Basin architecture and thermal maturation in the strike-slip Deer Lake Basin, Carboniferous of Newfoundland     

RICHARD S. Hyde  HUGH G. Miller  RICHARD N. Hiscott  JAMES A. Wright 《Basin Research》1988,1(2):85-105

Abstract The Deer Lake Basin is an entirely non-marine basin associated with the Cabot fault zone. Structural and stratigraphic evidence strongly suggest dextral strike-slip movements along the fault zone during Tournaisian-Visean time. Two elongated, end-on structural blocks (probable positive flower structures) contain fold axes and second-order faults oriented obliquely to fault traces bounding the blocks, in a manner implying dextral movements. In one part of the basin, the stratigraphic thickness of a long homoclinal section of later basin-fill sediment (Deer Lake Group) greatly exceeds the suggested depth to basement based on gravity measurements, a situation common to strike-slip basins. Formations representing basin fill can be arranged into megasequences (from oldest to youngest: Anguille Group, Wetstone Point and Wigwam Brook Formations, Deer Lake Group, Howley Formation) corresponding to lateral growth stages of the basin. Gravity, magnetic, and seismic data show that depths to basement on either side of the end-on flower structures are comparable, so that the youngest strata in the basin (Howley Formation) are not underlain by earlier basin fill. These geophysical data, therefore, corroborate the geological conclusion of onlapping stratigraphic relations. The geophysical data suggest participation of basement in Carboniferous gravity faulting and show the location of the subsurface extension of the Taylors Brook Fault in the western part of the Deer Lake Basin. Thermal maturation of the Anguille and Deer Lake Groups, as measured by vitrinite reflectance, clay mineral assemblages, illite crystallinity, and Rock-Eval pyrolysis, indicate a much higher level of maturation for the Anguille than for the Deer Lake Group. Palaeotemperatures for the Anguille and Deer Lake Groups are estimated to be around 200 and 100^oC, respectively, suggesting that Anguille Group rocks are overmature whereas Deer Lake Group strata are within the oil-generating window. Onlapping stratigraphic relations and areally homogeneous time/temperature effects, however, have created a situation in which the Deer Lake Group and Howley Formation have similar maturation levels.  相似文献   

Stable carbon isotopic evidence for climate change across the late Pleistocene to early Holocene from Lesotho,southern Africa     

P. ROBERTS  J. A. LEE‐THORP  P. J. MITCHELL  C. ARTHUR 《第四纪科学杂志》2013,28(4):360-369

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Low-O18 Igneous Rocks from the Intrusive Complexes of Skye, Mull, and Ardnamurchan, Western Scotland     

TAYLOR  HUGH P.  JR.; FORESTER  RICHARD W. 《Journal of Petrology》1971,12(3):465-497

Oxygen isotope analyses have been obtained on rocks and coexistingminerals from the Tertiary stocks, ring-dikes, and cone-sheetsin Ardnamurchan (18 samples), Skye (41 samples), and Mull (18samples); these include a few samples of the plateau basaltcountry rocks. Almost all of the rocks in the vicinity of thecentral ring complexes (within 2 mi. of an intrusive contact)are strongly depleted in O¹⁸ relative to ‘normal’igneous rocks from other areas. The rocks in Skye ( 150 sq.mi.) and Mull ( 150 sq. mi.) have suffered an overall O¹⁸ depletionof about 6 to 7 per mil, and those in Ardnamurchan ( 30 sq.mi.) about 3 to 6 per mil. These data indicate that very large hydrothermal convectionsystems involving heated low. O¹⁸ meteoric ground waters wereestablished in these areas at the time of igneous intrusion.The heated ground waters exchanged with the gabbros, granities,and basaltic lavas, locaclly lowering their O¹⁸/ O¹⁶ rationsby at least 12 per mil. Much, if not all, of this exchange occurredafter crystallization of a given igneous rock was essentiallycomplete, inasmuch as feldspars invariably have undergone muchmore depletion in O¹⁸ than has coexisting quartz or pyroxen.The meteoric-hydrothermal process and the presence of an aqueousgas phase may possibly be responsible for the widespread epidote-chloritealteration, the turbid or cloudy feldspars, the abundant feldspathicveins, the felsitic and granophyric textures, the miaroliticcavities, and much of the explosive volcanic activity and brecciationthat are found in these areas.  相似文献   

Britain's oldest rocks     

HUGH ROLLINSON 《Geology Today》1997,13(5):185-190

In August 1994, Britain's top science journal, Nature, announced that a team of scientists working at the University of Cambridge had found Europe's oldest rocks at a remote location near to Gruinard Bay in the Scottish Highlands. They reported ancient volcanic rocks with an age of 3300 million years. This was more than 300 million years older than any age previously measured on rocks in the British Isles and between 100 and 200 million years older than any rocks known in Europe. The discovery of itself is in many ways unremarkable, for much older rocks are known from ancient continental shield areas in Canada, Australia and Greenland. What was important was that the reported age did not agree with any of the other measured ages known within the British Isles. This was highlighted in a comment in the same issue of Nature, which suggested that the new data were so important that they require a massive revision of our views on the earliest history of the British Isles. For other scientists, however, the conflict between these new data and previously reported ages began to raise questions about the methods employed in dating the 'oldest rocks'.  相似文献   

The Glasgow Garden Festival*     

HUGH PRUDDEN 《Geology Today》1989,5(1):14-15

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The history of coal prospecting in Britain — a neglected subject     

HUGH TORRENS 《Geology Today》1986,2(2):57-58

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The economic evaluation of implementing a GIS     

HOLLY J. DICKINSON  HUGH W. CALKINS 《International journal of geographical information science》2013,27(4):307-327

Abstract

Implementation of geographical information systems (GIS) involves a substantial commitment of resources by the sponsoring agency. Economic evaluation of the proposed GIS is an important step in the implementation process. This article discusses the traditional benefit cost analysis and suggests alternative approaches which may prove useful in situations where the benefit cost model may not be appropriate. A case study of an actual implementation of a GIS which illustrates the approaches discussed is also presented.  相似文献   

BRECCIAS DEPOSITED BY MASS FLOW IN THE BRECCIA NAPPE OF THE FRENCH PRE-ALPS     

HUGH E. HENDRY 《Sedimentology》1972,18(3-4):277-292

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An Indicator of Our Pressure on the Land: New Zealand's Ecological Footprint     

KATHRYN B. BICKNELL  RICHARD J. BALL  ROSS CULLEN  HUGH R. BIGSBY 《New Zealand geographer》1998,54(2):4-11

Sustainability has become a primary goal for much of the legislation which governs resource management in New Zealand. A major difficulty associated with sustainable development objectives, however, is the absence of reliable indicators to measure progress towards the goal of sustainability. The ‘ecological footprint’ provides an estimate of the amount of ecologically productive land required on a continuous basis to sustain current levels of resource consumption and waste assimilation for a given population. By comparing the ecological footprint of a community with the amount of land available, we can more clearly determine whether our current consumption patterns are likely to be sustainable. This paper explores the use of ecological footprint analysis within a New Zealand context. Modifications to the existing procedure for calculating an ecological footprint are proposed, and estimates based on the modified procedures are presented for New Zealand.  相似文献   

The birth of the continents: new clues from inclusions in diamonds     

HUGH ROLLINSON 《Geology Today》1995,11(6):223-225

Tiny inclusions found in diamonds may hold the clue to the origin of the Earth's continental crust. This is the new idea proposed by a group of Earth scientists from Australia and Russia studying a diamond pipe in Siberia.  相似文献