On some Rock-specimens collected by Dr. Hicks in N.W. Pembrokeshire

1886 ◽  
Vol 42 (1-4) ◽  
pp. 357-363 ◽  
Author(s):  
T. G. Bonney
Keyword(s):  
Rock Specimens

A method to measure pores and fissures in geologic materials under S.E.M. by digital image processing

1978 ◽  
Vol 36 (1) ◽  
pp. 212-213
Author(s):  
L. Montoto ◽  
M. Montoto ◽  
A. Bel-Lan
Keyword(s):  
Image Processing ◽  
Optical Microscopy ◽  
Digital Image Processing ◽  
Digital Image ◽  
Digital Processing ◽  
Free Surfaces ◽  
Geologic Materials ◽  
Automatic Information ◽  
Detector Output ◽  
Rock Specimens

INTRODUCTION.- The physical properties of rock masses are greatly influenced by their internal discontinuities, like pores and fissures. So, these need to be measured as a basis for interpretation. To avoid the basic difficulties of measurement under optical microscopy and analogic image systems, the authors use S.E.M. and multiband digital image processing. In S.E.M., analog signal processing has been used to further image enhancement (1), but automatic information extraction can be achieved by simple digital processing of S.E.M. images (2). The use of multiband image would overcome difficulties such as artifacts introduced by the relative positions of sample and detector or the typicals encountered in optical microscopy.DIGITAL IMAGE PROCESSING.- The studied rock specimens were in the form of flat deformation-free surfaces observed under a Phillips SEM model 500. The SEM detector output signal was recorded in picture form in b&w negatives and digitized using a Perkin Elmer 1010 MP flat microdensitometer.

Evolution of stress-strain state in structured rock specimens under uniaxial loading

2013 ◽  
Vol 49 (5) ◽  
pp. 677-690 ◽  
Author(s):  
V. N. Oparin ◽  
O. M. Usol’tseva ◽  
V. N. Semenov ◽  
P. A. Tsoi
Keyword(s):  
Strain State ◽  
Uniaxial Loading ◽  
Stress Strain ◽  
Stress Strain State ◽  
Rock Specimens

II.—Further Notes on the Petrography of South Georgia

1916 ◽  
Vol 3 (10) ◽  
pp. 435-441 ◽  
Author(s):  
G. W. Tyrrell
Keyword(s):  
East Coast ◽  
The South ◽  
South Georgia ◽  
South Eastern ◽  
North East ◽  
The North ◽  
New Material ◽  
Rock Specimens

The new material on which this paper is based has lately been received through Mr. D. Ferguson, who recently investigated the geology of the island, and collected the rocks described in an earlier paper. It consists of twenty-seven rock specimens from the south-eastern end of the island, between Cape Disappointment and Cooper Island, and nine specimens from Gold Harbour on the north-east coast between Cooper Island and Royal Bay. All these were collected by the staff of the South Georgia Co., Ltd., under the instructions of Mr. Th. E. Salvesen, managing director, of Leith.

Effect of nonlinear elasticity on loading diagrams of rock specimens

2019 ◽  
Author(s):  
Yu. P. Stefanov ◽  
A. S. Romanov ◽  
R. A. Bakeev
Keyword(s):  
Nonlinear Elasticity ◽  
Rock Specimens

Mineralogy and geochemistry of an Archean tuffaceous exhalite: the Main Contact Tuff, Millenbach mine area, Noranda, Quebec

1989 ◽  
Vol 26 (1) ◽  
pp. 88-105 ◽  
Author(s):  
Stavros I. Kalogeropoulos ◽  
Steven D. Scott
Keyword(s):  
Trace Elements ◽  
Hydrothermal System ◽  
The Other ◽  
Mine Area ◽  
The North ◽  
Metalliferous Sediment ◽  
Multiple Input ◽  
Variable Contribution ◽  
Rock Specimens ◽  
Kuroko Deposits

