Recent arf_xrfreports items

XRF Analysis of samples from the Anillo Obsidian Source near Cotahuasi, Arequipa, Peru

Wed, 11 Feb 2026 00:00:00 +0000

This geochemistry report is a dynamic notebook hosted on Github at https://github.com/arf-berkeley/obsidian-source-anilloThe Anillo obsidian source lies to the north of the Cotahuasi Canyon in southern Peru. It is geochemically distinct from the better known Alca obsidian south on the south side of the Cotahuasi valley. This report shares the geochemical results of analysis with a Bruker Tracer 5g XRF.

New Pen & Old Ink: XRF Analysis of a Unique Archive from 1st c. BCE Tebtunis

Fri, 14 Apr 2023 00:00:00 +0000

This study examines the ink used in an archive of >50 bilingual papyri (in Greek and Demotic) written by a single scribe that were found in two crocodile mummies excavated from Tebtunis by B.P. Grenfell and A.S. Hunt in 1900.

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM LA 99414 AND LA 183311, SOUTHEASTERN NEW MEXICO

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 49 artifacts (48 obsidian) from two sites in southeastern New Mexico exhibits an obsidian provenance assemblage entirely from Jemez Mountains sources, one of which (Cerro Toledo Rhyolite, 79.2%) was most likely procured from Rio Grande Quaternary alluvium. Valles Rhyolite (Cerro del Medio) at 20.8% of total was probably not procured from Rio Grande Quaternary alluvium, but the primary source proper, according to available research (Church 2000; Shackley 2012).

ENERGY-DISPERSIVE X-RAY FLOURESCENCE (EDXRF) ANALYSIS OF MAJOR, MINOR AND TRACE ELEMENTS FOR ONE TURQUOISE GLOBULAR BEAD AND ONE OBSIDIAN ARTIFACT FROM SITE SRPMICH-62, ON THE SALT RIVER PIMA-MARICOPA INDIAN COMMUNITY, CENTRAL ARIZONA

Fri, 13 May 2022 00:00:00 +0000

The analysis here ofone obsidian flake and one turquoise bead indicates that the obsidian artifact was produced from the Vulture source west of the Phoenix Basin, commonly recovered in Preclassic Hohokam contexts in the Lower Salt River Valley (Shackley 2005, 2019; Table 1 herein). A short discussion of the turquoise bead is offered belowas well.

ENERGY-DISPERSIVE X-RAY FLOURESCENCE (EDXRF) WHOLE ROCK ANALYSIS OF MAJOR, MINOR AND TRACE ELEMENTS FOR OBSIDIAN AND OTHER VOLCANIC ROCK ARTIFACTS FROM THE EL SEGUNDO ARCHAEOLOGY PROJECT, NORTHWESTERN NEW MEXICO

Fri, 13 May 2022 00:00:00 +0000

The analysis here of a variety of artifacts from a number of sites or site groups in the El Segundo project area is dominated by obsidian sources along the Jemez Lineament, and a variety of rock types likely typical of the local geology. One piece of obsidian debitage was produced from the Government Mountain source in the San Francisco Volcanic Field or northern Arizona, over 370 linear km west. Government Mountain obsidian has occurred in El Segundo project sites and other Archaic contexts in the Grants, New Mexico area just south of El Segundo (Birkmann et al. 2018). One dacite projectile point base was produced from the San Antonio Mountain source in the Taos Plateau Volcanic field over 250 linear km north.

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM THE CROSSPATCH SITE SOUTHWEST COLORADO

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 71 artifacts (70 obsidian) from the Crosspatch site in southwestern Colorado indicates a very diverse obsidian provenance assemblage with artifacts produced from obsidian sources in northern and southwestern New Mexico, to northern Arizona, to southwestern Utah (Tables 1 and 2 and Figures 1 and 2). A short discussion of the results is offered below.

