Evidence from accreted seamounts for a depleted component in the early Galapagos plume

The existence of an intrinsic depleted component in mantle plumes has previously been proposed for several hotspots in the Pacific, Atlantic, and Indian Oceans. However, formation of these depleted basalts is often associated with unusual tectonomagmatic processes such as plume-ridge interaction or multistage melting at plume initiation, where depleted basalts could reflect entrainment and melting of depleted upper mantle. Late Cretaceous to middle Eocene seamounts that accreted in Costa Rica and are part of the early Galapagos hotspot track provide new insights into the occurrence and nature of intrinsic depleted components. The Paleocene (ca. 62 Ma) seamounts include unusually depleted basalts that erupted on the Farallon plate far from a mid-ocean ridge. These basalts closely resemble Gorgona komatiites in terms of trace element and radiogenic isotope composition, suggesting formation from a similar, refractory mantle source. We suggest that this source may be common to plumes, but is only rarely sampled due to excessive extents of melting required to extract melts from the most refractory parts of a heterogeneous mantle plume

Integrated care at home reduces unnecessary hospitalizations of community-dwelling frail older adults: a prospective controlled trial.

Care of frail and dependent older adults with multiple chronic conditions is a major challenge for health care systems. The study objective was to test the efficacy of providing integrated care at home to reduce unnecessary hospitalizations, emergency room visits, institutionalization, and mortality in community dwelling frail and dependent older adults. A prospective controlled trial was conducted, in real-life clinical practice settings, in a suburban region in Geneva, Switzerland, served by two home visiting nursing service centers. Three hundred and one community-dwelling frail and dependent people over 60 years old were allocated to previously randomized nursing teams into Control (N = 179) and Intervention (N = 122) groups: Controls received usual care by their primary care physician and home visiting nursing services, the Intervention group received an additional home evaluation by a community geriatrics unit with access to a call service and coordinated follow-up. Recruitment began in July 2009, goals were obtained in July 2012, and outcomes assessed until December 2012. Length of follow-up ranged from 5 to 41 months (mean 16.3). Primary outcome measure was the number of hospitalizations. Secondary outcomes were reasons for hospitalizations, the number and reason of emergency room visits, institutionalization, death, and place of death. The number of hospitalizations did not differ between groups however, the intervention led to lower cumulative incidence for the first hospitalization after the first year of follow-up (69.8%, CI 59.9 to 79.6 versus 87 · 6%, CI 78 · 2 to 97 · 0; p = .01). Secondary outcomes showed that the intervention compared to the control group had less frequent unnecessary hospitalizations (4.1% versus 11.7%, p = .03), lower cumulative incidence for the first emergency room visit, 8.3%, CI 2.6 to 13.9 versus 23.2%, CI 13.1 to 33.3; p = .01), and death occurred more frequently at home (44.4 versus 14.7%; p = .04). No significant differences were found for institutionalization and mortality. Integrated care that included a home visiting multidisciplinary geriatric team significantly reduced unnecessary hospitalizations, emergency room visits and allowed more patients to die at home. It is an effective tool to improve coordination and access to care for frail and dependent older adults. Clinical Trials.gov Identifier: NCT02084108 . Retrospectively registered on March 10(th) 2014

Evidence for subaerial development of the Caribbean oceanic plateau in the Late Cretaceous and palaeo-environmental implications

