Wayne Powell

The lack of historically known tin deposits in Poland requires that the source of tin metal in ancient artifacts must be derived from foreign sources. To identify these external sources in the Viking Period, a combination of Pb and Sn isotope compositions and trace element analyses on a group of tin and tin rich alloys from three settlements in Poland was conducted. The integration of the chemical techniques reveals several sources for the tin rich artifacts, where group: 1) possesses Pb isotope values that overlap the Europe array which possess the highest (+1.6 ‰) and lowest (− 1.1 ‰) Sn isotope values coupled with elevated In concentrations 2) has Pb isotope values that overlap the Slovakian array which possess lower Sn isotope values (+0.1 ‰ to + 0.3 ‰) coupled with low In and Te concentrations 3) has a Pb isotope value that is radiogenic which possesses a high Sn isotope value (+1.1 ‰). Group 1 artifacts are split into two sources designated by the higher Sn isotope values from Cornwall and the lower Sn isotope values from Brittany and are found in the two coastal settlements. Group two artifacts match a Slovakian origin, while one artifact labeled in group three possesses an Anatolian source. Defining the tin rich artifact sources allows constraint of the tin sources for the mixed alloys like bronze and pewter. In this instance the tin isotope values fall within two sources defined by the tin metal artifacts, Brittany and Cornwall. The chemical approach presented here defines distal metal sources to reveal a geographically expansive interconnected tin trade network that was predominantly European, in Viking times through chemical analysis of ornaments, coins, and beads.

Spasovine, on the south flank of Mt. Cer in West Serbia, is one of the rare localities where Late Bronze Age placer tin mining activities have been documented. Archeological pedestrian surveys on this river terrace recovered ceramic fragments with metal-rich coatings, thought to be fragments of technical ceramics. The physical characteristics of the “petrol” gray-bodied ceramics are consistent with Roman Period ca. 200-300AD production, while black-bodied sherds are most consistent with Iron Age ceramics of western Serbia. SEM-EDS analysis of polished thin-sections and rough surfaces has shown that the fragments are enriched in various metallic residues (Zn, Sn, Cu, Pb in various combinations). Of the fourteen sherds studied, nine Roman samples contain Zn-rich coatings on the inner surfaces as well as deeper penetration of zinc enrichment into the ceramic interior, consistent with Zn cementation for brass. Three of these also contained younger addition of Sn, indicating that they were repurposed for bronze production at Spasovine. The prehistoric sherds contain tin along with Cu and Pb, consistent with the production of leaded tin bronze, which is not known from the area until the Iron Age (ca. 800-600BC). Thus, Spasovine was the site of itinerant mining and metallurgical activity, at least sporadically, over a period of 1700 years from the Late Bronze Age (14th century BCE) to the Roman Period (2nd-3rd century CE). This demonstrates that small deposits of placer tin could have had long-term impact on regional tin economies in ancient Europe.

Study of noncalcareous algal fossils is problematic due to their broadly defined taxonomy and lack of preserved features by which modern algae are classified. Four distinct morphologically simple, enigmatic fossils from the Wheeler Formation were analyzed using Raman spectroscopy, and elemental mapping by electron microbeam techniques. These fossils have been interpreted as dissociated algal fragments, and accordingly, were compared to known algal fossils: Yuknessia simplex (green alga; Spence Shale), Marpolia spissa (cyanobacteria; Burgess Shale), and Margaretia dorus (green alga; Burgess and Wheeler formations). All fossils examined were composed of carbonaceous films, at least in part, but varied with respect to secondary mineral coatings: iron oxides were associated with the surfaces of all three algal species to some degree, and in addition, Margaretia dorus exhibited silicification. Fossils characterized by a thin, wispy, filamentous form (Linear Morphotype 2) display mineralo...

