Pyroclastic deposits and volcanic history of Mayor Island

The emergent summit of Mayor Island, Bay of Plenty, New Zealand, is a peralkaline rhyolite volcano constructed by: a sequence of lava flows, the Tutaretare Rhyolite Formation new; and pyroclastic deposits, the Oira Pyroclastite Formition (new). These 2 formations constitute the Mayor Island Group new. The pyroclastic deposits mantle most of the outer slopes of the island, in places exceeding 100 m in thickness, and also occur interbedded with lava flows of the main cone. The pyroclastics have been informally assigned on the basis of their compositional, welding and textural, and sedimentary structural characteristics to one or other of 15 lithotypes which may be related to particular modes of eruption and emplacement, of both airfall (phreatic, phreatomagmatic, phreatoplinian, and plinian types) and pyroclastic flow (ignimbrite, nuée ardente, and base surge types origins). A sixteenth lithotype comprises epiclastic deposits formed possibly by catastrophic overspill from an ancestral crater lake. Two new radiocarbon dates on logs from the pyroclastic deposits are recorded: (Wk105) 8000 ± 70 years B.P., and (Wk77) 6340 ± 190 years B.P. Recognition of the calcalkaline Rotoehu and possibly Rotoma Ashes on Mayor Island, together with the new radiocarbon dates, enables definition of 8 phases of major volcanic activity, each separated by relatively quiescent periods with erosion and paleosol formation. Volcanism commenced sometime prior to 42 000 years ago and has continued intermittently up to the eruption of the young dome lavas, possibly less than 1000 years ago. At present, only I Mayor Island-derived tephra has been identified on the mainland of the North Island, namely the Tuhua Tephra dated (Wk77) at source as 6340 ± 190 years B .P. However, the character and magnitude of several of the pyroclastic units on Mayor Island is such that recognition of other peralkaline tephras is anticipated in northern North Island

Weighting the Parameters, a Response to Bancel's “Searching for Global Consciousness: A Seventeen Year Exploration”

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Provenance history of a Late Triassic-Jurassic Gondwana margin forearc basin, Murihiku Terrane, North Island, New Zealand: petrographic and geochemical constraints

The Murihiku Terrane in the North Island was a forearc basin adjacent to a volcanic arc along the eastern margin of Gondwana during the Mesozoic. The rocks that infill the basin are mainly volcaniclastic sandstones and mudstones, often turbiditic, with sparse shellbeds, rhyolitic tuffs, carbonaceous sandstones, plant beds, concretionary horizons, and rare thick granitoid-rich conglomerates. Petrographic studies of the rock fragments in the sandstones show that andesites are the dominant lithic type, but there is a wide range of other lithologies, including dacites, rhyolites, ignimbrites, granitoids, quartzofeldspathic mica schists, rare amphibolites, and reworked mudstones and sandstones. The sandstones are texturally and mineralogically immature and suggest deposition relatively close to a source of high relief, undergoing physical rather than chemical weathering in cool- to cold-temperate conditions. Geochemical analyses of 67 whole-rock volcaniclastic sandstones and siltstones indicate that they were derived from an active and dissected volcanic arc in a convergent margin setting built upon relatively thin continental crust. Modal petrographic data and whole-rock geochemistry both confirm that there were systematic variations with time in the composition of clastic material being supplied to the basin. From the Late Triassic to Middle Jurassic, there was a decrease in silicic volcanic material, plutonics, and metamorphics, and an increase in the supply of andesitic detritus. This was followed in the Late Jurassic by a broader range of volcanic detritus, varying from basaltic andesite to rhyolite, which may have been caused by progressive extension of the volcanic arc and thinning of the crust, a precursor to the breakup of Gondwana in the Early-Middle Cretaceous. Comparison with the Southland segment of the Murihiku Terrane in the South Island suggests that there were significant along-arc source variations, with relatively less silicic but greater andesitic and continental crust contributions in the North Island than in Southland. This may be analogous to the modern Taupo-Kermadec arc where there is a south-north along-arc transition from a continental to an oceanic arc

Sphaerodactylus fantasticus

Number of Pages: 8Integrative BiologyGeological Science

The manufacture of monosodium phosphate from wet process acid by amine extraction

Monosodium phosphate (NaH₂PO₄) may be prepared from a mixture of phosphoric acid and sodium chloride on the principle that an amine in organic solution can extract the elements of hydrochloric acid (HCl). This is possible because amines are more selective for hydrochloric than for phosphoric acid. If wet process phosphoric acid is used, the impurities must be separated in some way from the final product. The work described here involves a study of the distribution of phosphoric acid itself, and the impurities trivalent iron and sulphate, between aqueous solutions and kerosene solut ions of the commercial amine Amberlite LA-1. In a countercurrent extraction process, approximately twenty theoretical stages would be needed to reduce the iron concentration to the food grade level. Sulphate is held in the organic phase. Monosodium phosphate can be recovered by stripping the organic phase with a sodium chloride solution. An attempt was made to explain the extraction of phosphoric and sulphuric acids from a mixture. It was found that amine extraction followed a pattern similar to that of gas adsorption, and a modified BET equation gave a fair but not highly accurate fit of the distribution data

The manufacture of monosodium phosphate from wet process acid by amine extraction

Monosodium phosphate (NaH₂PO₄) may be prepared from a mixture of phosphoric acid and sodium chloride on the principle that an amine in organic solution can extract the elements of hydrochloric acid (HCl). This is possible because amines are more selective for hydrochloric than for phosphoric acid. If wet process phosphoric acid is used, the impurities must be separated in some way from the final product. The work described here involves a study of the distribution of phosphoric acid itself, and the impurities trivalent iron and sulphate, between aqueous solutions and kerosene solut ions of the commercial amine Amberlite LA-1. In a countercurrent extraction process, approximately twenty theoretical stages would be needed to reduce the iron concentration to the food grade level. Sulphate is held in the organic phase. Monosodium phosphate can be recovered by stripping the organic phase with a sodium chloride solution. An attempt was made to explain the extraction of phosphoric and sulphuric acids from a mixture. It was found that amine extraction followed a pattern similar to that of gas adsorption, and a modified BET equation gave a fair but not highly accurate fit of the distribution data

In Search of Scientific Regulation: The UHF Allocation Experiment

This paper reports the results of one attempt to introduce an objective, quantitative, scientific mechanism for making allocational regulatory decisions. The case is the allocation of UHF television stations among cities by the Federal Communications Commission. The mechanism is an experiment which is designed to reveal the preferences of the subjects with respect to alternative allocations. Pilot experiments were performed on FCC staff, the purposes of which were to refine the experimental design and instructions and to provide data for comparing different specifications of the final estimated equation. Participating in the final experiment were six FCC commissioners, nine members of the Commission's congressional oversight committee, and eleven members of the staffs of both groups. Data collected from these experiments have been fitted to theoretical stochastic models of qualitative choice behavior to obtain estimates of allocation preferences as a function of market characteristics. These preference functions are then used (a) to check the coherence of preferences across individuals; (b) to examine differences in policy objectives between congressional oversight committees and the regulatory agency; (c) to determine whether individual preferences can be aggregated into a social decision function with normatively compelling properties, such as consistency with individual preferences or majority-rule equilibrium; and (d) to test the sensitivity of committee decisions to voting institutions and alternative agendas

Spectroscopic studies of water and water/regolith mixtures on planetary surfaces at low temperatures

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1980.Microfiche copy available in Archives and Science.Includes bibliographies.by Roger Nelson Clark.Ph.D