Search

Eastern Australia encompasses the longest track (~2000 km) of age-progressive continental volcanoes on Earth. These so-called 'central volcanoes' are shield volcanoes considered as surficial expressions of Cenozoic mantle plume activity under the northward moving Australian continent. Here, we investigate three central volcanoes located in the southern, younger part of the volcanic track (Ebor, Nandewar, and Canobolas) with the aim of unraveling the plumbing system architecture during waning hotspot activity. We explore the duration of volcanic activity and compare long-term evolution of magmatic processes via 40Ar/39Ar geochronology, mineral and groundmass chemistry, mineral-melt thermobarometry, and Rhyolite-MELTS thermodynamic simulations. 40Ar/39Ar geochronology on groundmass and mineral separates indicates that Ebor is the oldest of the three volcanoes, with duration of at least ~1 Ma (20.4 ± 0.09 to 19.4 ± 0.07 Ma). Nandewar also lasted ~1 Ma (19.4 ± 0.03 to 18.5 ± 0.03 Ma). The Canobolas volcanic complex was younger and shorter lived at ~0.5 Ma (12.0 ± 0.02 to 11.55 ± 0.05 Ma). Interestingly, all three volcanoes share a repetitive tempo of ~0.1 Ma between eruptions. The volcanoes produced porphyritic to aphyric lavas with basalt to trachyte compositions. The phenocryst assemblage includes plagioclase and K-feldspar, pink and green clinopyroxene, rare olivine, and titanomagnetite. Textural and compositional zoning of phenocrysts reveals successive events of mafic replenishment and magma transport prior to eruption. Dissolution textures in plagioclase, coupled with increasing An and FeOt and decreasing Ba and Ce from crystal cores to mantles, indicate recharge with mafic, oxidised melt. Increasing Mg# and Cr from clinopyroxene cores to rims also supports primitive magma replenishment. Mineral–melt thermobarometry and Rhyolite–MELTS simulations indicate a main level of magma storage in the three volcanoes in the middle crust (18–25-km depth; ~1100°C), repeatedly replenished by undegassed, primitive melts. Green clinopyroxene cores crystallised in isolated pockets where magmas underwent extensive fractionation at depths of 15 to 30 km and ~800°C. The shallow level plumbing system was volumetrically minor and dominated by crystallisation of low-An plagioclase with large melt inclusions, possibly crystallised from degassed, reduced and evolved magma, as suggested by plagioclase hygrometry and fO2 modelling. Our combined geochronological and geochemical approach reveals that the three spatially separated but genetically linked volcanoes had comparable, complex plumbing system architectures. Fractionation and repeated magma rejuvenation were critical processes throughout the lifespans of volcanism, and eruptive tempos were controlled by recurrent mafic influx. The maficity of lavas and their crystal cargo correlate with the volume fraction of phenocrysts, suggesting mafic recharge was a key driver of mush remobilisation and eruption. Other volcanoes active during the late stages of plume activity in eastern Australia share similar textural and geochemical features, suggesting that waning hotspot activity may result in increased complexity in magma transport and storage. [ABSTRACT FROM AUTHOR]

