D) βθ ιέ π β βζδεέαμ (Liritzis, 2006;Liritzis and Laskaris 2009). ...
... υ Ϊ α ίάηα α, πκυ π -λδζαηίΪθκθ αδ κ αθ έ κδξκ ζκΰδ ηδεσ (Liritzis et al., 2005), ια φαζέακυθ σ δ β υπκζκΰδαση θβ βζδεέα δθαδ απκζτ πμ α φαζάμ. Σσ κ α ελδ άλδα εα αζζβζσ β αμ σ κ εαδ α κξ υ ετλδα ίάηα α βμ η γσ κυ Ϋξκυθ φαληκ γ έ πΪθπ απσ κΰ σθ α έΰηα α απσ σζκ κθ εσ ηκ, πλκ λξση θα απσ δαφκλ δ-εΫμ πβΰΫμ κοδαθκτ εαδ ΰδα βζδεέ μ απκ 25 ξλσθδα Ϋπμ 30.000 ξλσθδα Π. τΰελδ β η δμ αλξαδκζκΰδεΪ αθαη θση θ μ βζδεέ μ Ϋξ δ απκ έι δ σ δ β ηΫγκ κμ έθαδ αιδσπδ β (Liritzis and Laskaris, 2009;Laskaris, 2010). ...
Research at the anonymous Cave of Schisto in Keratsini, Attica begun in 2006 and
continues in the form of a rescue excavation of the Ephorate of Palaeoanthropology – Speleology of the Greek Ministry of Culture. The cave served as a Sanctuary during Historical times, while its utilization extends up to Byzantine and even more recent years. In Prehistoric times, it was occupied during Late Neolithic I and II and also during Early Bronze Age II. Up until now, only a handful of shreds indicate that the cave was also used during the Middle Neolithic period. Of great importance are also the Upper Pleistocene/Early Holocen layers, according to the preliminary results of the typo-technological study of the lithic assemblages and the C14 dating.
The following article intends to put forward a wide field of discussion and interdisciplinary approaches about the rare discovery of obsidian artifacts in layers that predate the Neolithic, a find that has great implications in the study of early seafaring in the Aegean Sea. The samples were dated using the SIMS-SS obsidian hydration method, which proves to be currently the most credential obsidian dating technique worldwide.
... Where D s = (1/(dC/dx))*10 −11 assuming a scaling factor of constant flux taken as unity (Liritzis et al. 2005, Liritzis 2006, Liritzis and Laskaris 2009). In the calculation of D, the multiplication by 10 -11 has been performed in order to convert the units of D from the calculated μm 2 per 1000 years to cm 2 per year, which are the units used in SIMS-SS. ...
... As the Liritzis et alii proposed in previous works (Liritzis et al. 2008, Liritzis and Laskaris 2009, the SIMS-SS dating method incorporates a set of suitability criteria along with fixed steps in order to implement SIMS measurement, calculate the duration of the diffusion and, hence, determine the age of an artefact. ...
... First criterion: avoid roughness (Liritzis et al. 2008a, 2008b, Liritzis and Laskaris 2009) The surface roughness measured by the atomic force microscopy (AFM) is linearly correlated with the standard deviation of the residuals between the data points (H + values of gmole or atoms/cc) and the linear fit in the diffused region of SIMS (Liritzis et al., 2008). This correlation highlights the need for appropriate obsidian samples/surfaces selection (especially of the surface area/spot) for the SIMS analysis and therefore for the calculation of the age (Fig.6). ...
The dating of obsidian stone tools from the last time were in use by prehistoric man has been approached in 1960, by Friedman and Smith who observed that a freshly exposed surface of obsidian takes on ambient water at a knowable rate that can be used to calculate the time elapsed since exposure and, therefore, the date of an obsidian artifact's production. Subsequently the hydration procedure has been studied further and distinct versions of the so-called obsidian hydration dating (OHD) method has been developed proposing both empirical rate and intrinsic rate approaches. In the last 20 years, secondary ion mass spectroscopy (SIMS) has been employed to accurately define the hydration profile (water concentration versus depth) in a phenomenological manner. By modelling the hydration profile, the age determination is reached via models describing the diffusion process.
