Instrumental Neutron Activation Analysis Data Research Articles

An Evaluation of Three Halogens (Cl, Br, and I) Data from a Geological Survey of Japan Geochemical Reference Materials by Radiochemical Neutron Activation Analysis

Fifteen Geological Survey of Japan (GSJ) geochemical reference materials were analyzed to determine the contents of three halogens (Cl, Br, and I) by using instrumental neutron activation analysis (INAA) and/or radiochemical NAA (RNAA). Two reference materials (JCp-1 and JSO-1) were analyzed using both INAA and RNAA. Although there were discrepancies in Cl and Br for JCp-1 between the INAA and RNAA data, probably due to sample heterogeneity, the INAA and RNAA data for JSO-1 were consistent with each other, within less than 7%, indicating that our RNAA data are reliable. With the repeated analyses of JR-3, the external repeatability of the data obtained using RNAA was evaluated to be 18% for Cl, 11% for Br, and 19% for I. Our RNAA data are in agreement with literature values using NAA for the three halogens, as well as those using isotope dilution mass spectrometry and ion chromatography for Cl. Systematically lower values when using neutron irradiation noble gas mass spectrometry (NI-NGMS) and inductively coupled plasma mass spectrometry (ICP-MS) with pyrohydrolysis can be observed, implying that there are losses for noble gas nuclides produced through the beta-decay of the neutron capture halogen nuclides in NI-NGMS and the non-quantitative recovery of Br and I during procedures in ICP-MS, respectively.

Compositional analysis of Apollo 12 Granitic Breccia 12013: Insights into protoliths and formation

We report bulk rock composition and mineral chemistry of previously unstudied fragments and thin sections of lunar granitic breccia 12013. Instrumental Neutron Activation Analysis data on 25 fragments indicate that the 12013 breccia can be described as a three-component system comprising granitic, rare earth element (REE)-rich, and mafic components. The granitic component is low in FeO and REE but rich in K2O, Th, and associated incompatible elements. The REE-rich component has an elevated concentration of REE, moderate FeO, and low concentrations of those elements that are high in the granitic component, in other words, its composition is complementary to that of the granitic component. The mafic component is richest in FeO, and low in those elements that are concentrated in the granitic and REE-rich components. Petrographically, the REE-rich component is an impact melt breccia with a composition unique to Apollo 12 impact melt breccias. Trace-element concentrations in the REE-rich component indicate that its protolith is possibly monzogabbro, although its composition is significantly more magnesian than other known lunar monzogabbros. The mafic component is dominated by fine-grained pyroxene and plagioclase that appear to have recrystallized after impact. However, preserved lithic clasts with an igneous texture occur in the mafic component and are inferred to represent its protolith. The textures of the preserved mafic lithic fragments and lack of Mg-Fe zoning in pyroxene indicate that the protolith of the mafic component formed either as a crustal intrusion or at the bottom of a thick lava flow. The composition of the mafic component is unlike any previously studied mare basalt samples. Textures of this complex breccia suggest that the granitic breccia was first incorporated with the mafic component to form the “gray breccia”, and that the gray breccia was then incorporated with the REE-rich component while the components were still in a hot, plastic state. The complementary trace-element compositions, including the REE patterns, indicate that the petrogenesis of the granitic and REE-rich components are related. We infer that silicate-liquid immiscibility is likely not the formation mechanism for the 12013 components. Instead, bimodal volcanism owing to basaltic underplating may have led to the formation of the 12013 components.

Provenancing of pottery from Kamuiyaki Site in East Asia by neutron activation analysis

A set of 20 vessels was selected from the Japanese National Historical Site ‘Kamuiyaki Kiln Site Cluster’. Selection was performed with explicit archaeological problems and the potential of instrumental neutron activation analysis (INAA) in mind. The set was analysed by INAA and subsequent statistical data analysis adapted to the specific problems of ceramics and applied for the first time in Kamuiyaki. Chemical fingerprinting allowed the a priori separation of the set of samples into two chemically distinct groups that had a clear correlation with the archaeological and chronological data. This indicates that at least two different recipes or sediments were used in the cluster, which can now be identified among the several hundred external sites where sherds are recorded as supposedly produced at Kamuiyaki.