The Main Contact Tuff, in the vicinity of Millenbach mine, Noranda, Quebec, is an extensive, although discontinuous, ore-related volcanic exhalative metalliferous sediment, or "tuffaceous exhalite," of Archean age. It was formed by the variable contribution of two constituents: (1) exhalite (chemical) composed mainly of pyrite, quartz, sphalerite, pyrrhotite, and chalcopyrite and (2) tuff (clastic) composed of quartz, chlorite, and sericite.Tuffaceous exhalites such as the Main Contact Tuff and the similar tetsusekiei of the Japanese Kuroko deposits (Miocene age) indicate a fossil hydrothermal system that may or may not have produced economic concentrations of metallic sulfides. The Main Contact Tuff displays cryptic variations, which provide exploration guides at different scales: (1) the Fe/[Fe + Mg] ratios of chlorite decrease from 0.63 to 0.32 over a distance of 0.3 km approaching ore from the north, and from 0.72 to 0.32 over 1.5 km from the south; (2) the FeO/[FeO + MgO] (sulfide-free) ratios of whole-rock specimens decrease from about 0.8 to 0.3 approaching the ore; (3) ilmenite is replaced in the ore zone by rutile and (or) sphene; and (4) the most manganiferous ilmenite is found close to ore. On the other hand, trace elements of exhalative origin (e.g., Ag, Co) in the Main Contact Tuff appear not to provide useful vectors towards ore. They are concentrated relative to normal pelagic rocks, but their distributions with respect to ore are complicated by multiple input sources and postexhalative redistributions of elements.

Seismic Loss Mechanisms

Geophysics ◽  
1981 ◽  
Vol 46 (5) ◽  
pp. 806-808 ◽  
Author(s):  
N. C. Dutta
Keyword(s):  
Wave Attenuation ◽  
Dynamic Properties ◽  
Petroleum Industry ◽  
Seismic Energy ◽  
Seismic Wave Attenuation ◽  
Seismic Loss ◽  
Research Workshop ◽  
Rock Specimens ◽  
Made In ◽  
Loss Mechanisms

In the petroleum industry there is considerable current interest in understanding the causes of seismic energy loss. During the past few years, considerable progress has been made in the field of seismic wave attenuation as a result of both controlled laboratory studies of the static and the dynamic properties of rock specimens and theoretical modeling. During the 49th Annual International Meeting of the Society of Exploration Geophysicists in New Orleans, a research workshop on Seismic Loss Mechanisms was organized. The purpose of this workshop was to assess current understanding of the physical processes that cause attenuation of seismic energy. The workshop, organized by Kenneth Larner of Western Geophysical and the author, featured a multispeaker format involving invited papers from both industry and academia. The presentations were followed by discussions lasting approximately 90 minutes which included the speakers, the audience, and a panel of experts in the field of seismology.

scholarly journals Dynamic Indentation Characteristics for Various Spacings and Indentation Depths: A Study Based on Laboratory and Numerical Tests

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jie Liu ◽  
Wen Wan ◽  
Yu Chen ◽  
Jun Wang
Keyword(s):  
Crack Propagation ◽  
Laboratory Tests ◽  
Indentation Depth ◽  
Numerical Study ◽  
Stress Concentrations ◽  
Dynamic Indentation ◽  
Indentation Force ◽  
Numerical Tests ◽  
Crack Tips ◽  
Rock Specimens

Laboratory and numerical study tests were conducted to investigate the dynamic indentation characteristics for various spacings and indentation depths. First, laboratory tests indicate that the increase in the indentation depth first resulted in enlarged groove volumes, caused by fiercer rock breakages between indentations for a fixed spacing; then, the groove volume slightly increased for further increase in indentation depth, whereas the increase in spacing restrained rock breakages and resulted in shrunken grooves. In addition, the numerical study agreed well with laboratory tests that small chips formed at the shallow part of the rock specimen at the early indentation stage, and then, larger chips formed by the crack propagation at deeper parts of the rock specimens when the indentation depth increased. With further increase in indentation depth, crushed powders instead of chips formed. Moreover, the numerical analysis indicates that crack propagation usually leads to the decrease of the indentation force and the dissipation of the stress concentrations at crack tips, whereas the cessation of crack propagation frequently resulted in the increase of the indentation force and the stress concentrations at crack tip with the increase in indentation depth.

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