Lead isotope analysis (LIA) can be applied to tin provenance studies when both the U–Th–Pb characteristics of cassiterite and potential Pb contamination are taken into account. As cassiterite (SnO2) contains higher con-centrations of U than Pb and negligible Th, radioactive decay increases 206Pb/204Pb and 207Pb/204Pb ratios in cassiterite over time. However, 208Pb/204Pb ratio retains its primary value and can be correlated with LIA da-tabases. A majority of documented Bronze Age tin ingots from Europe have Pb in excess of the 5 ppm maximum that can be derived from Cenozoic to Late Paleozoic cassiterite. A minute mass of galena (PbS) in the ore concentrate is sufficient to mask the cassiterite-derived lead, as would the addition of any lead contaminant introduced in the smelting/casting process. If the galena is cogenetic with the cassiterite, then LIA will be un-affected. The inclusion of uranium-rich minerals in the tin ore concentrate is another potential source of excess lead. In this case, the additional Pb is uranogenic, and so 206Pb/204Pb and 207Pb/204Pb will reflect the age of the uranium minerals, but 208Pb/204Pb will retain its primary value. If the U-minerals are cogenetic or coeval with tin mineralization, then a Pb isochron age will indicate the age of the ore. Between 1984 and 1994, at least 117 ingots, or roughly one tonne, of tin was raised from the Late Bronze Age Uluburun shipwreck (ca. 1320 B.C.). Over half of the analyzed ingots from this wreck site have high Pb con-centrations (>100 ppm), indicative of contamination from non-radiogenic lead associated with lead metal or galena. LIA indicates that the Pb originated from the Pb–Ag-rich Bolkarda ̆g region of the south-central Taurus Mountains. A second group of approximately 28 tin ingots with lower Pb content (<100 ppm) contain additional uranogenic Pb but retain 208Pb/204Pb compositions that overlap with the ca. 300 Ma tin regions of Western Europe and Central Asia, with the most likely source being the Tienshan Mountains in Kyrgyzstan, Tajikistan, and Uzbekistan. By compensating for previous uncertainty around the use of Pb isotopes for sourcing tin objects, it is now possible to contextualize the Uluburun tin ingots more securely within the metallurgical systems of the Central Taurus-Cilicia-Amanus axis. Recent scholarship has shown that tin production in the South-Central Taurus region had taken place at a scale not previously anticipated. Two parallel production systems appear to have been in place serving elite and common consumption networks via markedly different technologies. The South-Central

Since its discovery in 1987, the Early Bronze Kestel Mine has been a topic of archaeological and geological controversy. The initial interpretation of the extensive marble-hosted galleries as the oldest known tin mine was challenged due to the low tin grade in remaining hematite-quartz veins, and it was suggested that Kestel was more likely mined for gold. Mineralogical analysis of the remaining mineralization was compared to a heavy mineral concentrate extracted from the soil
preserved within the mine. The compositionally complex, arsenate-rich mineral assemblage from the mine sediment, contrasts with that of the remaining surface mineralization. Thus, the outcropping veins do not represent the nature of the extracted ore. Only one grain of gold was found in the heavy mineral concentrate, whereas cassiterite composed 1.5% of the sample. Cassiterite occurs in complex assemblages with arsenates, clays, hematite, quartz, and dolomite, bearing resemblance to
hematite-arsenate tin mineralization that occurs near Kayseri, 60 km to the northeast. These findings indicate that although gold was a trace component of the Kestel ore, cassiterite was the mineral of interest to the Early Bronze Age miners, and that Kestel represents the earliest evidence thus far for an emerging pattern of local tin exploitation.

Archaeological finds at Spasovine, on the south flank of Mt Cer, near the town of Milina, indicate that it was settled in the Eneolithic and seasonally inhabited for tin placer mining in the Late Bronze Age. The site is highly disturbed and abraded domestic pottery is the most common material found. An analysis of the mineralogical assemblages that comprise the temper sand in a subset of the prehistoric pottery sherds from the site indicate that the sand was obtained from the adjacent Milinska River. Key minerals that link the pottery to on-site production from local materials include almandine-spessartine series garnets, the tin-bearing mineral cassiterite (SnO2) and a microlite group mineral ([Ca,Sn,U]2[Ta,Nb]2O6(OH,F]). The unusually common occurrence of cassiterite within the pottery sherds relative to the abundance in the Milinska today suggests that the tin ore grade in the Milinska River may have been significantly higher in prehistory.