A comparison of INAA and ICP-MS/ICP-AES methods for the analysis of meteorite samples

Instrumental neutron activation analysis (INAA), inductively coupled plasma atomic emission spectrometry (ICP-AES) and ICP mass spectrometry (ICP-MS) (hereafter, ICPs) were applied to meteorite samples for the determination of elemental content. The analytical applicability and suitability of the three methods have been compared. Those comparisons led to the refinement of our analytical procedures for INAA and ICPs, yielding more reliable data. Our INAA data proved to be reliable enough for classifying meteorites, while the ICPs, especially ICP-MS, can characterize elemental abundance features in detail, as demonstrated by REE abundance patterns for the Allende meteorite. In this manner, INAA and ICPs can be used in a complementary fashion in cosmochemical studies.

Rare earth elements in select Main Karoo Basin (South Africa) coal and coal ash samples

Internationally, the demand for a variety of rare earth elements (REY/REY + Sc) (i.e. Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) for use in modern electronic and related components is increasing. This demand has led to a need to expand extraction from alternative sources, such as coal and combustion ash. South Africa has extensive coal resources and generates a significant amount of coal ash. The aim of the study is to determine the levels of REY + Sc in three South African power station feed coals and their associated ash products (eight samples), with a consideration of the viability of commercial extraction of REY + Sc from these materials. The coal and ash samples were analysed using a variety of routine and advanced techniques, including petrography, Malvern particle size analysis, X-ray diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS), and instrumental neutron activation analysis (INAA). Total REY concentrations ranged from 95 to 149 ppm in the coal samples, and H– and M-type REY enrichment types were determined. Total REY concentrations ranged from 402 to 599 ppm in the ash samples, far higher than the average upper crustal values, and higher than global average hard coal ash values, but lower than REY-rich coal ashes recorded for various deposits globally. The INAA data are comparable to the ICP-MS data for most elements considered, and Sc was determined. Further investigations are required to confirm the potential of the Main Karoo Basin coal ash for economically viable REY extraction.

Neural Networks (SOM) Applied to INAA Data of Chemical Elements in Archaeological Ceramics from Central Amazon

ABSTRACTArtificial neural networks represent an alternative to traditional multivariate techniques, such as principal component and discriminant analysis, which rely on hypotheses regarding the normal distribution of the data and homoscedasticity. They also may be a powerful tool for multivariate modeling of systems that do not present linear correlation between variables, as well as to visualize high-dimensional data in bi- or trivariate structures. One special kind of neural network of interest in archaeometric studies is the Self-Organizing Map (SOM). SOMs can be distinguished from other neural networks for preserving the topological features of the original multivariate space. In this study, the self-organizing maps were applied to concentration data of chemical elements measured in archaeological ceramics from Central Amazon using instrumental neutron activation analysis (INAA). The main objective was testing the chemical patterns previously identified using cluster and principal component analysis, forming groups of ceramics according the multivariate chemical composition. It was verified by statistical tests that the chemical elemental data was not normally distributed and did not present homogeneity of covariance matrices for different groups, as requested by principal component analysis and other multivariate techniques. The maps obtained were consistent with the patterns identified by cluster and principal component analysis, forming two chemical groups of pottery shards for each archaeological site tested. Finally, it was verified the potential of SOMs for testing if failures in underlying hypotheses of traditional multivariate techniques might be critically influencing the results and subsequent archaeological interpretation of archaeometric data.

Spanish olive jars in Campeche: Preliminary chemical characterization and provenance identification of early modern transport vessels in the Yucatán Peninsula (Mexico)

Olive jars, also known asbotijas, were used during the early modern period to ship products between Spain and its colonies. Studies of their provenance allow direct insight into the commercial networks that were in operation in any given region. Instrumental neutron activation analysis (INAA) was conducted on 49 fragments recovered from recent excavations at the port of Campeche in the Yucatán Peninsula, Mexico. The results show that a great majority of the samples have a shared origin. Comparison of the resulting geochemical data with other INAA data sets of bothbotijasand majolica made it possible to assign provenance to this main group of Campeche specimens: the Sevillian suburb of Triana. We have not yet found evidence in Campeche to support that smuggling, alternate and more popular trade routes from the Canary Islands, or the start of free, direct trade with several peninsular Spanish ports initiated by the Bourbon reforms demanded the production of these containers in places other than Seville. Evidence for the latter may be found in Late Style specimens, which may have escaped our sampling.

