Mixing of brine with oil triggered sphalerite deposition at Pine Point, Northwest Territories, Canada

Hydrocarbons are commonly invoked as triggers for the precipitation of sphalerite in carbonate-hosted Pb-Zn deposits, but direct evidence for the presence of petroleum during sulfide mineralization is rarely documented. Here, we report evidence of fluid mixing between basinal brines and oil during deposition of coarse sphalerite at a classic carbonate-hosted Pb-Zn district, Pine Point, Northwest Territories, Canada. The brines contain high concentrations of Pb, detectable aqueous sulfate, and hydrocarbons that attest to chemical interaction with oil. The oil inclusions in sphalerite contain much less Pb relative to the brines and no evident H2S, suggesting that the principal role of hydrocarbons was as a reductant. Mixing of brine with oil enabled the conversion of aqueous sulfate to sulfide, and thereby triggered sphalerite deposition.

Supplemental Material: Mixing of brine with oil triggered sphalerite deposition at Pine Point, Northwest Territories, Canada

Additional details on methods and results, Tables S1–S4, and Figure S1.<br>

Supplemental Material: Mixing of brine with oil triggered sphalerite deposition at Pine Point, Northwest Territories, Canada

Additional details on methods and results, Tables S1–S4, and Figure S1.<br>

A Folkloristics of Death: Absence, Sustainability, and Ghosts in the Film Welcome to Pine Point

Welcome to Pine Point is a 2011 interactive web documentary about a Canadian town that was physically demolished when the mine closed and residents dispersed. As folklorists, we tend to seek continuation, preservation, sustainability and we see in stories like Pine Point the demise of a folk group in the face of class struggle. “Pine Point” the web video, however, suggests a story and a folk group may be more important in their absence than in their continuation. Putting Welcome to Pine Point into discussion with Jacque Derrida's "hauntology," this chapter explores the preservationism inherent in not only folklore but much of the arts and humanities.

Microsedimentological evidence of vertical fluctuations in subglacial stress from the northwest sector of the Laurentide Ice Sheet, Northwest Territories, Canada

The past-producing Pine Point lead–zinc mining district, Northwest Territories, Canada, provides a unique opportunity to study the role of glacial dynamics in a thick, continuous till succession that has not been influenced by the underlying bedrock topography. Parts of the Pine Point mining district are covered by >20 m of subglacial Quaternary sediments (till) associated with the former Laurentide Ice Sheet. Till facies exposed in unreclaimed open-pit K-62 have been classified into four separate units. Micro- and macrosedimentological analyses were undertaken to identify the change in subglacial stress during sediment deposition and across till unit boundaries. An analysis of high- and low-angle microshears (lineations) in thin sections produced from these till units indicate that there is a noticeable decrease in the abundance of low-angle shear features immediately below till unit boundaries. The deformation of low-angle shears in the underlying tills was likely caused by remobilization of the overlying till unit. This remobilization is consistent with aggradation-constant entrainment decay mechanisms for subglacial till emplacement and accretion and subglacial dispersion models.