Abstract. – The important role of the Balkans in the origin and development of metallurgy is well established with respect to copper. In addition, Aleksandar Durman, in his 1997 paper “Tin in South-eastern Europe?”, essentially initiated studies into the
role of the Balkans in Europe’s Bronze Age tin economy. He identified six geologically favourable sites for tin mineralisation and associated fluvial placer deposits in the former Yugoslavian republics, and suggested that these may have added to the tin supply of the region. The viability of two of these sites has been confirmed (Mt Cer and Bukulja, Serbia) but the exploitation potential for the other locations has remained untested. River gravels from these four sites (Motajica and Prosara in Bosnia and Herzegovina; Bujanovac in Serbia; Ogražden in North Macedonia) were obtained by stream sluicing and panning. The sites of Prosara and Bujanovac were found to be barren with respect to cassiterite (SnO2). Streams flowing from Motajica and Ogražden were both found to contain cassiterite, but in amounts several orders of magnitude less than at Mt Cer and Bukulja. Although it is possible that minor tin recovery occurred at Motajica and Ogražden, it is unlikely that they could have contributed meaningfully to regional tin trade. This is supported by the fact that the isotopic signature (δ124Sn) of cassiterite from Motajica is highly enriched in light
isotopes of tin compared to that associated with Late Bronze Age artefacts of the region.

We report the largest published dataset to date of Sn-isotopic compositions of Bronze Age artifacts (338) along with 150 cassiterite samples (75 new) from six potential tin ore sources from which the tin in these artifacts were thought to have likely originated. The artifacts are from a broad area, Central Europe through the Central Balkans, and the six tin sources are Cornwall, three sites in the Erzgebirge, and two sites in Serbia. A clustering analysis on mean site-level isotopic values of δ 124 Sn identifies regional variation that can be attributed to the use of different tin ore sources in different regions. Therefore, geographically meaningful regions were identified to group the Bronze Age artifact assemblages and a probabilistic, Bayesian analysis was performed to determine the proportional contribution of each tin source to each regional assemblage. Artifacts enriched in heavy isotopes (δ 124 Sn > 0.7‰) that cluster in west-central Serbia are likely associated with the ores from Mt. Cer in west Serbia. Mixed artifact assemblages (high and low δ 124 Sn) in this region are attributed to the use of cassiterite from the two Serbian sites (Mt. Cer and Mt. Bukulja). Moderate composition artifacts that occur north of the Middle Danube in Vojvodina, Transylvania, and Central Europe are likely associated primarily with ores from the West Pluton of the Erzgebirge. Compositionally light bronzes (δ 124 Sn < 0.2‰) in southern Serbia and the lower Danube river valley cannot be linked to a documented ore source. There is no indication of the use of ores from Cornwall or the East Pluton of the Erzgebirge in Central Europe and the Balkans during the Late Bronze Age.

We report the largest published dataset to date of Sn-isotopic compositions of Bronze Age artifacts (338) along with 150 cassiterite samples (75 new) from six potential tin ore sources from which the tin in these artifacts were thought to have likely originated. The artifacts are from a broad area, Central Europe through the Central Balkans, and the six tin sources are Cornwall, three sites in the Erzgebirge, and two sites in Serbia. A clustering analysis on mean site-level isotopic values of δ 124 Sn identifies regional variation that can be attributed to the use of different tin ore sources in different regions. Therefore, geographically meaningful regions were identified to group the Bronze Age artifact assemblages and a probabilistic, Bayesian analysis was performed to determine the proportional contribution of each tin source to each regional assemblage. Artifacts enriched in heavy isotopes (δ 124 Sn > 0.7‰) that cluster in west-central Serbia are likely associated with the ores from Mt. Cer in west Serbia. Mixed artifact assemblages (high and low δ 124 Sn) in this region are attributed to the use of cassiterite from the two Serbian sites (Mt. Cer and Mt. Bukulja). Moderate composition artifacts that occur north of the Middle Danube in Vojvodina, Transylvania, and Central Europe are likely associated primarily with ores from the West Pluton of the Erzgebirge. Compositionally light bronzes (δ 124 Sn < 0.2‰) in southern Serbia and the lower Danube river valley cannot be linked to a documented ore source. There is no indication of the use of ores from Cornwall or the East Pluton of the Erzgebirge in Central Europe and the Balkans during the Late Bronze Age.

