Distribution of nickel,copper and zinc in the volcanic series of Erta'Ale,Ethiopia

NI, Cu and Zn were measured polarographically in 34 samples of volcanic rocks from the chain of Erta'Ale, Ethiopia. In this chain all rock types from picritic basalts to alkaline and peralkaline rhyolites can be found. The series is marked by a considerable iron enrichment in the intermediate stages. The distribution of Ni, Cu and Zn in the series emphasizes the efficiency of the crystal-field theory in accounting for the behaviour of the elements during magmatic fractionation. Nickel shows a regular variation throughout the trend. The variation of copper is similar to that of iron, but the relative rates of enrichment and depletion show that they are not necessarily associated with the same mineral phases. The behaviour of Zn is rather irregular.     

Baroclinic oscillations of tidal frequency at ocean weather station P

Abstract

We analyse time series records of isopleth depths derived from two extended sequences of hourly and bi‐hourly sampled profiles taken at Ocean Weather Station P during the summers of 1961 and 1969. Vertical displacements to 240‐m depth are mainly of semidiurnal frequency with r.m.s. amplitudes of 1–4 m. Displacements at diurnal and near‐inertial frequencies are typically less than a metre and have little statistical significance. Within the semidiurnal band, motions appear to be predominantly at the principal solar (S₂) rather than the principal lunar (M₂) semidiurnal frequency. The phase of the M₂ baroclinic tide is roughly equal to that of the M₂ barotropic tide (as extrapolated from coastal and seamount observations); phases of other constituents differ appreciably from barotropic values.     

Health and nutrition in the Pacific islands: Development or underdevelopment?

Although modernization has undoubtedly brought about significant improvements in and access to modern health services and has lowered the previously high incidence of some infectious diseases and perinatal deaths, there is increasingly widespread evidence that some old and some new, often very serious health and nutritional problems still exist in all parts of the often “Edenized” Pacific islands. Although “development” has occurred, both infectious and non-communicable degenerative diseases, perinatal mortality, and nuclear pollution still constitute major health problems, and food systems, nutritional status, and nutrition-linked health seem to have deteriorated.     

Seasonal warm-water refuge and sanctuary usage by the Florida manatee (Trichechus manatus latirostris) in Kings Bay,Citrus County,Florida

The largest Florida manatee (Trichechus manatus latirostris) aggregation at a natural warm-water site occurs in Kings Bay, Crystal River, FL. In accordance with the Manatee Recovery Plan, manatee protection areas within Kings Bay have been created by the United States Fish and Wildlife Service (USFWS) and the State of Florida including a year-round refuge designation and seven Federal manatee sanctuaries during the winter manatee season (15 November–31 March). Over the last 30 years, an increase in manatee counts has been observed in Kings Bay which has prompted the need to review existing manatee protection measures. Aerial survey data collected between 1983 and 2012 were used to examine the seasonal change in manatee distribution within Kings Bay to assess the effectiveness of current sanctuary sizes and locations. Regression analysis suggested a significant change in manatee abundance among the winter seasons (p < 0.05). The average winter manatee counts increased by 4.81 animals per year over the 30-year period. Spatially explicit maps using geographic information system (GIS) analysis revealed a strong correlation between high manatee density and artesian springs in Kings Bay during the winter seasons. Highest abundances were identified at three locations: King Spring, Three Sisters Springs, and Magnolia Springs, which coincide with preexisting sanctuary designations. Additional coverage is advocated to support the overflow of manatees outside of sanctuary boundaries. As density patterns were not uniform across summer periods, a consideration of additional boat speed regulations is recommended.     