AN ENERGY.DISPERSIVE X.RAY FLUORESCENCE ANALYSIS OFOBSIDIAN ARTIFACTS FROM LA 1 87467 AND LA 190067, LORDSBURGMESA, SOUTHWESTERN NEI'V MEXIGO

Fri, 13 May 2022 00:00:00 +0000

All the artifacts were produced from two of the sources in the Mule Creek Obsidian Complex, Mogollon-Datil volcanic province, western New Mexico (Antelope Creek and Mule Mountains), although obsidian from these sources are also available as secondary deposits in San Francisco and Gila River Quaternary alluvium in eastern Arizona (Shackley 1992. 1998; Shackley et al. 2018; Table 1, Figure 1, and cover image herein). The cortex on sample #12 fnmLA 187467 appears to be typical of the secondary deposit obsidian in Gila River alluvium (Shackley 1992,1998).

ENERGY-DISPERSIVE X-RAY FLOURESCENCE (EDXRF) WHOLE ROCK ANALYSIS OF MAJOR, MINOR AND TRACE ELEMENTS FOR ARTIFACTS FROM THE EL SEGUNDO ARCHAEOLOGY PROJECT, NORTHWESTERN NEW MEXICO

Fri, 13 May 2022 00:00:00 +0000

The analysis here of a variety of artifacts from a number of sites or site groups in the ElSegundo project area is dominated by obsidian sources along the Jemez Lineament, and a variety of rock types likely typical of the local geology. These results are similar to previous studies of sites in the area, and support the provenance inferences from these studies (see Shackley 2015a, 2015b, 2016). None of the volcanic rocks determined to be dacite are from the three known sources in northern New Mexico (Shackley 2011a). At least two artifacts could be produced from the Black Canyon hydrothermally altered rhyolite near Socorro, New Mexico, but the variability at the source is so great, that confident inferences cannot be made at this time (Dello-Russo 2004; Table 1).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM ARCHAEOLOGICAL CONTEXTS IN THREE REGIONS OF SONORA, MEXICO

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 297 artifacts (292 obsidian, and a few not analyzed due to size) from three regions and a number of sites in the State of Sonora, Mexico indicates a very diverse provenance assemblage with known sources on both sides of the border, Chihuahua and Sonora, and a large proportion of, as yet, unlocated sources (58.2%) dominated by one source (44.2%) that is likely located somewhere along the Río Sonora or somewhere above that stream basin (see cover image and Figure 1). This is the largest, as yet, archaeological obsidian provenance study in Sonora, and despite the number of "unknown" sources provides a good basis for further archaeological and geoarchaeological research in Sonora.

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM A NUMBER OF SITES IN THE BIG BEND REGION OF SOUTHWEST TEXAS

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 55 obsidian artifacts from a number of sites in the Big Bend Region of southwest Texas indicates procurement of obsidian for tool production from sources in New Mexico, Chihuahua, and a significant as yet unlocated source possibly from the Big Bend region (TX Unknown A). This diverse provenance assemblage is dominated by Cerro Toledo Rhyolite obsidian, a Rio Grande secondary deposit source from northern New Mexico, Los Jagueyes a secondary source along the Rio Santa Maria in northeastern Chihuahua, Sierra Fresnal in the range by the same name, and Lago Fredrico, another source defined by only two source standards (Shackley 2005; see Figures 1 and 2 here). The number of as yet located primary sources in northwest Mexico and probably southwest Texas frustrates provenance studies in the region (cf Lintz et al. 2014; Hughes 2019). Included is a short discussion of the regional geology as relevant for geoarchaeological studies as well as a short description of...

SOURCE PROVENANCE OF GILA RIVER QUATERNARY ALLUVIAL OBSIDIAN AND OBSIDIAN ARTIFACT PROVENANCE FROM THE SANCEZ SITE (AZ CC:2:452 ASM), SOUTHEASTERN ARIZONA

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 38 Quaternary alluvial secondary deposit obsidian indicates a diverse source provenance dominated by obsidian from the upstream primary sources of the Cow Canyon Obsidian Complex, and eachof the three major localities at the Mule Creek Obsidian Complex in eastern New Mexico, all part of the Mogollon-Datil Volcanic Province(see cover image). All of these sourceshave been eroding into the Blue, San Francisco, and Gila River systems for over 21 Ma (Shackley 2018; Shackley et al. 2018). The surface and excavated obsidian artifact assemblage (n=16) from the Sanchez Site (AZ CC:2:452 ASM) is generally a reflection of the mix of sources in the Gila River alluvium with slightly less diversity, but still dominated by sources of the Cow Canyon Obsidian Complex.