The hoards from northern Bosnia, especially those along the wider stream area of river Bosna, are culturally and technologically interpreted in close connection with the emanating pattern of their manifestation in the wider area of south-western Pannonia and the extremely rich Posavina region within it. Data on 11 hoards in the region currently exists, with around 570 items and fragments recorded within these. Most hoards are considered to be representative of the cultural circumstances of the time and place in which they were deposited. Among them are included several exceptionally interesting recently published hoards from Majdan/Ridžal, Paležnica and Srebrenik, each with their own idiosyncrasies. These are now complemented by a hoard from Cvrtkovci, which is presented here in greater detail. All of these hoards, through typological-stylistic analysis and chronological attribution, have been attributed to the earlier period of the Urnfield culture, i.e., defined as falling within the range of phase II hoards of Bosnia and Herzegovina. As a result, they are deemed to be characteristic of an integral part of the enigmatic Pan-European phenomenon of the Late Bronze Age, synchronized with the Ha A1 phase of Central European periodization of the 13th and 12th centuries BC.
In the analyses of Bosnian hoards undertaken to date, an emphasis has been placed on the interpretation of objects as a valuable resource for typological and chronological evaluation, an approach that also forms the basis of this research. However, questions as to the spatial arrangement of the hoards within the landscape, interpersonal connections and origins have only recently been raised, and here, for the first time, an archaeo-metallurgical analysis of isotopes of representative objects from the Cvrtkovci hoard is presented.

Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow artefacts (δ 56 Fe = 0.38 ± 0.1, n = 7) and source materials (δ 56 Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the northeastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data demonstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopically distinct artefacts.

Shear zone-hosted ore bodies at the Balmat, NY, zinc deposit were remobilized at the kilometer scale during amphibolite facies metamorphism ca. 1180 Ma. Despite there being little evidence for interaction of hydrous fluids with ores during deformation, such translocation distances are considered unlikely without the assistance of fluids. Measurements of Zn isotopic composition of sphalerite from six Balmat ore bodies that originated from the same stratigraphic level (Upper Marble unit 6) reveal variation between ore bodies, as well as intra-orebody trends of isotopic lightening down plunge. In general, increasing distance of remobilization correlates with decreasing δ 66 Zn. The syn-tectonic isotopic fractionation recorded in Balmat sphalerite is interpreted to have resulted from the interaction between the ore and sulfide melts that were fluxed by H 2 S localized primarily in Upper Marble unit 7 (fetid dolomite). Lighter isotopes of Zn were enriched in the melt, leaving the residual ore enriched in heavier Zn isotopes. These observations support previous petrographic evidence for the presence of anatectic melts at Balmat and help to explain the unusual scale of translocation at Balmat by means of fluid-assisted remobilization during which intergranular melts decreased rock competency.

Being exclusively placer-based, evidence of
prehistoric tin mining in Europe was erased
rapidly in the fluvial environment. Circumstantial
evidence has suggested that the tin
ores of the Erzgebirge along the German-
Czech border were exploited in the Bronze
Age. To investigate this further, tin ores
from the three Erzgebirge plutons, as well
as Cornwall, were isotopically characterized
and compared with the Sn isotopic composition
of Bronze Age tin-bearing artifacts from
the region. After accounting for isotopic
fractionation associated with the smelting
process, a probabilistic approach indicates
that at the transition to the Middle Bronze
Age, the predominant mining center was the
Central Pluton, but mining activity shifted
to the Western Pluton for the remainder of
the Bronze Age.

The Cross-Cutting zone of the Fowler ore body is one of the many ore bodies of the Balmat, NY massive sulfide zinc deposit that underwent remobilization during upper amphibolite metamorphism and associated deformation. The kilometer-scale remobilization is difficult to reconcile with purely solid-state processes. Given that other polymetallic ores of similar metamorphic grade have been shown to have undergone varying degrees of anatexis, SEM-EDS micro-petrographic analysis of ores was undertaken to determine if melts were present in Balmat ores during metamorphism and deformation. Low melting temperature micro-inclusions of sulfosalt and sulfide assemblages occur predominantly in Qtz-Py and Kfs-Py domains that cross-cut peak metamorphic assemblages. These results indicate that localized anatexis occurred on the prograde path, producing low volumes of melts of varying composition. Polymetallic sulfide melts were initiated by the prograde breakdown of minor phases containing low melting temperature chalcophile elements including As, Sb, Pb, and Cu. Alkaline sili-cate ± carbonate ± sulfide melts were fluxed by halogens, sulfur and other volatile components, released during metamorphism of evaporitic and organic-rich horizons in the marble-dominated host sequence. These low-volume melts and residual fluids would have wetted grain boundaries, affecting the rheology of the bulk ore, and facilitating remobilization of the ores through a combination of solid-and liquid-state processes.

