The ~AD1315 Tarawera and Waiotapu eruptions, New Zealand: contemporaneous rhyolite and hydrothermal eruptions driven by an arrested basalt dike system?

A series of large hydrothermal eruptions occurred across the Waiotapu geothermal field at about the same (prehistoric) time as the ~AD1315 Kaharoa rhyolite magmatic eruptions from Tarawera volcano vents, 10–20 km distant. Triggering of the Waiotapu hydrothermal eruptions was previously attributed to displacement of the adjacent Ngapouri Fault. The Kaharoa rhyolite eruptions are now recognised as primed and triggered by multiple basalt intrusions beneath the Tarawera volcano. A ~1000 t/day pulse of CO₂ gas is recorded by alteration mineralogy and fluid inclusions in drill core samples from Waiotapu geothermal wells. This CO₂ pulse is most readily sourced from basalt intruded at depth, and although not precisely dated, it appears to be associated with the Waiotapu hydrothermal eruptions. We infer that the hydrothermal eruptions at Waiotapu were primed by intrusion of the same arrested basalt dike system that drove the rhyolite eruptions at Tarawera. This dike system was likely similar at depth to the dike that generated basalt eruptions from a 17 km-long fissure that formed across the Tarawera region in AD1886. Fault ruptures that occurred in the Waiotapu area in association with both the AD1886 and ~AD1315 eruptions are considered to be a result, rather than a cause, of the dike intrusion processes.Editorial responsibility: J. Donnelly-Nolan     

'This is like my comfort zone': Senses of place and belonging within Oruāmo/Beachhaven, New Zealand

Abstract:  This paper examines the culturally specific experiences of belonging within Oruāmo/Beachhaven, a suburb in North Shore City. In-depth interviews with 32 caregivers of young children expose the fact that the ethnic groups represented – Māori, Samoan and Pākehā– vary in their uses and understandings of, as well as feelings for, residential neighbourhood. Examination of the themes of natural environment, social relations, continuity of residence, facilities, organisations and place transformation reveal that, while representatives of all groups had views on these matters, there was a variable degree of engagement with and priority afforded to these concerns.     

Quaternary intraplate deformation in the southeastern Sierras Pampeanas, Argentina

Neogene strain from the subducting Nazca plate is widely distributed in theAndean foreland as a result of flat-lying subduction beneath central westernArgentina (28^°–33^°S latitude). This fact is indicated byuplifted basement blocks bounded by reverse faults as far as 600 kms eastof the Chilean trench axis. Some deformation in the southern Sierras deCórdoba (southeastern Sierras Pampeanas) indicates significantdisplacements during Quaternary and even late Holocene time. Thisregion has low to moderate seismicity characterized by earthquakemagnitudes 6.7 with no associated noticeable surface ruptures.This paper presents information recently gathered on the most conspicuousregional structures of the area (El Molino, Sierra Chica and Las Lagunasfaults). The last movement along the El Molino fault thrust basement rocksover organic-rich (0.8–1.3 ka) sediment and fault relationships suggestprevious Quaternary displacements. Along the Sierra Chica fault,Precambrian basement has been thrust a minimum of 13.5 m overPleistocene conglomerates, and faulting also affects latePleistocene-Holocene fluvial sediments. The Las Lagunas fault has beenregarded as the source of the 1934 Ms 5.5 and 6.0 earthquakes, whichheavily damaged the nearby village of Sampacho. The faulted surface isburied under Holocene loess, but its trace is expressed as a 24-km-longrectilinear scarp, despite continuous modification due to land use.Although we lack detailed information on probable rupture lengths duringlarge Sierras Pampeanas thrust earthquakes, some preliminary considerationsare made for the regional seismic hazard of these structures. The geologicevidence described here identifies these faults as possible sources of strongearthquakes in the future.     