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM TWO SITES IN PINAL COUNTY, ARIZONA

Fri, 13 May 2022 00:00:00 +0000

The analysis here of sixobsidianartifacts fromtwo Formative Period sites near Kelvin, Arizona along the Gila River indicates that all the artifacts were produced from the Superior (Picketpost Mountain) source approximately 25 linear kilometers north of the sites, and the nearest obsidian source (see cover image, Table 1 and Figure 1). Superior obsidian is also available as secondary deposits in Queen Creek Quaternary alluvium at least as far as Florence Junction (Shackley 1988, 1995, 2005).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM THREE EXCAVATED SITES FROM THE UNIVERSITY OF TEXAS, SAN ANTONIO 2016 FIELD SCHOOL PROJECT IN EASTERN ARIZONA

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 109 artifacts from three excavated sites from the University of Texas, San Antonio field school, indicates procurement of four of the regional obsidian sources from the Mogollon-Datil Volcanic Province in western New Mexico and eastern Arizona, a similar distribution to the surface collections from these and other sites in the project area (see Shackley 2015; Shackley et al. 2016a). The assemblage overall is dominated by obsidian from the Antelope Creek West locality at Mule Creek, New Mexico, followed by the North Sawmill Creek group, and two artifacts produced from the Mule Mountains source at Mule Creek. All of the four sources are present in San Francisco and Gila River Quaternary alluvium, but there are reasons to infer that at least some of the artifacts were produced from obsidian procured from the primary sources to the north and east (see discussion).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM FOUR ARCHAEOLOGICAL SITES IN SOUTHEASTER NNEW MEXICO

Fri, 13 May 2022 00:00:00 +0000

The source provenance of the artifacts is dominated by Jemez Mountains sources(Table 1and Figure1; see Shackley 2016). Cerro Toledo Rhyolite obsidianis available as secondary deposits in Rio Grande Quaternary alluviumat least to Las Cruces, but Valles Rhyolite (Cerro del Medio) has not been found south of Albuquerque, and only as a few small diameter samples(Church 2000; Shackley 2005, 2013, 2020).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM TWO SITES IN PINAL COUNTY, ARIZONA

Fri, 13 May 2022 00:00:00 +0000

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM FROM THE STEWARD SITE (41PT519), NORTH TEXAS

Fri, 13 May 2022 00:00:00 +0000

The analysis here of five obsidian artifacts from 41PT501 in north Texas indicates that all the artifacts were produced from the Cerro Toledo Rhyolite obsidian source in the Jemez Mountains of northern New Mexico (Table 1 and Figure 1). Cerro Toledo Rhyolite obsidian along with Valles Rhyolite (Cerro del Medio) obsidian was the most commonly procured from the Jemez Mountains sources (Shackley 2005; Shackley et al. 2016).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM ARCHAEOLOGICAL SITES IN THE EAST RANKIN VALLEY, BARRY M. GOLDWATER AIR FORCE RANGE, SOUTHWESTERN ARIZONA

Fri, 13 May 2022 00:00:00 +0000

The analysis here of 18 obsidian artifacts from various sites in the east Rankin Valley on the Barry Goldwater Air Force Range (BMGR) yields a source provenance typical of various periods on the range, dominated by one of the two chemical groups of Sauceda Mountains, with Los Vidrios, and Los Sitios del Agua present in the minority (Martynec et al. 2011; Shackley 2005, 2012, 2014; Shackley and Tucker 2001).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM SOUTHERN NEW MEXICO

Fri, 13 May 2022 00:00:00 +0000

Two of the artifacts are produced from Valles Rhyolite (Cerro del Medio) obsidian, and one was not obsidian (Table 1). Valles Rhyolite (Cerro del Medio) has not been recorded in any size or quantity in the alluvium, including Rio Grande southern New Mexico localities, so was likely originally procured in Valles Caldera proper (Church 2000; Shackley 2005, 2012).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM PINTO CANYON RANCH, SOUTHWESTERN TEXAS