... A variety of different accuracy estimates are available for paleomagnetism [115][116][117][118]165] as well as for the specific application to archaeological materials known as archaeomagnetic dating [115][116][117][118]166]. Obsidian hydration is a useful technique for constructing coarse chronologies, especially of recent centuries [115][116][117][118][167][168][169][170], while it is possible to obtain satisfactory age past 30 000 years using secondary ion mass spectrometry surface saturation combined with mathematical techniques [169,171,172]. Dendrochronology has a number of subfields (e.g., dendroarchaeology, dendroclimatology, dendrovolcanology) and potentially excellent age accuracy at <2% [115][116][117][118]173], and a floating sequence has been constructed extending up to 13 900 years [174]. ...
Amino acid racemization, used as a method of relative and quantitative dating of fossils, evaluates the degree of postmortem conversion of l to d amino acid enantiomers. While extensively utilized, this method has garnered confusion due to controversial age estimates for human fossils in North America in the 1970s. This paper explains the age controversy and aftermath, current chromatographic methods used in research, mathematical calibration models, and a short synopsis of other dating techniques in geochronology and archaeometry.
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... Although these ages obtained follow criteria above the RHO-4 and YR-2 deviated from the linear tend of Fig. 7 due to different examined area. This issue resets the concern in choosing strictly appropriate area for SIMS and AFM for age calculation [30]. ...
Obsidian surface roughness and rind structure both play a major influence on the Obsidian Hydration Dating (OHD). AFM (Atomic Force Microscopy) investigation coupled with quadrupole SIMS hydrogen data profiles establish a validation criterion of quantitative evaluation of roughness for OHD dating purposes. More evidence of the importance of the surface morphology at the nanoscale is given for five obsidian tools of different origin. The latter relates to the dynamic ion influx diffusion kinetics between surface and surrounded sediment media, and the obsidian structure, thus, 2D and 3D surface mapping, as well as, cation profiling (H, C, Mg, Al, F, S, Cl, CN, O isotopes) were made by TOF-SIMS and quad-SIMS. It was found that the C and Mg are considered as imposed criteria for accepting suitability of H⁺ profiles for further processing by SIMS-Surface Saturation dating method. The effect of roughness to dating is discussed.
... One of the first major studies on this subject is a publication edited by Shackley (1998), which includes general information on obsidian, an overview of research methods, as well as a discussion on geochemical issues of these stones. Among the most common methods used in the study of obsidian are, first of all, those based on trace elements which are indicative in provenance analysis: XRF, PXRF, NAA, PIXE-PIGME, SEM-EDS, ICP-MS or LA-ICP-MS (Table 1.1; Bourdonnec at al. 2010;Duff et al. 2012;Liritzis and Laskaris 2009;Rogers 2008;Stevenson and Novak 2011). The presence and proportions of trace elements are very important indicators for determining the provenance of obsidian present at archaeological sites, e.g. in the form of tools. ...
... temperature, humidity, sunlight), it is not considered to be very reliable. In order to achieve more credible results, researchers use secondary ion mass spectrometry -surface saturation (SIMS-SS), where numerical calculations and analysis spectra that depend on the concentration of H + in the "profile" of the rocks have improved in recent years (Liritzis and Laskaris 2009;Rogers 2008;Stevenson and Novak 2011). ...
... The SIMS-SS method includes a wide range of suitability criteria and procedures that reduce the propagation of errors and maximize the efficiency of the method (Liritzis and Laskaris, 2009, 2011a, Laskaris, 2010Liritzis and Laskaris, 2011). These criteria along with the Taylor's error propagation statistics provide overall accuracy. ...