We present a detailed response to the critique by Mr. Jansen of the paper " Digging Deeper: Insights into Metallurgical Transitions in European Prehistory through Copper Isotopes ". When we consider Cu isotope ratios of European Eneolithic and Early Bronze Age artifacts in the context of their local geological settings , climates, and archaeological contexts, Mr. Jansen's hypothesis that 63 Cu enrichment results from the adoption of fahlore ores is untenable. In both Serbia and Central Europe, the earliest copper production is associated with 65 Cu-enriched ores and subsequently produced artifacts yield lower ranges d 65 Cu. This shift in Cu isotopic composition correlates with the initial use of predominantly hypogene ores, not with variations in their trace element content. Essentially the expanded dataset supports the conclusions that were presented in the original paperdCu isotopes are an effective means of delineating the transition from oxide-based smelting to methodologically more complex smelting of sulphide ores in prehistoric Europe with its relatively limited production and trade. Mixing did not mask the critical Cu isotope signatures in this setting. Therefore, Cu isotope compositions of artifacts can be used to interpret the mineralogical character of the ores from which they were produced, regardless of their provenance, as long as trade networks remained within a region of similar climatic history.

The New Jersey Highlands and contiguous Hudson (New York) Highlands host hundreds of small, worked-out mag-netite mines, and the major zinc-oxide deposits of Franklin and Sterling Hill. The origin of the magnetite ore remains controversial. Two temporally distinct genetic models have been proposed for magnetite: (1) a pre-Ottawan, sedimentary exhalative model in which ores were deposited on the seafloor as precipitates from iron-enriched hydrothermal fluids; (2) a late-Ottawan, fluid alteration model in which the current mineral composition of ores was derived from Fe-rich, alkaline fluids, associated with late episodes of granitic plutonism (low-Ti Kiruna-type deposits), or in which deposits derived from metamorphogenic fluids circulating in a regional shear zone leached metals from host rocks and precipitated them in veins and faults. Detailed mapping of ore deposits and host rocks near Wanaque and Ringwood, New Jersey, and Warwick, New York, reveal that ore bodies are hosted by supracrustal rocks deposited in a back-arc basin. At Wanaque and Warwick, ores are strataform and stratabound. Discordant ore bodies at Ringwood are associated with a feeder zone, presumed to have intersected the paleosurface at a steep angle. Sharply layered quartz–diopside gneiss is spatially associated with ore at Wanaque and Warwick, and massive diopsidite is spatially associated with ore at all three locations. Diopsidite in these rocks is nonaluminous, iron enriched, and shares these characteristics with modern metalliferous sediments. Massive diopsidite and quartz–diopside gneiss are interpreted to be metamorphosed carbonate facies iron formation, and associated magnetite to be metamorphosed oxide-facies iron formation. Résumé : Les hautes terres du New Jersey et les hautes terres attenantes de l'Hudson (New York) comptent des centaines de petites mines de magnétite épuisées et les importants gisements d'oxyde de zinc de Franklin et de Sterling Hill. L'origine du minerai de magnétite demeure controversée, deux modèles génétiques distincts sur le plan temporel ayant été proposés, soit (1) un modèle exhalatif sédimentaire pré-ottavien dans lequel les minerais ont été précipités a ` partir de fluides hydrothermaux enrichis en fer sur le fond marin et (2) un modèle d'altération par les fluides tardi-ottavienne dans lequel la composition minérale actuelle des minerais est dérivée de fluides alcalins riches en fer associés a ` des épisodes tardifs de plutonisme granitique (dépôts de type Kiruna pauvres en Ti) ou dans lequel les dépôts découlant de fluides métamorphogènes circulant dans une zone de cisaillement régionale ont lessivé des métaux des roches encaissantes et les ont déposés par précipitation dans des filons et des failles. La cartographie détaillée de gisements de minerai et de roches encaissantes près de Wanaque et Ringwood (New Jersey) et de Warwick (New York) révèle que les corps minéralisés se trouvent dans des roches supracrustales déposées dans un bassin d'arrière-arc. À Wanaque et Warwick, les minerais sont stratiformes et stratoïdes. Des corps minéralisés discordants a ` Ringwood sont associés a ` une zone nourricière dont il est présumé qu'elle recoupait la paléosurface a ` forte inclinaison. Un gneiss a ` quartz–diopside a ` stratification marquée est associé dans l'espace au minerai a ` Wanaque et Warwick, et de la diopsidite massive est associée dans l'espace au minerai aux trois endroits. La diopsidite dans ces roches est non alumineuse et enrichie en fer, des caractéristiques qu'elle partage avec des sédiments métallifères modernes. La diopsidite massive et le gneiss a ` quartz–diopside sont interprétés comme représentant le faciès a ` carbonate de formations de fer métamorphosées et la magnétite associée, comme représentant le faciès a ` oxydes de formations de fer métamorphosées. [Traduit par la Rédaction]