Fri, 13 May 2022 00:00:00 +0000

The mix of sources is similar to the previous study (Shackley 2019) with the addition of sources to the west of the Sierra Madre ridgeline in Sonora (see Table 1 and Figure 1; Kibler et al. 2014; Shackley 2005). The TX Unknown A type is also present as well as Jemez Mountains obsidian most likely procured from Rio Grande Quaternary alluvium, and the two Chihuahuan source present in the previous study (Church 2000; Shackley 2012). The assignment to Lago Barreal is not confident with some elements outside the range of the source standards and that there are only eight source standards known from that source (Shackley 2005). See previous study for a more extensive discussion of sources and regional geology (Shackley 2019)

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM AZ AA:12:85 (ASM), CENTRAL, ARZIZONA

Fri, 13 May 2022 00:00:00 +0000

The one piece of obsidian debitage was produced from the Sand Tanks source located in western Maricopa County, Arizona (Shackley 2005, Shackley and Tucker 2001). This source is relatively uncommon in archaeological contexts, but has occurred in central Arizona sites (Shackley and Tucker 2001).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF AN OBSIDIAN BIFACE FROM SOUTHEASTERN UTAH

Fri, 13 May 2022 00:00:00 +0000

As we discussed, the obsidian biface was produced from the El Rechuelos Rhyolite obsidian source in the northern Jemez Mountains, northern New Mexico

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM THREE ARCHAEOLOGICAL SITES IN THE VALLE DE ALTAR, NORTHERN SONORA, MEXICO

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 300 artifacts (12 not obsidian and a few not analyzed) from three sites (SON:F:2:4, 61, and 82) in the Valle de Altar in the northern State of Sonora, Mexico indicates a very diverse provenance assemblage with known sources on both sides of the border, including Arizona, New Mexico, Chihuahua and Sonora, and a large proportion of, as yet, unlocated sources (73.9%) dominated by one unusual trachyte obsidian source (72.9%). The main unknown source is likely located somewhere along the Río Altar or somewhere above that stream basin, and called provisionally here SON Valle de Altar Unknown. The diversity of obsidian source provenance decreases from west to east as the unknown source dominates the assemblage (see cover image). This study is one of the largest archaeological obsidian provenance studies in Sonora, and despite the number of "unknown" sources provides a good basis for further archaeological and geoarchaeological research in Sonora (see also Shackley 2019a).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM THE CLASSIC PERIOD ROWLEY SITE (AZ U:9:49 ASU), MESA, ARIZONA

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 83obsidian bifaces (five were not obsidian or too burned/dirty to analyze) indicates an extremely diverse obsidian provenance assemblage with a mix of sources somewhat atypical for Classic contexts in the Middle Salt River Valley

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM PIEDRAS MARCADAS PUEBLO RUIN (LA 290), MIDDLE RIO GRANDE VALLEY, NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 195 obsidian artifacts from the surface and subsurface of Piedras Marcadas Pueblo ruin (LA 290) in the middle Rio Grande River valley indicates a source provenance similar to previous analyses of surface and subsurface contexts dominated by sources from the Jemez Mountains, both pre-and-post caldera, (Shackley 2009, 2013a, 2014a, 2014b). All these sources are present in the Rio Grande alluvium as far south as Albuquerque, although the Valles Rhyolite (Cerro del Medio) nodules are very small, probably too small to produce the one projectile point made from this source (Sample 1911; Shackley 2021). Mount Taylor is not available in Rio Grande Quaternary sediments this far north (Shackley 2021). Refer to Shackley (2021) for a thorough discussion of the sources and secondary distribution.

Most unique and important for the history of the site, and indeed the Coronado presence in the Middle Rio Grande valley is the occurrence of two polyhedral blade fragments...

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM LA 193369, SOUTHERN NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

The two obsidian debitage pieces are both produced from Valles Rhyolite (Cerro del Medio) obsidian in the Jemez Mountains, northern New Mexico (Table 1).