A systematic approach to radiometric and paleomagnetic studies in a mobile orogenic belt: I. The waning phase of activity in the southern Appalachians of South Carolina

The survey of radiometric and paleomagnetic work on the mafic rocks of South Carolina is consistent with, and amplifies the studies on the acidic rocks of the southeast by Ellwood (1982). The westerly post-early Mesozoic tilt of the southeastern Appalachians proposed by Dooley and Smith (1982) over most of the Piedmont balances out the post-late Paleozoic southeastern tilt of Ellwood (1982). Only in the Elberton-Sparta block is the tilting important and here the interpretation proposed is of a greater initial tilt (approximately 25–30°) reduced by the post-early Mesozoic tilt.There is no evidence of displaced terrains as far as the King's Mountain, Charlotte, and Slate belts are concerned at least since 300 m.y. ago and perhaps as early as 350 m.y. ago. The anomalous paleomagnetic data from the Kiokee belt is best interpreted as due to tectonic displacements associated with the late Paleozoic event described by Secor and Snoke (1978) and Snokeet al. (1980).The paleopoles of the mafic rocks are in agreement with paleopoles on the North American apparent polar wander path (APWP) at about 300 m.y. The resolution of K–Ar apparent ages of 350 m.y. or older will require⁴⁰Ar/³⁹Ar studies and such age relationships are critical to the reasonable application of tilt corrections in the southern Appalachians.     

Palaeomagnetic investigations of the tertiary and quaternary igneous rocks: VII the tertiary rocks of Southwest Germany

Rocks from sixteen sites in southwestern Germany were examined palaeomagnetically and petrologically with attention concentrated on the ore minerals. The largest suite of rocks from the Hegau shows that two dated rocks have the sign of magnetization predicted byHeirtzler et al. (1968) and two do not. However the confidence levels of the radiometric ages are not known. It is probable that the remanence found in the Katzenbuckel reflects the time of hydrothermal alteration, the rest, the paleomagnetic field.

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Zusammenfassung Aus dem Bereich des Oberrheingrabens und des Hegaus (SW-Deutschland) wurden Vulkanite entnommen und paläomagnetisch und erzmineralogisch untersucht.Die umfangreiche Gesteinsserie aus dem Hegau zeigt, daß zwei datierte Gesteine der vonHeirtzler et al. (1968) vorhergesagten Magnetisierungsrichtung entund zwei dieser Skala widersprechen. Dabei bleibt offen, inwieweit die beiden Skalen radiometrischer Daten übereinstimmen. Möglicherweise gibt die gefundene Remanenz in den Katzenbuckelgesteinen die Zeit der hydrothermalen Veränderung, der Rest das paläomagnetische Feld wieder.

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Résumé Des échantillons volcaniques, prélevés dans la région du fossé d'Alsace et de Bade ainsi que dans celle du Hegau (Allemagne du sud-ouest) ont fait l'objet d'une analyse paléomagnétique et minéralogique.La série de roches provenant du Hegau montre que 2 roches datées correspondent à la direction d'aimantation indiquée parHeirtzler et d'autres (en 1968), tandis que 2 autres la contredisent. La question de savoir dans quelle mesure les deux échelles de données radiométriques sont concordantes reste entière. Il se peut que l'aimantation rémanente, dans les roches du Katzenbuckel, indique le moment de la transformation hydrothermale, tandis que le reste reflète le champ paléomagnétique.

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- Hegau (- ). Hegau , , Heirtzler'oM ., (1968), , . , , . , Katzenbuckel , — . . . . - . .

     

Military pollution and natural purity: seeing nature and knowing contamination in Vieques, Puerto Rico

Military activities have produced contaminated environments at many sites around the world. This contamination and the associated health risks play a large role in how these places can be redeveloped after military use. In this essay we focus on the island of Vieques, Puerto Rico which was used as a bombing range by the US military for six decades until 2003. We examine the ways different groups of people perceive this formerly militarized landscape and the ways that these perceptions legitimatize certain redevelopment options over others. Through participant observation, semi-structured interviews and an analysis of textual materials we found that many local residents view the island as suffering from severe contamination while the large number of visitors, tourism promoters and North Americans now flocking to the post-militarized Vieques view it quite differently. These perceptions of purity and contamination, affected by different knowledges of the island’s history, have led to differing valuation of the landscape and contentious economic, political, and cultural battles over an island often labeled “natural” despite a history of military use and social exclusion.

