Iron precipitation in a natural CO2 reservoir: Jurassic Navajo Sandstone in the northern San Rafael Swell,UT, USA

Diagenetic iron (oxyhydr)oxide minerals are common precipitates expected in CO₂ reservoirs, and these minerals record fluid flow for application to carbon capture and sequestration (CSS). Multiple mineralogy and spectroscopy analyses on a pore to meter scale characterize a well‐exposed, lithologically controlled, iron (oxyhydr)oxides reaction front in the Jurassic Navajo Sandstone. Dolomite is the most prevalent cement (up to 23 area%), followed by only several percent or less of iron (oxyhydr)oxides, kaolinite, illite, and gypsum cements. Bulk geochemistry based on diagenetic mineralogies in the reaction front is compared with the water chemistry from nearby modern spring effluent emanating from the Navajo Sandstone to conclude that similar fluids (i.e., CO₂‐charged, saline waters containing hydrocarbons) are responsible for the precipitation. A second comparison of bulk geochemistry and diagenetic mineralogies of the reaction front with data from other abundant Navajo Sandstone concretions in the Spencer Flat region (in south central Utah) shows that reservoir fluids likely vary spatially and temporally in the porous and permeable Navajo Sandstone. CO₂ injection into porous and permeable, quartz arenite, saline aquifers will likely result in minor clay and abundant dolomite precipitation that will significantly decrease porosity.     

Artificial Intelligence, 3D Documentation,and Rock Art—Approaching and Reflecting on the Automation of Identification and Classification of Rock Art Images

Journal of Archaeological Method and Theory - Rock art carvings, which are best described as petroglyphs, were produced by removing parts of the rock surface to create a negative relief. This...     

Structural Adjustment and Subsistence Industry: Artisanal Gold Mining in Ghana

Since the implementation of Ghana's national Structural Adjustment Programme (SAP), policies associated with the programme have been criticized for perpetuating poverty within the country's subsistence economy. This article brings new evidence to bear on the contention that the SAP has both fuelled the uncontrolled growth of informal, poverty‐driven artisanal gold mining and further marginalized its impoverished participants. Throughout the adjustment period, it has been a central goal of the government to promote the expansion of large‐scale gold mining through foreign investment. Confronted with the challenge of resuscitating a deteriorating gold mining industry, the government introduced a number of tax breaks and policies in an effort to create an attractive investment climate for foreign multinational mining companies. The rapid rise in exploration and excavation activities that has since taken place has displaced thousands of previously‐undisturbed subsistence artisanal gold miners. This, along with a laissez faire land concession allocation procedure, has exacerbated conflicts between mining parties. Despite legalizing small‐scale mining in 1989, the Ghanaian government continues to implement procedurally complex and bureaucratically unwieldy regulations and policies for artisanal operators which have the effect of favouring the interests of established large‐scale miners.     

The Stereoscope and Popular Fiction: Imagination and Narrative in the Victorian Home

The stereoscope was a popular parlour toy that provided a powerful psychological viewing experience in the heart of the domestic space. In this article, I consider the stereoscope’s position as an instrument that was experienced, and often represented, in relation to the imaginative narrative processes of memory and fantasy. By reading the stereoscope’s position within popular fiction, the article seeks to uncover the way in which the stereoscope was consumed. The article shows that for many in the mid-Victorian period, the stereoscope operated as an everyday narrative-forming experience with a strong relation to the popular periodical fiction that was read alongside it in the domestic space. The first section of this article considers the cultural and psychological position of the stereoscope within the home, reading this alongside a number of short stories published in the popular periodic press. The second section consists of an analysis of the stereoscope’s involvement with psychological dualism and self-doubling, issues which stem, in particular, from the device’s reliance on photography. These aspects of the device are explored in relation to a nineteenth-century short story which draws a problematic relation between one’s self and one’s portrait. Finally, the article draws these issues together to show the importance of imaginative narratives within the stereoscopic experience. The viewing conditions of the stereoscope encouraged viewers to engage in an anticipatory, open-ended, and imaginative fantasy narrative. It is this unique narrative character of stereoscopic viewing experiences which most prominently distinguishes the device from other visual media.