scholarly journals Joint spacings, mineral modes and grain size measurements for selected granitic rocks in the northern Rockies and in southwest England

1990 ◽  
Author(s):  
Judy Ehlen ◽  
E-an Zen
Keyword(s):  
Grain Size ◽  
Granitic Rocks ◽  
Northern Rockies

Holocene climate recorded by magnetic properties of lake sediments in the Northern Rocky Mountains, USA

The Holocene ◽  
2019 ◽  
Vol 30 (3) ◽  
pp. 479-484
Author(s):  
Daniel P Maxbauer ◽  
Mark D Shapley ◽  
Christoph E Geiss ◽  
Emi Ito
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Rocky Mountains ◽  
Future Research ◽  
Magnetic Minerals ◽  
Holocene Climate ◽  
Northern Rocky Mountains ◽  
The North ◽  
Lake Bottom ◽  
Northern Rockies

We present two hypotheses regarding the evolution of Holocene climate in the Northern Rocky Mountains that stem from a previously unpublished environmental magnetic record from Jones Lake, Montana. First, we link two distinct intervals of fining magnetic grain size (documented by an increasing ratio of anhysteretic to isothermal remanent magnetization) to the authigenic production of magnetic minerals in Jones Lake bottom waters. We propose that authigenesis in Jones Lake is limited by rates of groundwater recharge and ultimately regional hydroclimate. Second, at ~8.3 ka, magnetic grain size increases sharply, accompanied by a drop in concentration of magnetic minerals, suggesting a rapid termination of magnetic mineral authigenesis that is coeval with widespread effects of the 8.2 ka event in the North Atlantic. This association suggests a hydroclimatic response to the 8.2 ka event in the Northern Rockies that to our knowledge is not well documented. These preliminary hypotheses present compelling new ideas that we hope will both highlight the sensitivity of magnetic properties to record climate variability and attract more work by future research into aridity, hydrochemical response, and climate dynamics in the Northern Rockies.

Layered Granitic Rocks at Chebucto Head, Halifax County, Nova Scotia

1975 ◽  
Vol 12 (3) ◽  
pp. 456-463 ◽  
Author(s):  
T. E. Smith
Keyword(s):  
Grain Size ◽  
Nova Scotia ◽  
Granitic Rocks ◽  
Textural Characteristics ◽  
Rock Types ◽  
Flow Sorting

Structural, mineralogical and textural characteristics of some layered granitic rocks are described. The layers result from the segregation of minerals into bands and lenses of contrasting color and grain size. They were formed near the roof of the pluton prior to final crystallization by flow sorting during episodic shearing generated during intrusion. Comparison of the mineralogy and textures of the layered rocks with those of the main rock types of the pluton shows that the differentiation of the pluton as a whole took place after the formation of the layers by interaction of felsic components concentrated in residual liquids with earlier formed crystals.

Análise Comparativa entre a Resistência à Tração na Flexão e Compressão da Argamassa Convencional e Argamassa com Adição de Pó de Brita Granítica

2018 ◽  
Vol 21 (3) ◽  
pp. 161
Author(s):  
Jessica Pereira da Silva ◽  
Dahiane Dos Santos Oliveira Zangeski ◽  
Dayane Ferreira Nascimento ◽  
Jonathan Willian Zangeski Novais ◽  
Renata Luisa Ferreira ◽  
...  
Keyword(s):  
Grain Size ◽  
Mass Density ◽  
Raw Material ◽  
Granitic Rocks ◽  
Crushed Stone ◽  
Design Strength ◽  
Environmental Preservation ◽  
Quarry Fines ◽  
Lime Powder ◽  
The Comparative Study

Os finos de pedreira que resultam da britagem de rochas graníticas, geralmente, são descartados e ficam estocados, ocupando áreas desnecessárias em pedreiras e expostas ao vento, chuva. Diante dessa situação, observa-se um desperdício da matéria-prima e visando a preservação ambiental se percebe a alternativa de empregar o pó de brita como agregado artificial em argamassa de revestimento. Para melhor entendimento dessa possibilidade, o artigo referenciou ao estudo comparativo da resistência à compressão e tração entre a argamassa convencional e a argamassa com adição de 20% de pó de brita granítica, confeccionados de acordo com os requisitos solicitados pela NBR 13281. Os dados foram obtidos pela ruptura de 12 corpos de prova cilíndricos e 12 corpos de prova prismáticos, nas idades de 7, 14, 21 e 28 dias, para ambos os tipos de argamassas, que foram dimensionadas com a resistência de projeto de 20 MPa, com o traço em volume para argamassa convencional de 1: 3,2: 0,4 (cimento, areia e cal hidratada) e para argamassa com adição de pó de brita de 1: 2,56: 0,64: 0,4 (cimento, areia, pó de brita e cal). Os resultados comprovaram que a resistência da argamassa com adição de pó de brita granítica se demostrou mais elevada. Palavras-chave: Finos de Pedreira. Granulometria. Densidade da Massa Fresca.AbstractQuarry fines resulting from the crushing of granitic rocks are usually discarded, stored in unnecessary quarry areas and exposed to wind, rain. Faced with this situation, a waste of the raw material is observed and environmental preservation is perceived as the alternative to use the crushed stone powder as an artificial aggregate in coating mortar. For a better understanding of this possibility, the article referred to the comparative study of the compressive strength and tensile strength between the conventional mortar and the mortar with the addition of 20% granite gravel powder, made according to the requirements of NBR 13281. The data were obtained by the rupture of 12 cylindrical specimens and 12 prismatic specimens, at the ages of 7, 14, 21 and 28 days, for both types of mortars, which were dimensioned with a design strength of 20 MPa, (Cement, sand and lime hydrate) and for mortar with addition of crushed stone powder of 1: 2.56: 0.64: 0.4 ( Cement, sand, gravel and lime powder). The results showed that the strength of the mortar with the addition of granite gravel powder was higher.Keywords: Quarry Fines. Grain Size. Fresh Mass Density.