The influence of the Sabatayn Evaporites on the hydrocarbon prospectivity of the Eastern Shabwa Basin, Onshore Yemen

The Shabwa Basin is the northeastern extension of the Marib-Al Jawf-Shabwa system of Mesozoic grabens, located onshore in the Republic of Yemen. An evaporitic sequence with an estimated maximum depositional thickness of 300 metres was deposited during the Tithonian. It is designated the Sabatayn Formation and exerts significant control on most of the play elements in the principal hydrocarbon play systems anticipated in the northeastern part of the basin. Migration of hydrocarbons from pre-salt source rocks into intra-and post-salt reservoirs is restricted by the evaporites. Localised heat flow perturbations introduced by the salt, increase the maturity of post-salt source rocks. Post and intra-salt reservoirs are structured by listric faulting on a salt detachment, salt pillowing due to post-depositional loading, by local salt dissolution and by late folding due to gravity sliding of the post-salt section on a salt detachment. Early dissolution and reprecipitation of salt is responsible for occlusion of porosity in intra-salt clastic reservoirs.     

A preliminary study on the climatic and environmental changes at the turn from pleistocene to holocene in East Asia

This paper examines the regional climatic and environmental changes from the late Pleistocene to middle Holocene in Central-East Asia. A review is made of the published literature that are specific to pelaeoclimate and physical environment in some geographical regions.It is shown that (1) during the late Pleistocene the annual mean temperature was 5°–6° C lower than present in Qinghai-Xizang (Tibet) plateau, 6° to 9° C lower than today in NE China, 6° C lower than today in E China, and 4° C lower than present in Taiwan island; (2) during the middle Holocene, the annual mean temperature was 4° C warmer than present in Qinghai-Xizang (Tibet) plateau, 3° to 4° C warmer than today in NE China, 2° to 3° C warmer than today in Shanghai area, and only 2° to 2.5° C warmer in Taiwan island.     

Patterns of urban settlements in Somalia

In this research paper attempts have been made to analyze the distribution of 68 urban settlements in 14 regions of the country. The value of near-neighbour statistic (R) shows nearly random pattern of urban settlements in some regions and approachingly uniform distribution of urban settlements in other regions. Regional distribution of urban settlements and their growth have been explained in context of region's geographical, economic and industrial frameworks.     

Nature of the crust in Maine,USA: evidence from the Sebago batholith

 Neodymium and lead isotope and elemental data are presented for the Sebago batholith (293±2 Ma), the largest exposed granite in New England. The batholith is lithologically homogeneous, yet internally heterogeneous with respect to rare earth elements (REE) and Nd isotopic composition. Two-mica granites in the southern/central portion of the batholith (group 1) are characterized by REE patterns with uniform shapes [Ce_N/Yb_N (chondrite normalized) = 9.4–19 and Eu/Eu* (Eu anomaly) = 0.27–0.42] and ɛ _Nd(t) = −3.1 to −2.1. Peripheral two-mica granites (group 2), spatially associated with stromatic and schlieric migmatites, have a wider range of total REE contents and patterns with variable shapes (Ce_N/Yb_N = 6.1–67, Eu/Eu* = 0.20–0.46) and ɛ _Nd(t) = −5.6 to −2.8. The heterogeneous REE character of the group 2 granites records the effects of magmatic differentiation that involved monazite. Coarse-grained leucogranites and aplites have kinked REE patterns and low total REE, but have Nd isotope systematics similar to group 2 granites with ɛ _Nd(t) = −5.5 to −4.7. Rare biotite granites have steep REE patterns (Ce_N/Yb_N = 51–61, Eu/Eu* = 0.32–0.84) and ɛ _Nd(t) = −4.6 to −3.8. The two-mica granites have a restricted range in initial Pb isotopic composition (²⁰⁶Pb/²⁰⁴Pb = 18.41–18.75; ²⁰⁷Pb/²⁰⁴Pb = 15.60–15.68; ²⁰⁸Pb/²⁰⁴Pb = 38.21–38.55), requiring and old, high U/Pb (but not Th/U) source component. The Nd isotope data are consistent with magma derivation from two sources: Avalon-like crust (ɛ _Nd>−3), and Central Maine Belt metasedimentary rocks (ɛ _Nd<−4), without material input from the mantle. The variations in isotope systematics and REE patterns are inconsistent with models of disequilibrium melting which involved monazite. Received: 8 December 1995 / Accepted: 29 April 1996