SOURCE PROVENANCE OF TWO OBSIDIAN ARTIFACTS FROM LAS TORTUGAS, GRAN DESIERTO, SONORA, MEXICO

Thu, 12 May 2022 00:00:00 +0000

The two artifacts from the Clovis site of Las Tortugas, Gran Desierto, northern Sonora are from one known and one as yet unlocated source: one piece of debitage from the Sauceda Mountains source in southwest Arizona, and one matching the composition of a single artifact recovered from the upper Rio Sonora in northern Sonora (Shackley 2005, 2019a). The biface, a possible Clovis fragment, produced from the source matching the one artifact from the Rio Sonora region is likely from a locality in northern Sonora, the location of which remains unknown. It does not match any known source in the Skinner/Shackley database of North American obsidian sources, including those in northwest Mexico (see Shackley 2005; Vidal-Solano et al. 2020; Table 1, Figures 1 and 2, see also cover image).

SOURCE PROVENANCE OF AN OBSIDIAN ARTIFACT AND X-RAY FLUORESCENCE (XRF) COMPOSITIONAL ANALYSIS OF A CERAMIC SHERD FROM LA 159019, EDDY COUNTY, SOUTHEASTERN, NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

Analyzed here is one obsidian artifact assigned to Valles Rhyolite (Cerro del Medio) from the Jemez Mountains in northern New Mexico and one ceramic sherd with a high alkaline composition (i.e. Na, Ca, K) that suggests a sedimentary origin rather than silicic (i.e. granitoid) residual clay origin (Table 1 and Figure 1; see discussion).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM LA 192236 and 192238, CATRON COUNTY, SOUTHERN NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

The four pieces of obsidian debitage are allproduced from the Red Hill obsidian source located within a radius of two km, essentially on site(Table 1; Figure 1). This source is actually a discontinuous Neogene remnant rhyolite dome complex that has been partly subsumed by Quaternary mafic volcanism, much of it fissure flows that have formed mesas as well as cinder cones such as Red Hill (see http://swxrflab.net/redhill.htm; Shackley 1995, 2005)

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM CRYSTAL CAVE (39LA504) WESTERN SOUTH DAKOTA

Thu, 12 May 2022 00:00:00 +0000

The results of the x-ray fluorescence analysis (XRF) here of 148 obsidian artifacts from Late Archaic contexts at Crystal Cave (39LA504), western South Dakota indicates procurement of three major prehistoric obsidian sources in western Wyoming (Obsidian Cliff) and eastern Idaho (Bear Gulch and Malad; see Tables 1 and 2 and Figures 1 and 2 here). These sources are common in Great Plains and Rocky Mountain sites (Hughes 2007; see discussion).

SOURCE PROVENANCE OF OBSIDIAN ARTIFACTS FROM ARMIJO SHELTER, CENTRAL NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 72 obsidian projectile points from Armijo Shelter (LA 9300) is dominated by the production of projectile ponts from obsidian sources along the Jemez Lineament, mainly sources from the Jemez Mountains (94.4%) north of the site, and one of the two Mount Taylor sources (Horace/La Jara Mesa) south of the project area (5.6%). Nearly 42% of the obsidian projectile points were produced from the Valles Rhyolite (Cerro del Medio) source in Valles Caldera in the Jemez Mountains.

AN ENERGY-DISPERSIVE X-RAY FLOURESCENCE (EDXRF) ANALYSIS OF OBSIDIAN AND VOLCANIC ROCK ARTIFACTS FROM A PRIVATE COLLECTION

Thu, 12 May 2022 00:00:00 +0000

The analysis here of a variety of artifacts from a private collection with unknown provenience indicates that some of the obsidian artifacts were produced from the Craine Creek source, Bog Hot Springs locality, in northwest Nevada (see Table 1, Figures 1 and 2). This source is not necessarily common even in Great Basin sites, and given this and that the remainder of the artifacts could not be assigned to source, suggests that at least some of the collection is from northern Nevada or southern Oregon

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM THREE SITES NEAR THE JUNCTION OF INTERSTATE HIGHWAY 40 AND NEW MEXICO STATE HIGHWAY 6, CENTRAL NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

As you suspected, the artifacts from these three sites were produced from one of the Mount Taylor sources, or one of the three major sources in the Jemez Mountains (Tables 1 and 2).