Eastern Australia hosts a long track of Cenozoic age-progressive volcanoes, mostly alkaline in composition. Of these, Warrumbungle and Comboyne are coeval and occur at the same latitude (31°S), but they are ∼300 km apart, on either side of the Great Dividing Range. The lavas from both volcanoes often contain complex crystal assemblages, including plagioclase, olivine and clinopyroxene, which permit a comparative study of pre-eruptive magma histories in a large, complex, continental setting. Here we combine mineral and whole-rock geochemistry with 40Ar/39Ar geochronology to temporally constrain the processes operating in the magma plumbing systems. 40Ar/39Ar geochronology indicates that volcanic activity took place for ∼3 Myr, in two separate stages. The first stage (18–17·5 Ma) is evident only at the larger Warrumbungle volcano. In Stage 2 (∼17–15·5 Ma) the two volcanoes were active contemporaneously. The dominantly porphyritic and relatively evolved (MgO from 7·25 to 0·39 wt %) nature of the lavas suggests that the magmas stalled and differentiated in the crust prior to eruption. At the Warrumbungle volcano, Stage 1 magmas fractionated olivine and minor clinopyroxene and subsequently differentiated during ascent. The crystal cargo in Stage 2 magmas at the Warrumbungle volcano became increasingly more complex with time and the samples have been divided into two subgroups, according to age and petrological variation. Stage 2.1 magmas sampled olivine, clinopyroxene and plagioclase mushes at Moho depths of ∼41 km. Disequilibrium textures in plagioclase and clinopyroxene macrocrysts indicate differences in composition between the mush and the ascending magmas. Stage 2.2 magmas, by contrast, carried a combination of antecrysts and phenocrysts. Clinopyroxene antecrysts show strong disequilibrium textures and are reversely zoned. In plagioclase, anorthite contents increase close to the rim of the crystals, to levels (An60–55) similar to those found at the core of primitive, normally zoned, euhedral antecrysts (An53–50). At the Comboyne volcano mineral phases have a similar complexity to those of Stage 2.2 at the Warrumbungle volcano, with disequilibrium textures and reversely zoned antecrysts providing evidence of magma mixing, only lacking the primitive, normally zoned, euhedral plagioclase crystals. The complex crystal assemblage evident in Stage 2.2 lavas at the Warrumbungle volcano and throughout Stage 2 at the Comboyne volcano indicates a coeval rejuvenation of evolving crystal–melt mushes with the intrusion of more primitive, hotter, and crystal rich or -poor magmas shortly before eruption. Forward modelling using Rhyolite-MELTS replicates the composition of melts and fractionated minerals along a polybaric fractional crystallization path at depths from 24 to 7 km at the Warrumbungle volcano and from 15 to 7 km at Comboyne, supported by barometry estimates on clinopyroxene crystals. This study has identified that the two temporally associated, but spatially discrete, continental alkaline volcanoes were fed by parallel plumbing systems, which become more complex throughout the life of the volcanoes. Multiple mush zones, in which magmas stagnated and fractionated, were periodically replenished with more primitive magmas, triggering eruptions intermittently over a protracted period of ∼3 Myr. [ABSTRACT FROM AUTHOR]

Introduction: Introduction: Sexual health is a central dimension of overall health and quality of life, yet it remains a largely neglected component in vulnerable populations such as cancer patients. Colorectal cancer (CRC) is currently one of the most prevalent types of cancer worldwide, and its treatments negatively affect people's sexual and relational health and well-being throughout the course of the disease. Notwithstanding the negative impact of treatments on different dimensions of sexual functioning (e.g., changes in sexual desire, sexual arousal, and orgasm experience), on the experience of pleasure and sexual satisfaction of people with CRC, access to specialized support is often hampered due to organizational, geographical, and attitudinal barriers (e.g., stigma). Given their intimate nature, accessibility, and convenience/flexibility, smartphone-based digital interventions can help bridge this gap and be an important supportive tool to effectively address unmet sexual health care needs in people with CRC. However, there is still a lack of studies evaluating the acceptability, feasibility, and effectiveness of smartphone-based sexual health promotion programs for people with CRC. Objective: Objectives: The objective of this study is to evaluate the acceptability, feasibility, and preliminary efficacy of Anathema, a program developed for the promotion of the sexual health of CRC survivors. Methods: Methods: A randomized controlled pilot study is underway and involves 30 CRC survivors randomly assigned to an experimental group (with access to the program) and a waiting list control group (treatment as usual). The program was structured into five modules to be completed in 8 weeks and developed based on the principles of Cognitive-Behavioral Therapy. An institutional Ethical Board approved the study. Acceptability, usability, and feasibility of Anathema were the primary outcomes defined in this study. Sexual and relational satisfaction, sexual functioning and distress, sexual pleasure, and quality of life were defined as secondary outcomes. Results: Results: The participatory design used throughout the different phases of this project anticipates a good acceptability of the program among its primary users. It is also expected that the program and the design adopted will be suitable for the future implementation of an RCT. Improvement in levels of sexual and relationship satisfaction, sexual pleasure, quality of life, and a decrease in levels of sexual distress in people who use the program compared to people in the waiting list group, are also expected. Conclusions: Conclusions: Anathema is a promising program for promoting sexual health and quality of life in CRC survivors. Funding source: This project is jointly funded by the European Commission through the AAL Program (ref. AAL-2020-7-133-CP) and its Member States: Fundação para a Ciência e a Tecnologia, in Portugal (AAL/0005/2020), Austrian Research Promotion Agency (FFG), in Austria, and ZonMw, the Netherlands Organization for Health Research and Development, in the Netherlands. Disclosure: No. [ABSTRACT FROM AUTHOR]