Southeastern Europe is the birthplace of metallurgy, with evidence of copper smelting at ca. 5000 BCE. There the later Eneolithic (Copper Age) was associated with the casting of massive copper tools. However , copper metallurgy in this region ceased, or significantly decreased, centuries before the dawn of the Bronze Age. Archaeologists continue to be debate whether this hiatus was imposed on early metal-working communities as a result of exhaustion of workable mineral resources, or instead a cultural transition that was associated with changes in depositional practices and material culture. Copper isotopes provide a broadly applicable means of addressing this question. Copper isotopes fractionate in the near-surface environment such that surficial oxide ores can be differentiated from non-weathered sul-phide ores that occur at greater depth. This compositional variation is transferred to associated copper artifacts, the final product of the metallurgical process. In the central Balkans, a shift from 65Cu-enriched to 65Cu-depleted copper artifacts occurs across the metallurgical hiatus at the Eneolithic-Bronze Age boundary, ca. 2500 BCE. This indicates that the reemergence of metal production at the beginning of the Bronze Age is associated with pyrotechnical advancements that allowed for the extraction of copper from sulphide ore. Thus copper isotopes provide direct evidence that the copper hiatus was the result of exhaustion of near-surface oxide ores after one-and-a-half millennia of mining, and that the beginning of the Bronze Age in the Balkans is associated with the introduction of more complex smelting techniques for metal extraction from regionally abundant sulphidic deposits.

Increased interest in the fractionation of Sn isotopes has led to the development of several techniques for preparing cassiterite (SnO 2 , the primary ore of Sn) for isotopic analysis. Two distinct methods have been applied in recent isotopic studies of cassiterite: (a) reduction to tin metal with potassium cyanide (KCN) at high temperature (800 °C), with subsequent dissolution in HCl, and (b) reduction to a Sn solution with hydriodic acid (HI) at low temperature (100 °C). This study compares the effectiveness and accuracy of these two methods and contributes additional methodological details. The KCN method consistently yielded more Sn (> 70% in comparison with < 5%), does not appear to fractionate Sn isotopes at high temperatures over a 2-hour period and produced consistent Sn isotope values at flux mass ratios of ≥ 4:1 (flux to mineral) with a minimum reduction time of 40 min. By means of a distillation experiment, it was demonstrated that HI could volatilise Sn, explaining the consistently low yields by this method. Furthermore, the distillation generated Sn vapour, which is up to 0.38‰ per mass unit different from the starting material, the largest induced Sn fractionation reported to date. Accordingly, the HI method is not recommended for cassiterite preparation for Sn isotopic analysis.

Isotopic analysis has proved to be an effective approach to determine the provenance of copper ore sources for the production of bronze artifacts. More recently, methods for Sn isotopic analysis of bronze have been developed. However, the viability of tin isotopes as a means to define groupings that may be attributed to varying ore sources, production methods, or recycling is still in question. In part, this is due to the numerically and/or geographically limited nature of published datasets. This study reports on the Sn isotopic composition of 52 artifacts from the later Bronze Age (1500-1100 BCE) from Serbia and western Romania. The majority of samples cluster between 0.4 and 0.8 per mil for d 124 Sn, and 0.2 and 0.4 per mil for d 120 Sn (relative to NIST SRM 3161A), and this isotopic grouping of bronze artifacts occurs across Serbia. However, groupings of isotopically heavier and lighter artifacts are evident, and each corresponds to a more limited geographic range. Artifacts associated with higher dSn values are limited to the Vojvodina region of northern Serbia, whereas a cluster of bronzes with lower Sn-isotopic signatures are constrained to the Banat along the Serbia-Romania border, and Transylvania. One low-value outlier corresponds to an uncontextualized find near Kru sevac at the southern extent of the study area. Geographic correlation of the low-value cluster with known tin mineralization in Transylvania, and the moderate-value cluster with placer tin deposits of western Serbia, suggests that these distinct bronze Sn-isotopic signatures might reflect exploitation of different tin ores. The small cluster of high Sn-isotopic values from bronzes from the Vojvodina region might reflect bronze recycling in this area that lies furthest from both known tin ore sources.