Effect of Grain Size in Granitic Rocks on Hydraulic Fracturing Mechanism

2000 ◽  
Author(s):  
Tsuyoshi Ishida ◽  
Shunji Sasaki ◽  
Isao Matsunaga ◽  
Qu Chen ◽  
Yoshiaki Mizuta
Keyword(s):  
Grain Size ◽  
Hydraulic Fracturing ◽  
Granitic Rocks ◽  
Fracturing Mechanism

Nahan Sandstone and its exfoliation, Nainital District, Uttar Pradesh, India

1971 ◽  
Vol 108 (3) ◽  
pp. 229-234 ◽  
Author(s):  
Brijraj K. Das ◽  
Vanshnarayan
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Uttar Pradesh ◽  
Igneous Rocks ◽  
Granitic Rocks ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Physical Processes ◽  
Fine Grained ◽  
Petrographic Study

SummaryThe Nahan sandstone of the Nainital district is a soft, fine-grained sandstone of subgreywacke type. Like massive igneous rocks it is very well exfoliated and consists of many concentric layers. Petrographic study of different layers of this sandstone, modal analysis, grain size analysis, and size distribution of the various samples, have revealed that physical processes are mainly responsible for exfoliation of the sandstone. The study of various sedimentary parameters indicated that the provenance is from the schistose and granitic rocks of the surrounding Himalayan mountains and the material was deposited in a shallow slowly sinking basin.

Effect of Shock Loading on the Microstructure of Uniloy 326

1974 ◽  
Vol 32 ◽  
pp. 504-505
Author(s):  
K. P. Staudhammer ◽  
L. E. Murr
Keyword(s):  
Grain Size ◽  
Shock Loading ◽  
Current Investigation ◽  
Two Phase ◽  
05 C ◽  
Shock Deformation ◽  
Heat Treated

The effect of shock loading on a variety of steels has been reviewed recently by Leslie. It is generally observed that significant changes in microstructure and microhardness are produced by explosive shock deformation. While the effect of shock loading on austenitic, ferritic, martensitic, and pearlitic structures has been investigated, there have been no systematic studies of the shock-loading of microduplex structures.In the current investigation, the shock-loading response of millrolled and heat-treated Uniloy 326 (thickness 60 mil) having a residual grain size of 1 to 2μ before shock loading was studied. Uniloy 326 is a two phase (microduplex) alloy consisting of 30% austenite (γ) in a ferrite (α) matrix; with the composition.3% Ti, 1% Mn, .6% Si,.05% C, 6% Ni, 26% Cr, balance Fe.

Aspects of microanalysis in a transmission electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 510-511
Author(s):  
R. Sinclair ◽  
B.E. Jacobson
Keyword(s):  
Grain Size ◽  
Electron Beam ◽  
Electron Microscope ◽  
Chemical Analysis ◽  
Transmission Electron Microscope ◽  
Vapor Deposition ◽  
Critical Currents ◽  
X Ray ◽  
Fine Grain ◽  
Transmission Electron

INTRODUCTIONThe prospect of performing chemical analysis of thin specimens at any desired level of resolution is particularly appealing to the materials scientist. Commercial TEM-based systems are now available which virtually provide this capability. The purpose of this contribution is to illustrate its application to problems which would have been intractable until recently, pointing out some current limitations.X-RAY ANALYSISIn an attempt to fabricate superconducting materials with high critical currents and temperature, thin Nb3Sn films have been prepared by electron beam vapor deposition [1]. Fine-grain size material is desirable which may be achieved by codeposition with small amounts of Al2O3 . Figure 1 shows the STEM microstructure, with large (∽ 200 Å dia) voids present at the grain boundaries. Higher quality TEM micrographs (e.g. fig. 2) reveal the presence of small voids within the grains which are absent in pure Nb3Sn prepared under identical conditions. The X-ray spectrum from large (∽ lμ dia) or small (∽100 Ǻ dia) areas within the grains indicates only small amounts of A1 (fig.3).

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