The formation of oceanic plateaus in the Pacific in the Mesozoic has been proposed to create major environmental impacts, including global anoxic events OAE-1 in the Aptian (ca. 120 Ma) and OAE-2 in the Cenomanian–Turonian (ca. 90 Ma). However, our understanding of the formation of these large volcanic systems and their environmental effects are strongly limited by difficulties in accessing them and characterising their volcanic evolution. In particular, it remains significant to determine whether Pacific oceanic plateaus experience a phase of subaerial volcanic activity as this has critical implications in terms of their environmental impacts. Herein we provide the first unequivocal evidence for an emergent volcanic phase of the Caribbean oceanic plateau in the Late Cretaceous. This subaerial phase is evidenced by accreted oceanic sequences in Colombia that include fallout tuffs with accretionary lapilli and lahar deposits. This facies assemblage, recognised for the first time in an oceanic plateau, reflects phreatomagmatic eruptions coeval with subaerial erosion on an oceanic island. This result, combined with previous evidence of subaerial development of the Ontong Java Plateau and Shatsky Rise, suggests that syn-volcanic emergence of oceanic plateaus was common in the Pacific during the Mesozoic. Although temporal and spatial scales of these emergences remain poorly constrained it confirms that emergence of the Caribbean plateau in the Late Cretaceous (ca. 90 Ma) could have actively contributed to atmospheric changes and the establishment of OAE-2. Significantly, emergence of the Caribbean plateau occurred synchronously to the beginning of its tectonic displacement between the Americas. We propose that this unusual volcanic and tectonic evolution led to drastic reduction of the flow of Pacific oxygenated bottom waters into the early Atlantic basin, leading to a series of regional anoxic events previously documented between the Coniacian and Santonian (OAE-3, ca. 89 to 84 Ma). In addition, emergence of the Caribbean Plateau in the early inter-American seaway could have facilitated migration of terrestrial organisms between the Americas in the Late Cretaceous. The formation of the Caribbean plateau had therefore a large range of possible environmental effects, from atmospheric to palaeo-oceanographic and biotic impacts

Geochemistry of volcanic glasses from the Louisville Seamount Trail (IODP Expedition 330): Implications for eruption environments and mantle melting

Volcanic glasses recovered from four guyots during drilling along the Louisville Seamount Trail, southwest Pacific, have been analyzed for major, trace, and volatile elements (H2O, CO2, S, and Cl), and oxygen isotopes. Compared to other oceanic island settings, they are geochemically homogeneous, providing no evidence of the tholeiitic stage that characterizes Hawaii. The degrees and depth of partial melting remained constant over 1–3 Ma represented by the drill holes, and along-chain over several million years. The only exception is Hadar Guyot with compositions that suggest small degree preferential melting of an enriched source, possibly because it erupted on the oldest and thickest lithosphere. Incompatible element enriched glass from late-stage volcaniclastics implies lower degrees of melting as the volcanoes moved off the melting anomaly. Volcaniclastic glasses from throughout the igneous basement are degassed suggesting generation during shallow submarine eruptions (<20 mbsl) or as subaerial flows entered the sea. Drill depths may no longer reflect relative age due to postquench downslope movement. Higher volatile contents in late-stage volcaniclastics indicate submarine eruptions at 118–258 mbsl and subsidence of the edifices below sea level by the time they erupted, or generation in flank eruptions. Glass from intrusion margins suggests emplacement ∼100 m below the surface. The required uplift to achieve these paleo-quench depths and the subsequent subsidence to reach their current depths exceeds that expected for normal oceanic lithosphere, consistent with the Louisville melting anomaly being <100°C hotter than normal asthenosphere at 50–70 Ma when the guyots were erupted. Key Points: - Louisville glasses show remarkable temporal geochemical homogeneity - All recovered Louisville glasses are variably degassed - Louisville melting anomaly was <100°C hotter than normal asthenospher

Promoting low carbon behaviours through personalised information? Long-term evaluation of a carbon calculator interview

The UK needs to accelerate action to achieve its 80 per cent carbon reduction target by 2050 as it is otherwise in danger of lagging behind. A much discussed question in this context is whether voluntary behaviour change initiatives can make a significant contribution to reaching this target. While providing individuals with general information on climate change or low carbon action is increasingly seen as ineffective, some studies argue that personalised information has greater potential to encourage behaviour change. This mixed methods study examines this claim through a longitudinal field experiment which tested the effectiveness of a carbon calculator interview. It finds that the intervention significantly raised awareness of ways in which participants could reduce their carbon footprint. However, this increased awareness did not translate into measurable behaviour changes in relation to home energy and travel. Qualitative analysis shows that participants refer to infrastructural, social and psychological barriers to change. This indicates that more ambitious government and corporate action is required to speed up carbon reductio