The Kicking Horse Rim is a linear, fault-controlled, paleotopographic high over which the seaward edge of platformal strata repeatedly developed during the Middle Cambrian. Shale-dominated slope deposits along the Kicking Horse Rim, including the Burgess Shale Formation, contain lenses of black, thin-bedded, non-calcareous, geochemically-anomalous rock composed of &gt;95% F-bearing clinochlore. The lenses show extremely high MgO concentrations (up to 31 wt%). Near the Monarch Pb-Zn mine on Mt Stephen, these rocks are commonly enriched in Pb (up to 247ppm) compared with nearby shale (&lt;12 ppm Pb). The chloritic strata are thinly bedded, and are localized in pods and lenses within paleotopographic lows adjacent to the Cathedral and Eldon escarpments. Syneresis cracks commonly occur in the beds immediately below the chloritic pods. Fossils of low-diversity faunal assemblages are abundant along the rims of the anomalous rocks, whereas fossils of animals are very rare within the chlori...

The Monarch, a mountain in southeastern British Columbia, exposes the Cathedral Escarpment, which abuts the basinal Burgess Shale and an underlying limestone, the upper Takakkaw Tongue. At one section, a dolomitized megabreccia, representing an intraformational collapsed cavern, forms the Cathedral Escarpment wall. The megabreccia is cross-cut by the subsequent megatruncation event marking the collapse of the Cathedral margin, which supports previous hypotheses that dolomitizing brines were active at the Cathedral margin, prior to and during deposition of the Burgess Shale. Epiphyton-rich carbonate megablocks within the basinal strata, previously interpreted as olistoliths spalled off the Escarpment, are unlike the peritidal strata comprising the Cathedral margin and are more likely deep-water carbonate mud mounds that grew in the basin near the Escarpment face. Evidence for early brines in basinal environments at this locality includes lenses of dark, magnesium-rich clinochlore (> 30 wt.% MgO vs ~ 2% in background shales) within the Burgess Shale at the Escarpment wall. These clinochlores are interpreted as precipitates from seafloor brine seeps analogous to ones currently found at the foot of the Florida Escarpment and on the distal shelf and slope of the northern Gulf of Mexico. Like the Gulf examples, the brines formed standing pools on the Cambrian seafloor and hosted abundant organisms in a narrow fringe around their peripheries but not within the pools. Sponges, priapulid worms, hyoliths, linguliform brachiopods and trilobites predominate. Shales only a few metres basinward from the pools are nearly barren of animal fossils. Increased biologic productivity localized at the seeps would account for the patchy distribution of fossils in the Burgess Shale in a narrow zone close to the Escarpment. The discovery of brine seep deposits and associated fringing communities at The Monarch shows that at least some assemblages in the Burgess Shale were preserved within their habitat and were supported by chemosynthesis.

TRUST, or Teacher Renewal for Urban Science Teaching, is a National Science Foundation funded Earth science teacher preparation partnership between the American Museum of Natural History and Brooklyn and Lehman Colleges of the City University of ...

Tin isotopic analysis has been demonstrated to be an effective means by which bronze artifacts may be grouped based on variations in the average isotopic composition of tin ores from which they were manufactured. In the Central Balkans, three geographically distinct groups have been defined: 1) Vojvodina-Transylvania-Central Europe, likely associated with ores from the West Pluton of the Erzgebirge (e.g., Krasno, Horni Slavkov); 2) Central Serbia, with ores sourced from Mt. Cer; and, 3) Southern Serbia-Western Bulgaria originating from an as yet unidentified tin deposit of that is enriched in lighter isotopes of tin.