Chemical and mineralogical compositions of two grains recovered from asteroid Itokawa

AbstractTwo silicate grains (RB‐QD04‐0049 and RA‐QD02‐0064, whose estimated masses are 0.050 μg and 0.048 μg, respectively) recovered from the asteroid Itokawa by the Hayabusa spacecraft were studied for their mineralogical characteristics by synchrotron X‐ray diffraction and synchrotron X‐ray microtomography and further analyzed for their bulk chemical compositions by instrumental neutron activation analysis (INAA). According to X‐ray tomography, RB‐QD004‐0049 is composed of olivine, high‐Ca pyroxene, plagioclase, Ca‐phosphate, and troilite, whereas RA‐QD002‐0064 entirely consists of olivine. INAA data are consistent with these mineral compositions except for rare earth elements (REEs). Although the grain RB‐QD004‐0049 contains measurable REEs, which seems to be consistent with the presence of Ca‐phosphate, their abundances are anomalously high. Very low abundance of Co implies less than 0.1 mass% of metals in these two grains by calculation, which is in contrast to the result for the previously analyzed grain RA‐QD02‐0049 (Ebihara et al., 2011). FeO/Sc ratios of the grains fall within the range of those for ordinary chondrite olivines, implying that these grains are extraterrestrial in origin. FeO/MnO ratios also confirm this conclusion and further suggest that the Hayabusa grains analyzed in this study are similar to material found in LL chondrites rather than CK chondrites although olivines from LL and CK chondrites have similar Fa# (molar% of Fe relative to [Fe+Mg] in olivine) (~30) to those of the Hayabusa grains including the two grains analyzed in this study.

Siderophile elements in chondrules of CV chondrites

New bulk compositional data for 34 Allende chondrules are presented. Whole chondrules were analyzed by instrumental neutron activation analysis (INAA). The new data set is evaluated together with older INAA data on Allende chondrules and recent INAA data on Mokoia chondrules. The Ni/Co ratios of 200 chondrules are close to the CI- or solar ratio. The chondritic Ni/Co ratios require an unfractionated chondritic metal source and set a limit to the fraction of metal lost from molten chondrules. The bulk chondrule Fe/Ni and Fe/Co ratios are more variable but on average chondritic. Iridium and other refractory metals have extremely variable concentrations in chondrules. High Ir chondrules have chondritic Ir/Sc ratios. They are dominated by CAI (Ca,Al-rich inclusion) components. Low Ir chondrules have approximately chondritic Ir/Ni ratios reflecting mixing with chondritic metal. In low Ir chondrules Ir correlates and in high Ir chondrules Ir does not correlate with Ni or Co. A large fraction of Ir may have entered chondrules in variable amounts as tiny grains of refractory metal alloys.Most Allende chondrules have Ir/Sc ratios below bulk meteorite ratios. Matrix must have a complementary high Ir/Sc ratio, as bulk Allende has approximately chondritic Ir/Sc ratio. Similarly, the high average Ir/Ni ratios of Allende chondrules must be balanced by low Ir/Ni ratios in matrix to obtain the bulk Allende Ir/Ni ratio, which is close to the average solar system ratio.More recent data on single chondrules from Allende by ICP-MS (Inductively Coupled Plasma Mass Spectrometry) and ICP-OES (Inductively Coupled Optical Emission Spectrometry) show the same trends as the INAA data discussed here.

INAA and the provenance of shell-tempered sherds in the ancestral Caddo region

Over the last two decades, archaeologists working in the ancestral Caddo area have amassed a sizeable instrumental neutron activation analysis (INAA) dataset (n = 1308 sherds). We examine a subset (n = 88 sherds) of that larger dataset—shell-tempered Caddo ceramics—to examine the issue of ceramic provenance determinations from INAA in the Caddo area. Current analyses of INAA data from Caddo area shell-tempered ceramics mistakenly suggest that very distinctive shell-tempered ceramics were manufactured throughout East Texas and not traded and/or exchanged from one sub-region to another. Through the protocol of removing calcium-related geochemicals from statistical calculations of elemental values, shell-tempered sherds have lost their distinctive chemical signature. The methodological approach employed herein illustrates the potential for significant gains in exploring the provenance of Caddo ceramics using INAA, through the use of geochemicals found to correlate with the inclusion of shell temper.

Quality assessment of INAA data for small-sized environmental reference samples.

Instrumental neutron activation analysis (INAA) was applied for the accurate and precise determination of minor and trace elements in small-sized aliquants (1 to 2 mg) of two certified reference materials (CRM), NIES No. 8 and NIST 1632c. Four laboratories used either comparative- or k0-INAA, or both, and repeated the analysis more than ten times for each CRM. Based on z-scores and zeta scores of analytical data, QA/QC in analyzing such small scale of the two reference samples was assessed, revealing that there was a clear difference in the analytical ability among participating laboratories. It was concluded that the two CRM samples on the mg scale can be used as reference samples in INAA of a similarly small-scaled sample, at least for the 16-18 elements examined.

