Clam growth-stage profiles as a measure of harvest intensity and resource management on the central coast of British Columbia

Examination of growth-stage profiles of shells from nine Northwest Coast shell midden sites shows a majority of senile-stage shells at longer-term residential sites and a majority of mature-stage shells at shorter-term encampments. This pattern indicates less intensive harvest in the vicinity of residential sites, which is consistent with management and conservation of resources for anticipated future needs. Consideration of environmental and taphonomic factors does not account for the observed inter-site variability. Shellfish conservation in the vicinity of residential sites is evident for the period of the past 7000 years.     

A hydrogeologic model of stratiform copper mineralization in the Midcontinent Rift System, Northern Michigan, USA

This paper presents a suite of two‐dimensional mathematical models of basin‐scale groundwater flow and heat transfer for the middle Proterozoic Midcontinent Rift System. The models were used to assess the hydrodynamic driving mechanisms responsible for main‐stage stratiform copper mineralization of the basal Nonesuch Formation during the post‐volcanic/pre‐compressional phase of basin evolution. Results suggest that compaction of the basal aquifer (Copper Harbor Formation), in response to mechanical loading during deposition of the overlying Freda Sandstone, generated a pulse of marginward‐directed, compaction‐driven discharge of cupriferous brines from within the basal aquifer. The timing of this pulse is consistent with the radiometric dates for the timing of mineralization. Thinning of the basal aquifer near White Pine, Michigan, enhanced stratiform copper mineralization. Focused upward leakage of copper‐laden brines into the lowermost facies of the pyrite‐rich Nonesuch Formation resulted in copper sulfide mineralization in response to a change in oxidation state. Economic‐grade mineralization within the White Pine ore district is a consequence of intense focusing of compaction‐driven discharge, and corresponding amplification of leakage into the basal Nonesuch Formation, where the basal aquifer thins dramatically atop the Porcupine Mountains volcanic structure. Equilibrium geochemical modeling and mass‐balance calculations support this conclusion. We also assessed whether topography and density‐driven flow systems could have caused ore genesis at White Pine. Topography‐driven flow associated with the Ottawan orogeny was discounted because it post‐dates main‐stage ore genesis and because recent seismic interpretations of basin inversion indicates that basin geometry would not be conductive to ore genesis. Density‐driven flow systems did not produce focused discharge in the vicinity of the White Pine ore district.     

When the Giant Falls: Endurance and Adaptation at Çadır Höyük in the Context of the Hittite Empire and Its Collapse

At the end of the Late Bronze Age, around 1200 b.c., the Hittite Empire of Anatolia collapsed. While that collapse has been well studied, the effects on Hittite-held lands are less so, with many archaeologists positing an abandonment in Hittite territories for a period of time early in the Iron Age. Recent excavations at Çad?r Höyük, 70 kilometers from the Hittite capital, have revealed both typical Hittite material culture belonging to the Late Bronze Age, including mass-produced ceramics and massive fortifications, as well as evidence suggesting that the site’s residents faced challenges, and adapted accordingly, in the wake of Hittite withdrawal and collapse, during the Early Iron Age. The architecture, ceramics, and zooarchaeological evidence from this rural settlement suggest ways in which residential continuity, cultural resilience, and technological and economic adjustments allowed inhabitants to survive and rebound in the face of political instability.     

Geochemical characterization of ochre from central coastal British Columbia,Canada

The use of ochre and its presence in archaeological contexts is well documented archaeologically, ethnographically and historically. Elemental analysis of ochre is becoming increasingly common as a method for identifying ancient quarrying and mining practices, and for identifying patterns of resource use, trade and exchange. As this type of work has become more common it has become apparent that two critical issues need to be considered: (1) the need for systematic identification of trends and patterns in ochre geochemistry using appropriate statistical analyses, and, (2) consideration of geographic and geologic scale in relation to ochre chemistry. Because ochre is a heterogeneous material relative to other raw material types, it is necessary to apply multivariate and discriminant statistics to differentiate geochemical groups within a sample set. However, caution must be taken when interpreting statistical results at face value. Local geologic and geomorphologic conditions play a significant role in ochre chemistry and need to be taken into account when interpreting analytical results. The purpose of this project was to determine if geochemically distinct groups of ochre could be distinguished through neutron activation analysis (NAA) of archaeological and geological ochres from the central coast of British Columbia, Canada. The results show that it is possible to satisfy the provenance postulate and to differentiate chemical groups through elemental characterization and using multivariate statistical methods.