Oceanic intraplate explosive eruptions fed directly from the mantle.

Constraining the volatile content of magmas is critical to our understanding of eruptive processes and their deep Earth cycling essential to planetary habitability [R. Dasgupta, M. M. Hirschmann, Earth Planet. Sci. Lett. 298, 1 (2010)]. Yet, much of the work thus far on magmatic volatiles has been dedicated to understanding their cycling through subduction zones. Further, studies of intraplate mafic volcanism have disproportionately focused on Hawaii [P. E. Wieser et al., Geochem. Geophys. Geosyst. 22, e2020GC009364 (2021)], making assessments of the overall role of intraplate volcanoes in the global volatile cycles a challenge. Additionally, while mafic volcanoes are the most common landform on Earth and the Solar System [C. A. Wood, J. Volcanol. Geotherm. Res. 7, 387-413 (1980)], they tend to be overlooked in favor of silicic volcanoes when it comes to their potential for explosivity. Here, we report primitive (olivine-hosted, with host Magnesium number - Mg# 78 to 88%) melt inclusion (MI) data from Fogo volcano, Cabo Verde, that suggest that oceanic intraplate silica-undersaturated explosive eruptions sample volatile-rich sources. Primitive MI (melt Mg# 70 to 71%) data suggest that these melts are oxidized (NiNiO to NiNiO+1) and very high in volatiles (up to 2 wt% CO2, 2.8 wt% H2O, 6,000 ppm S, 1,900 ppm F, and 1,100 ppm Cl) making Fogo a global endmember. Storage depths calculated from these high volatile contents also imply that magma storage at Fogo occurs at mantle depths (~20 to 30 km) and that these eruptions are fed from the mantle. Our results suggest that oceanic intraplate mafic eruptions are sustained from the mantle by high volatile concentrations inherited from their source and that deep CO2 exsolution (here up to ~800 MPa) drives their ascent and explosivity.

Melt inclusion vapour bubbles: the hidden reservoir for major and volatile elements.

Olivine-hosted melt inclusions (MIs) provide samples of magmatic liquids and their dissolved volatiles from deep within the plumbing system. Inevitable post-entrapment modifications can lead to significant compositional changes in the glass and/or any contained bubbles. Re-heating is a common technique to reverse MI crystallisation; however, its effect on volatile contents has been assumed to be minor. We test this assumption using crystallised and glassy basaltic MIs, combined with Raman spectroscopy and 3D imaging, to investigate the changes in fluid and solid phases in the bubbles before and after re-heating. Before re-heating, the bubble contains CO2 gas and anhydrite (CaSO4) crystallites. The rapid diffusion of major and volatile elements from the melt during re-heating creates new phases within the bubble: SO2, gypsum, Fe-sulphides. Vapour bubbles hosted in naturally glassy MIs similarly contain a plethora of solid phases (carbonates, sulphates, and sulphides) that account for up to 84% of the total MI sulphur, 80% of CO2, and 14% of FeO. In both re-heated and naturally glassy MIs, bubbles sequester major and volatile elements that are components of the total magmatic budget and represent a "loss" from the glass. Analyses of the glass alone significantly underestimates the original magma composition and storage parameters.

Epidemiology and clinico-investigative study of organisms causing vaginal discharge.

BACKGROUND: Abnormal vaginal discharge is a common clinical problem in reproductive age group. It is the second most common problem after abnormal uterine bleeding. It is a neglected health problem, most commonly caused due to vulvovaginal candidiasis, trichomoniasis, and bacterial vaginosis (BV). OBJECTIVES: The present study was conducted to determine the prevalence of common organisms causing vaginal discharge and also to know the variety of clinical presentation. MATERIALS AND METHODS: A cross-sectional descriptive study was conducted in the Skin and STD Outpatient Department of Vinayaka Mission Kirupananda Variyar Medical College Hospital, Salem, who presented with abnormal vaginal discharge between September 2012 and September 2014. A total of 100 women in the reproductive age group who had symptoms of vaginitis were examined. Data were coded and analyzed. RESULTS: Out of the 100 patients examined, 77 (77%) cases were organism positive. Among the positive cases, BV (27%) was the most common microbiological cause of abnormal vaginal discharge, followed by trichomoniasis (25%), vaginal candidiasis (22%), combined infection (Candida and BV) (3%), and nonspecific cases (23%). CONCLUSION: Out of 100 cases, few cases showed discordance between clinical and laboratory diagnosis. This discordance can be due to pitfalls in identifying the causative agent clinically or obscuring of the findings due to improper treatment received for other ailments. Thus, clinico-investigative correlation is more important than other clinical findings alone.

Giant seborrheic keratosis of the genitalia with an unusual histopathological finding.

Seborrheic keratosis (SK) of the external genitalia is a rare entity which can be easily misinterpreted as genital warts. Histopathology is a useful tool to make a diagnosis in such cases. We report a 62-year-old male who presented with multiple polypoidal lesions exclusively on the external genitalia. Histopathology was suggestive of hyperkeratotic type of SK which showed some unusual features.