Harold Herbert Read, 1889–1970

Ohne Zusammenfassung

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Harold Herbert Read, 1889–1970

     

The Resolving Power of Gross Earth Data

A gross Earth datum is a single measurable number describing some property of the whole Earth, such as mass, moment of interia, or the frequency of oscillation of some identified elastic-gravitational normal mode. We show how to determine whether a given finite set of gross Earth data can be used to specify an Earth structure uniquely except for fine-scale detail; and how to determine the shortest length scale which the given data can resolve at any particular depth. We apply the general theory to the linear problem of finding the depth-variation of a frequency-independent local Q from the observed quality factors Q of a finite number of normal modes. We also apply the theory to the non-linear problem of finding density vs depth from the total mass, moment, and normal-mode frequencies, in case the compressional and shear velocities are known.     

Evolution des hydrocarbures dans des sédiments côtiers méditerranéens prélevés à proximité d'un emissaire d'une raffinerie de pétrole

Coastal Mediterranean sediments highly polluted by refinery effluents have been studied for their hydrocarbon content and bacterial activity. The study has taken into account both the distance from the refinery and depth of sampling. Very high hydrocarbon concentrations have been found (1–250 g/kg dry sediment). Micro-organisms in the sediments have a high bacterial activity and a good correlation exists between hydrocarbon concentrations and bacteria able to use these substrates as a carbon and energy source.     

Influence of illumination conditions on the sea-bottom visibility

Statistical models of the useful and background signals forming an image of the sea bottom observed through a rough sea surface are constructed. The methods for estimating the signal-to-noise ratio in the image of the bottom with the test distribution of the reflectance are described. The dependence of the signal-to-noise ratio on observational conditions, in particular, on the mutual orientation of the directions of sighting, wind, and solar vertical, is analyzed. Recommendations on the choice of optimal conditions for bottom observations from airborne carriers are given.     

Age and pyrite Pb-isotopic composition of the giant Sukhoi Log sediment-hosted gold deposit, Russia

Sukhoi Log is one of the largest gold deposits in Russia (1100 t Au at 2.45 g/t). Like many other sediment-hosted gold deposits throughout the world, Sukhoi Log preserves textural, structural and geochemical evidence for multiple generations of Au enrichment and pyrite growth.The deposit is located in the Lena gold province of Siberia, on the edge of the Siberian Craton and occurs in the core of a recumbent anticline in a Neoproterozoic black shale and quartz-rich siltstone-sandstone turbidite succession. Temporal constraints on pyrite paragenesis at the deposit have been determined using laser ablation inductively coupled mass spectrometry (LA-ICPMS) measurements of U, Th and Pb isotopes in pyrite, monazite and zircon. LA-ICPMS age determinations on detrital zircons indicate the host rocks were deposited after 600 ± 10 Ma and derived from a mixture of Palaeoproterozoic and Neoproterozoic sources. The U, Th and Pb isotopic systematics indicate the cores of large monazite crystals, which predate obvious tectonic fabric development in the host rocks, began growing at 573 ± 12 Ma. The rims of the same monazite crystals formed at 516 ± 10 Ma, during peak metamorphism and deformation. Small monazite crystals also grew in the sedimentary rocks during the Devonian (374 ± 20 Ma) and the Carboniferous or Early Permian (288 ± 22 Ma), possibly in response to fluid movements triggered by synchronous granite intrusion in the area. Multi-collector and quadrupole LA-ICPMS Pb isotopic determination on pyrite, combined with overprinting criteria, show that the earliest (stratiform) Pb and Au-bearing pyrite formed prior to metamorphism—possibly during sedimentation or early diagenesis (575-600 Ma). Small Au-rich pyrite nodules preserved as cores to folded bedding-parallel pyrite-quartz veins probably grew during late diagenesis or early metamorphism. Large pyrite euhedra, which overgrow the strong axial planar cleavage in the host rocks, have more radiogenic Pb-isotopic compositions and formed either late during or after deformation. Framboidal pyrite that is overgrown by both the late diagenetic-early metamorphic and syn- to post-metamorphic pyrite has the most radiogenic Pb-isotopic composition suggesting exchange with radiogenic Pb in the matrix may have continued until late in the history of the deposit.The dating and Pb isotopes support a multistage origin for the gold deposit with Au first introduced during or prior to growth of the earliest stratiform pyrite and progressively re-concentrated (with or without addition of further gold) during later metamorphic events.     

Social acceptability of a marine protected area: The case of Reunion Island

This paper examines variations in social acceptability of a Marine Protected Area (MPA) prior to implementation. The influence of a number of factors, including socio-economic characteristics, perception of coral resources state of health and attitudes towards non-compliance with regulations are analysed. During May 2006, 640 questionnaires were distributed to school children around Reunion Island, Western Indian Ocean, for completion by their parents, following an informal educational activity made in school. From a 73% (n = 469) response rate, results showed that 78% of participants were in favour of the MPA. Analysis further identified that those supportive of the MPA were generally from higher socio-professional categories, had a negative perception of the coral reef ecosystem's health and were not originally from Reunion. In contrast, locals (born in Reunion) from lower socio-professional categories or with no employment activity and having a positive perception of the health status of coral reefs offered no opinion on the MPA. Attitudes towards enforcement and compliance highlighted that SCUBA divers, fishers and jet skiers attributed a higher value to the protection of the coral reef environment through enforcement of MPA regulations than to their own use of the coral reef resource. When asked about the use of penalties to deter non-compliance, swimmers were awarded the lowest fines, followed by SCUBA divers, fishers then jet skiers being awarded the highest fines. Thus, the more severe the act of non-compliance by a resource user group was perceived to be, the more these users themselves disapproved of non-compliant behaviour and supported use of high penalties. The survey design through focusing on school children's parents, demonstrated a simple and cost-effective method for data collection while providing environmental education, which could be employed in similar case studies elsewhere.