Determination of reference interval values for inorganic elements in whole blood samples of humans and laboratory animals by X-ray fluorescence spectrometry

Inorganic elements are responsible for essential bodily functions, such as osmotic regulation, cardiac frequency and contractibility, blood clotting and neuromuscular excitability. The determination of inorganic elements in corporeal fluids such as blood, serum, plasma and urine is used as a monitor for a part or the whole organism; their values, then, are compared with reference interval values. In this study, the energy dispersive X-ray fluorescence spectrometry (EDXRF), applying the Fundamental Parameters method, for the determination of inorganic elements in whole blood samples from humans and laboratory animals, was used. Peripheral blood samples were collected and, before coagulation, 100 μL of sample were deposited onto Whatman No. 41 filter paper and dried, using infrared spotlight. The reference interval values for healthy Brazilian population of Na were found to be 1,788–1,826 μg g−1, of Mg 63–75 μg g−1, of P 602–676 μg g−1, of S 1,519–1,718 μg g−1, of Cl 2,743–2,867 μg g−1, of K 1,508–1,630 μg g−1, of Ca 214–228 μg g−1, of Fe 170–184 μg g−1, of Cu 4–6 μg g−1 and of Zn 1–3 μg g−1. The reference interval values for golden hamster (Mesocricetus auratus) of Na were found to be 1,714–1,819 μg g−1, Mg 51–79 μg g−1, P 970–1,080 μg g−1, S 1,231–1,739 μg g−1, Cl 2,775–2,865 μg g−1, of K 1,968–2,248 μg g−1, of Ca 209–257 μg g−1, of Fe 145–267 μg g−1, of Cu 4–6 μg g−1 and of Zn 3–5 μg g−1. A comparative study between EDXRF and instrumental neutron activation analysis data was carried out and the results for both techniques are statistically equal (α = 0.05). The results contribute for the establishment of reference interval values for Na, Mg, P, S, Cl, K, Ca, Cu and Zn in the healthy Brazilian population and the referred laboratory animal species.

Compositional and petrographic similarities of CV and CK chondrites: A single group with variations in textures and volatile concentrations attributable to impact heating, crushing and oxidation

Greenwood et al. (2010) gathered data on O-isotopic and elemental compositions and reevaluated literature data for CV and CK chondrites. They concluded that these two chondrite groups originated on the same parent asteroid, with CK chondrites being metamorphosed CV chondrites (which are otherwise missing types 4 through 6). To test this interpretation we have gathered new instrumental neutron-activation-analysis (INAA) data for CV and CK chondrites and reexamined their petrographic features. The new INAA data like the older data show scatter attributable to weathering effects, but we conclude that the refractory lithophile abundances are the same in CV and CK, in agreement with the Greenwood et al. interpretation. Several volatile elements are significantly lower in CK than in CV chondrites. Among the elements we determine, the greatest difference between CV and CK is found for Br, for which the CV/CK ratio is ∼4; As and Sb are about 20% lower in CK than CV and smaller differences are observed for Zn, Ga and Se. It seems likely that volatiles were lost during impact-heating events that also provided the heat responsible for metamorphic recrystallization. Within statistical uncertainty, chondrules in CV and CK chondrites are the same size and have similar textural distributions. A significant petrographic difference between CK and CV chondrites cited by Kallemeyn et al. (1991) was the much higher percentage of igneous rims around CV chondrules. However, we now recognize that many chondrules in CK3.8 NWA 1559 have igneous rims and in CK4 chondrites, igneous rims are recognizable by their associated sulfide-rich rings; there are no quantifiable CV–CK differences in igneous-rim abundances. We used Ca and Al maps to show that CK chondrites have CAI abundances similar to those of CV chondrites. It thus appears that there are no resolvable pre-metamorphic petrographic differences between CV and CK chondrites. We recommend that the “CK” designation be abandoned and that the CV group be acknowledged as spanning the range of petrologic types 3–6. We suggest that CK3 chondrites be designated CV3OxK. Most CK4 chondrites are highly fragmental; collisional crushing appears to be much more common than in CV chondrites. It seems likely that CK chondrites formed from reduced CV3 materials after the latter was impacted, buried, aqueously altered and annealed.