... These new procedures and criteria were tested with a comparison of SIMS-SS ages with independent methods for a wide variety of obsidian samples from all over the world (Liritzis et al., 2008a;Liritzis and Laskaris, 2009;Laskaris, 2010). The commensurability between the archaeological expected ages and the SIMS-SS ages is quite high and reinforces the validity and wide applicability of the novel dating approach (http://www.rhodes.aegean.gr/tms/ ...
... where D s = (1/(dC/dx)) × 10 − 11 assuming a constant flux and taken as unity [24,39,109]. Eq. (8) and assumption of unity is a matter of further investigation. ...
... The SIMS-SS age estimates fall within the expected age ranges for the archaeological contexts for all samples. [109,110]. ...
... The preferred analysis for such types of samples is with the aid of other imaging techniques. (e.g., AFM, PLM, and SEM) to guide a re-acquisition of the SIMS hydrogen profile, and hydrogen profiles are then grouped into acceptable and non-acceptable categories [109]. (Figs. 6 and 7). ...
About fifty years ago Friedman and Smith [1] recognized the obsidian hydration phenomenon and proposed an empirical dating method based on the conversion of the optically measured hydration depth to an absolute age. They and subsequent researchers developed distinct versions of obsidian hydration method consisting of both empirical rate and intrinsic rate development, thus refining the method. However, in spite the accurately measured rinds beyond digital optical microscopy employing infrared spectroscopy and nuclear analysis, the traditional empirical age equation produce occasionally satisfactory results but still fail to produce a reliable chronometer. In the last ten years, secondary ion mass spectrometry (SIMS) has been employed to accurately define the hydration profile. By modeling the profile of the surface hydrogen concentration versus depth the age determination is reached via equations describing the diffusion process. Finite difference modeling and essential assessments of the novel SIMS-SS (surface saturation) phenomenological method produce a sound basis for the new diffusion age equation and provides promising results. This review refers on the development of obsidian hydration dating (OHD) and diffusion process in glass and reckons future directions of SIMS applications in obsidians.Research Highlights► Fifty years of obsidian hydration dating in archaeology. ► Diffusion phenomena in obsidian. ► First report of the Obsidian hydration dating in 1960 by Friedman and Smith. ► New approaches of hydrated surface layer by using Fick's law of diffusion. ► New approach for measuring hydration layer with Secondary Ion Mass Spectrometry.
... The latter is reflected in slight variations of shapes of the sigmoid profiles between different obsidians and environments as has been shown elsewhere (Liritzis, 2006). Although the claim of being independent of environmental factors could be labelled an assertion, experience with a majority of obsidian sources from many parts of the World and age span over the past 30,000 years, so far, verifies steadily its validity (Liritzis and Laskaris, 2009). Moreover laboratory simulated hydration experiments running over 20 years seem to verify this assertion and provide correct ages (Liritzis et al., in preparation) We have evaluated a procedure for obsidian age estimation that is based upon the depth and shape of the H þ diffusion profile as determined by SIMS. ...
... This standard was used to calibrate the sputtering rate, so that there was no direct crater depth measurements of archaeological samples. The procedure was processed via a novel software (Liritzis and Ganetsos, 2006;Liritzis et al., 2008b;Liritzis and Laskaris, 2009). ...
... Table 3 gives the measured and calculated data of equation (3). Based on the criteria imposed for the suitability of samples from their sigmoid shapes and the involved respective error from surface topography (investigated by Atomic Force Microscopy) the Strofilas samples are suitable enough providing a satisfactory overall age error (Liritzis and Laskaris, 2009). Both pieces fall within the island of Melos sources, as Ti and Sr plotting alone have shown (Liritzis, 2008). ...
The recently excavated coastal prehistoric settlement of Strofilas on Andros Island (Cyclades, Greece) in the Aegean sheds new light on the transitional phase from the Final Neolithic to Early Cycladic period regarding masonry, fortification, and richly engraved rock art. The fortification possesses early evidence of preserved defensive architecture, as evidenced from the plethora of scattered finds from within and around the settlement. Important features are carvings on rock walls which mainly depict ships, animals, and fish. Initial archaeometric dating via the application of luminescence dating of two samples from the fortified wall bearing engraved ships, and by obsidian hydration of two blades employing the new SIMS-SS method (secondary ion mass spectrometry via surface saturation), has been undertaken to determine the site's chronology. The former yields an average date of 3520 (±540) BC and the latter an average date of 3400 (±200) years BC, both of which, within overlapping errors, suggest the main settlement occurred during the Final Neolithic.