Framings and coverage of climate change in Swedish specialized farming magazines

Climate change is a fundamental challenge for which agriculture is sensitive and vulnerable. The Intergovernmental Panel on Climate Change has identified relevant information as key to enabling appropriate climate adaptation and mitigation action. Information specifically directed to farmers can be found, for example, in specialized farming magazines. While recent studies examine how national news media frame climate change, less—if any—studies have addressed climate framings and coverage in specialized media. Media framings are storylines that provide meaning by communicating how and why an issue should be seen as a problem, how it should be handled, and who is responsible for it. This paper analyses the framings and coverage of climate change in two Swedish specialized farming magazines from 2000 to 2009. It examines the extent of the climate change coverage, the content of the media items, and the dominant framings underlying their climate change coverage. The study identifies: increased coverage of climate change starting in 2007; frequent coverage of agriculture’s contribution to climate change, climate change impacts on agriculture, and consequences of climate politics for agriculture; and four prominent frames: conflict, scientific certainty, economic burden, and action. The paper concludes that climate change communicators addressing farmers and agricultural extension officers should pay attention to how these frames may be interpreted by different target audiences. Research is needed on how specialized media reports on climate-related issues and how science-based climate information is understood by different groups of farmers and which other factors influence farmers’ engagement in climate mitigation and adaptation.     

Acceptance of open source geospatial software: Assessing QGIS in South Africa with the UTAUT2 model

Geospatial information and technologies are widely used in South Africa, initially mostly with proprietary software but today, mature, open source alternatives such as QGIS are available. We wanted to find out if and why South African users accepted QGIS, globally the most widely used free and open source GIS. We adapted the extended unified theory of acceptance and use of technology model to test several hypotheses regarding the acceptance and use of QGIS in South Africa. 205 registered members of the Geo‐Information Society of South Africa completed a structured questionnaire. Results show that habit has the most significant influence on behavioural intention to use QGIS, followed by facilitating conditions, price value and social influence. Performance expectancy, effort expectancy, hedonic motivation and access to source code played no significant role. The findings show that adoption of QGIS in South Africa is not primarily influenced by benefits attributed to open source software, such as cost benefits, customizability, improved reliability, quality and security. The results are useful for developers of any GIS product and for choosing a GIS product for an organization, because they provide insight into the behavioural intentions of users.     

Evaluating Light Availability,Seagrass Biomass,and Productivity Using Hyperspectral Airborne Remote Sensing in Saint Joseph’s Bay,Florida

Seagrasses provide a number of critical ecosystem services, including habitat for numerous species, sediment stabilization, and shoreline protection. Ariel photography is a useful tool to estimate the areal extent of seagrasses, but recent innovations in radiometrically calibrated sensors and algorithm development have allowed identification of benthic types and retrieval of absolute density. This study demonstrates the quantitative ability of a high spatial resolution (1 m) airborne hyperspectral sensor (3.2 nm bandwidth) in the complex coastal waters of Saint Joseph’s Bay (SJB). Several benthic types were distinguished, including submerged and floating aquatic vegetation, benthic red algae, bare sand, and optically deep water. A total of 23.6 km² of benthic vegetation was detected, indicating no dramatic change in vegetation area over the past 30 years. SJB supported high seagrass density at depths shallower than 2 m with an average leaf area index of 2.0?±?0.6 m² m^?2. Annual seagrass production in the bay was 13,570 t C year^?1 and represented 41 % of total marine primary production. The effects of coarser spatial resolution were investigated and found to reduce biomass retrievals, underestimate productivity, and alter patch size statistics. Although data requirements for this approach are considerable, water column optical modeling may reduce the in situ requirements and facilitate the transition of this technique to routine monitoring efforts. The ability to quantify not just areal extent but also productivity of a seagrass meadow in optically complex coastal waters can provide information on the capacity of these environments to support marine food webs.