Characterization of ancient glass excavated in Enez (Ancient Ainos) Turkey by combined Instrumental Neutron Activation Analysis and Fourier Transform Infrared spectrometry techniques

Ancient glass fragments excavated in the archaeological district Enez (Ancient Ainos)–Turkey were investigated by combined Instrumental Neutron Activation Analysis (INAA) and Fourier Transform Infrared (FTIR) spectrometry techniques. Multi-elemental contents of 15 glass fragments that belong to Hellenistic, Roman, Byzantine, and Ottoman Periods, were determined by INAA. The concentrations of twenty six elements (Na, K, Ca, Sc, Cr, Mn, Fe, Co, Cu, Zn, As, Rb, Sr, Sb, Cs, Ba, Ce, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au and Th), which might be present in the samples as flux, stabilizers, colorants or opacifiers, and impurities, were examined. Chemometric treatment of the INAA data was performed and principle component analysis revealed presence of 3 distinct groups. The thermal history of the glass samples was determined by FTIR spectrometry.

Analytical Methods INAA and PIXE Applied to Characterization of Airborne Particulate Matter in Bandung, Indonesia

Urbanization and industrial growth have deteriorated air quality and are major cause to air pollution. Air pollution through fine and ultra-fine particles is a serious threat to human health. The source of air pollution must be known quantitatively by elemental characterization, in order to design the appropriate air quality management. The suitable methods for analysis the airborne particulate matter such as nuclear analytical techniques are hardly needed to solve the air pollution problem. The objectives of this study are to apply the nuclear analytical techniques to airborne particulate samples collected in Bandung, to assess the accuracy and to ensure the reliable of analytical results through the comparison of instrumental neutron activation analysis (INAA) and particles induced X-ray emission (PIXE). Particle samples in the PM 2.5 and PM 2.5-10 ranges have been collected in Bandung twice a week for 24 hours using a Gent stacked filter unit. The result showed that generally there was a systematic difference between INAA and PIXE results, which the values obtained by PIXE were lower than values determined by INAA. INAA is generally more sensitive and reliable than PIXE for Na, Al, Cl, V, Mn, Fe, Br and I, therefore INAA data are preffered, while PIXE usually gives better precision than INAA for Mg, K, Ca, Ti and Zn. Nevertheless, both techniques provide reliable results and complement to each other. INAA is still a prospective method, while PIXE with the special capabilities is a promising tool that could contribute and complement the lack of NAA in determination of lead, sulphur and silicon. The combination of INAA and PIXE can advantageously be used in air pollution studies to extend the number of important elements measured as key elements in source apportionment. Received: 20 November 2010; Revised: 09 August 2011; Accepted: 15 August 2011

Use of neutron activation analysis for the characterization of single-wall carbon nanotube materials

Instrumental neutron activation analysis (INAA) and prompt gamma neutron activation analysis (PGAA) were used to characterize a variety of single-wall carbon nanotube (SWCNT) materials from different principal production processes, as well as a material containing SWCNTs together with other carbon species, catalyst residues, and trace element contaminants to be issued by the National Institute of Standards and Technology for characterization and distribution as Standard Reference Material SRM 2483 Carbon Nanotube Soot. INAA proved to be well suited for the direct determination of catalyst and contaminant trace elements requiring only minimal sample preparation. PGAA complemented the INAA data in particular with determinations of the light elements. Carbon and hydrogen results provided information on the materials purity and storage properties. Strategies for the quality assurance of the measurements in these new materials were developed. INAA and PGAA data were provided for the value assignment of mass fractions of catalyst and trace elements in the candidate SRM and a systematic overview was obtained of the catalyst and trace element contaminants associated with each of the major production routes.

Changes in regional organization and mobility in the Zuni region of the American Southwest during the Pueblo III and IV periods: insights from INAA studies

The transition from the late Pueblo III (AD 1200–1275) to Pueblo IV (AD 1275–1400) period marks one of the most dramatic eras of demographic and social upheaval in the American Southwest. At this time, much of the northern Southwest was depopulated as thousands of ancestral Pueblo people moved to new homelands. In the Zuni region, this transition included a residential shift from dispersed, largely household-scale settlements to massive, multi-storied pueblos housing hundreds of people and a simultaneous contraction of regional settlement to a central core along the Zuni River and its major tributaries. This article presents a synthesis of our recent independent efforts to utilize instrumental neutron activation analysis (INAA) to investigate changes in social interaction in the Zuni region before and after this transition. We suggest that in addition to significant local and regional settlement shifts, the Pueblo III–IV transition in the Zuni region was accompanied by a major reorganization of pottery distribution networks as clear social boundaries began to emerge between village clusters. More generally, our combined study also highlights the iterative nature of INAA data analysis, the benefits of large sample sizes, and the utility of a diachronic interpretative approach.