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM PINTOCANYON RANCH, AND SAN ESTEBAN ROCKSHELTER, SOUTHWESTERN TEXAS

Thu, 12 May 2022 00:00:00 +0000

The mix of sources is similar to the previous study (Shackley 2019a) with none of the sourcesto the west of the Sierra Madre ridgeline in Sonora (see Table 1 and Figure 1; Kibler et al. 2014; Shackley 2005). The TX UnknownA type is also present as well as Mount Taylorobsidian(Grants Ridge) the latter most likely procured from Rio Grande Quaternary alluvium, and two Chihuahuan sources(Lago Fredrico and Lago Barreal) the latter present in the previous study(Church 2000; Shackley 2012).See previous study for a more extensive discussion of sources and regional geology (Shackley 2019b).

SOURCE PROVENANCE OF ARCHAEOLOGICAL OBSIDIAN FROM AZ U:15:24/27 (ASM), NEAR FLORENCE, ARIZONA

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 111 artifacts, 108 obsidian, indicates a somewhat diverse assemblage dominated by artifacts produced from the Superior (Picketpost Mountain; 97.2%) source, the obsidian source nearest the site. Sauceda Mountains obsidian (n=2), and Vulture (n=1), both in west-central Arizona were also present (see discussion).

SOURCE PROVENANCE OF OBSIDIAN PALEOARCHAIC BIFACES FROM THE GREAT BASIN

Thu, 12 May 2022 00:00:00 +0000

The analysis here of 51 Paleoarchaic bifaces (49 obsidian) from the North American Great Basin indicates a very diverse provenance assemblage derived throughout western North America. The XRF analysis and most of the source assignments was performed at the Geoarchaeological XRF Laboratory in Albuquerque, New Mexico, and some of the source assignments, mainly from Oregon sources, was performed by Craig Skinner, former Director of the Northwest Research Obsidian Studies Laboratory, Bend, Oregon. The Skinner/Shackley database of 261 North American obsidian source data was mainly used to assign to source.

MAJOR OXIDE, MINOR OXIDE, AND TRACE ELEMENT ANALYSIS OF CHERT AND QUARTZITE SOURCE MATERIAL FROM THE HARTVILLE UPLIFT, SOUTHEASTERN WYOMING

Thu, 12 May 2022 00:00:00 +0000

The analysis here of chert and quartzite source samples from the Hartville Uplift, Wyoming indicates relatively low variability in the chert samples, and somewhat higher variability in the quartzite samples, particularly in the major and minor oxides and some of the trace elements such as strontium and barium. Also, a previously unpublished analysis by this lab of Spanish Diggings, Wyoming chert for Bruce Huckell at the University of New Mexico is compared to the Hartville chert using the oxides of potassium and calcium, and trace elements Zn and Zr (see also Shackley 1999). This study is mainly seen as an exploratory exercise compositionally documenting the Hartville Uplift chert and quartzite. The comparison with the Spanish Diggings samples is for illustrative purposes.

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF AN OBSIDIAN CORE FRAGMENT FROM LA44517 SOUTHERN NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

The source provenance of the "lonely" bipolar core fragment is Cerro Toledo Rhyolite, and between the waterwom coftex and typical procurement in that par1 of New Mexico was likely procured lrom Rio Grande Quaternary alluvium where Cerro Toledo Rhyolite obsidian is the most commonlyrecovered secondarily deposited obsidian in the Rio Grande gravels at least as far as Las Cruces (Church 2000; Shackley 2005, 2020

AN ENERGY-DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF OBSIDIAN ARTIFACTS FROM LA 104416, SOUTHEAST NEW MEXICO

Thu, 12 May 2022 00:00:00 +0000

All the artifacts were produced from the Cerro Toledo Rhyolite source from the Jemez Mountains, northern New Mexico, although the obsidian is available as secondary deposits in Rio Grande Quaternary alluvium (Church 2000; Shackley 2012; Table 1 and Figure 1 here).

ENERGY-DISPERSIVE X-RAY FLUORESCENCE (EDXRF) ANALYSIS OF MAJOR, MINOR OXIDE AND TRACE ELEMENT CONCENTRATIONS FOR OBSIDIAN ARTIFACTS FROM THE MIDDLE AWASH RIVER BASIN, CENTRAL ETHIOPIA