An active mantle mechanism for Gondwana breakup

Despite over thirty years of plate tectonic theory, the reasons why supercontinents like Gondwana disintegrate into smaller continents and disperse remain enigmatic. Current ideas mostly involve changes in plate-boundary driving forces (passive mantle hypothesis) in preference to an active plume mechanism, even though mantle plumes were present at most stages of Gondwana breakup. The role of these plumes in the breakup process is uncertain, and ideas vary from the chance unroofing of a pre-existing plume, which only contributed in the production of extensive flood basalts, to plumes that controlled the position of breakup. The magmatic and tectonic record along the proto-Pacific margin of Gondwana indicates that there were important changes in subduction zone forces during the initial stages of Gondwana breakup. However, the absence of subduction along the Neotethyan margin at the time of breakup, together with the fact that the initial rift formed almost at right angles to the active subducting margin, suggest a potential active role for a mantle plume in the initial separation. An active mantle mechanism, involving a very large thermal disturbance or megaplume, may, in contrast to a passive mantle hypothesis, more readily explain the formation and rotation of microplates in the South Atlantic region. It accounts also for the production of unusually large igneous provinces (Chon Aike province in Patagonia, Karoo province in southern Africa, and Ferrar province in Antarctica) just prior to breakup

Client and therapist initial experience of using mindfulness in therapy

Literature has demonstrated the influence of mindfulness practice on both clients and therapists; however, no literature has considered the experience of mindfulness in therapy from both members of the therapeutic dyad. The present study interviewed five separate therapy dyads (n=10) regarding their experience of first using mindfulness in session. Participants, both clients and therapists, had little-to-no experience with mindfulness prior to the study. Interview transcripts were analyzed and common themes were derived. Results indicated that both clients and therapist felt that the practice of mindfulness had an impact on the therapeutic relationship. Furthermore, participants also suggested ways in which therapists may better utilize mindfulness in therapy

VOLCANIC GEOLOGY OF MOUNT EREBUS, ROSS ISLAND, ANTARCTICA

Mount Erebus is an active volcano located on Ross Island, Antarctica, in an intraplate extensional tectonic setting. Reconnaissance geologic mapping has shown Mt. Erebus to be composed predominantly of anorthoclase phonolite lava flows and associated pyroclastic rocks. At the surrounding areas of Fang Ridge, Dellbridge Islands, Turks Head and Cape Barne, the lava flows and various pyroclastic deposits are predominantly intermediate in composition. Most of the lavas from Erebus and surroundings are strongly undersaturated and sodic, forming a continuous differentiation lineage consisting of basanite, Ne-hawaiite, Ne-mugearite, Ne-benmoreite and anorthoclase phonolite. These lavas are termed the Erebus lineage (EL) and are predominantly coarsely porphyritic with a similar phenocryst assemblage consisting of olivine, clinopyroxene, opaque oxides, feldspar, apatite and rare feldspathoids.EL lavas are distinctly different from the lavas of the three predominantly basanite volcanic centers which radially surround Mt. Erebus (DVDP lineage; P.R. KYLE : J. Petrol., 22,451,1981), and must have a different petrogenesis. Very minor volumes of less undersaturated benmoreite, phonolite and trachyte occur on Mt. Erebus and must also have evolved independently of the EL