Chemical tracers of Lusitanian amphorae kilns from the Tagus estuary (Portugal)

In this paper, the characterization of Roman amphorae from the Porto dos Cacos (PC) and Quinta do Rouxinol (QR) workshops, in the Tagus estuary, dating to a period between the 1st and 5th century AD was carried out on the basis of instrumental neutron activation analysis data on 260 amphorae fragments, together with mineralogical compositional studies obtained by X-ray diffraction. Special attention was devoted to the study of the Dressel 14, Almagro 50/51c and Lusitana 3/9 amphorae in an attempt to establish whether or not it is possible to establish any correlation between the composition and typology, and between and within the production centres studied. A description of the geochemical patterns associated with each production centre was first carried out separately, followed by a discussion comparing the two centres situated in the same sedimentary basin, identifying diagnostic chemical tracers for each one; also, in certain cases, a relative correlation with the typology was achieved. Both the definition of reference groups and the attribution of amphorae to their workshop origin relied on the use of chemometric techniques for data structure analysis, coupled with geochemical data analysis, especially regarding trace element data and its geochemical behaviour and distribution according to the geological environment of the region. This approach complements and reinforces the conclusions drawn from typological and archaeological analyses. Considering the two kiln sites studied, we may talk of the production of two types of Roman amphorae in the lower Tagus, with the establishment of compositional groups defined according to their corresponding chemical signatures. The products of the PC workshop are characterized by high concentrations of Co, As and U, and low concentrations of Fe, Zn, Sb, Rb, K; QR workshop amphorae show instead higher concentrations of Fe, Sb, and also of Rb and Zn, and lower amounts of U. These results make it possible to understand the crucial importance of the lower course of the Tagus River within the framework of the analysis of the economy of the estuary at the time. This, in turn, may lead to a better understanding of production and trade within Lusitania and also with other Roman provinces.

The GRO 95577 CR1 chondrite and hydration of the CR parent body

Abstract— We carried out a petrologic and instrumental neutron activation analysis (INAA) whole chondrite compositional study of Grosvenor Mountains (GRO) 95577. GRO 95577 has many petrological similarities to the CR chondrites. Although the INAA data show patterns indicative of terrestrial weathering, some of the elemental abundances are consistent with a relationship to CR chondrites. The oxygen isotopic composition of GRO 95577 plots close to the Renazzo CR chondrite on the three‐isotope diagram. However, GRO 95577 is remarkable in that the chondrules are completely hydrated, consisting almost entirely of phyllosilicates, magnetite, and sulfides. Although GRO 95577 is completely hydrated, the initial chondrule textures are perfectly preserved. The chondrules are in sharp contact with the matrix, their fine‐grained rims are clearly visible, and the boundaries of the dark inclusions can be easily discerned. Many chondrules in GRO 95577 have textures suggestive of type I chondrules, but the phenocrysts have undergone perfect pseudomorphic replacement by yellow to brownish serpentine‐rich phyllosilicate, with sharp original crystal outlines preserved. The chondrule mesostasis is a green aluminous chlorite‐rich material, most likely a hydration product of the feldspathic mesostasis commonly found in anhydrous type I chondrules. Some chondrules contain magnetite spheres, most likely formed by oxidation of metal. We propose that GRO 95577 be classified as a CR1 chondrite, making it the first known CR1 chondrite and expanding the range of alteration conditions on the CR parent body.

INAA of pre-contact basalt quarries on the Samoan Island of Tutuila: a preliminary baseline for an artifact-centered provenance study

This project presents a material-centered instrumental neutron activation analysis (INAA) characterization of 120 geologic samples selected from four fine-grained basalt quarries on the Samoan Island of Tutuila. Previous attempts at definitive differentiation of these Tutuilan quarries have utilized x-ray fluorescence (XRF). In this study, clear differentiation of each analyzed quarry was achieved using INAA. Biplots of canonical discriminant analysis (CDA) scores for the INAA data illustrate clear separation based on the variation in chemical composition between each quarry. The samples analyzed not only define quarry separation, but also provide the “core group” for a preliminary baseline necessary for future artifact-centered provenance studies. Inclusion of these “core group” samples in the baseline was confirmed by stepwise discriminant analysis. These findings suggest the ability to determine artifact quarry of origin on the island of Tutuila, which can elucidate the importance of individual Tutuilan quarries in the production, distribution and consumption of fine-grained basalt artifacts in Polynesia.