... Therefore, obsidian is one of the most widely distributed natural glasses in the Aegean Region and could poten‐ tially constitute a powerful chronological tool for the study of regional archaeological sites. The recent progress in obsidian hydration dat‐ ing (Liritzis et al., 2007; Liritzis and Laskaris, 2009) and characterization (Liritzis, 2006) has gained an international interest; however, lu‐ minescence dating applications of obsidian are rarely reported in the literature (Göksu and Turetken, 1979). In the present work, prelimi‐ nary measurements regarding basic thermolu‐ minescence (TL) as well as optically stimulated luminescence (OSL) properties were obtained, using natural obsidian recovered from Melos, in order to evaluate its potential use in archaeo‐ logical dating and retrospective dosimetry. ...
Obsidian is a volcaniclastic mineral extremely hard to break, which was used in prehistoric Greece (and elsewhere in the World), in order to provide tools, weapons, knives and arrowheads. The present work aims to characterize this extremely precious tool stone by using both thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques and investigate its potential use for luminescence dating purposes. Basic TL and OSL properties, such as TL and OSL thermal and optical stability, repeatability, TL and LM-OSL glow curve shape and mainly the linearity of the TL and OSL signals as a function of beta dose were investigated. Artificially irradiated samples indicate all promising luminescence features, such as the 110 °C TL peak and dose response sub-linearity for intermediate doses, quick and effective bleaching all over the entire TL glow curve, along with quite linear CW-OSL dose response for doses larger than 5 Gy. The lack of predose sensitisationindicates the suitability of the material for single aliquot measurements. Furthermore, several features provide indications that the signal does not relate to quartz, but in fact to other silicates. Unfortunately, both lack of bleaching ability for NTL signal, along with a peculiar shape of NOSL, provide major difficulties in dating applications.
... Therefore, obsidian is one of the most widely distributed natural glasses in the Aegean Region and could potentially constitute a powerful chronological tool for the study of regional archaeological sites. The recent progress in obsidian hydration dating (Liritzis et al., 2007;Liritzis and Laskaris, 2009) and characterization (Liritzis, 2008) has gained an international interest; however, luminescence dating applications of obsidian are rarely reported in the literature (Göksu and Turetken, 1979). In the present work, preliminary measurements regarding basic thermoluminescence (TL) as well as optically stimulated luminescence (OSL) properties were obtained, using natural obsidian recovered from Melos, in order to evaluate its potential use in archaeological dating and retrospective dosimetry. ...
Obsidian is a volcaniclastic mineral extremely hard to break, which was
used in prehistoric Greece (and elsewhere in the World), in order to
provide tools, weapons, knives and arrowheads. The present work aims to
characterize this extremely precious tool stone by using both
thermoluminescence (TL) and optically stimulated luminescence (OSL)
techniques and investigate its potential use for luminescence dating
purposes. Basic TL and OSL properties, such as TL and OSL thermal and
optical stability, repeatability, TL and LM-OSL glow curve shape and
mainly the linearity of the TL and OSL signals as a function of beta
dose were investigated. Artificially irradiated samples indicate all
promising luminescence features, such as the 110 oC TL peak and dose
response sub-linearity for intermediate doses, quick and effective
bleaching all over the entire TL glow curve, along with quite linear
CW-OSL dose response for doses larger than 5 Gy. The lack of predose
sensitisation indicates the suitability of the material for single
aliquot measurements. Furthermore, several features provide indications
that the signal does not relate to quartz, but in fact to other
silicates. Unfortunately, both lack of bleaching ability for NTL signal,
along with a peculiar shape of NOSL, provide major difficulties in
dating applications.
