Tectonic structures related to thrusting of ophiolitic complexes: the White Hills Peridotite, Newfoundland

1982 ◽  
Vol 19 (4) ◽  
pp. 709-722 ◽  
Author(s):  
J. Girardeau
Keyword(s):  
Low Temperature ◽  
High Stress ◽  
Metamorphic Rocks ◽  
Tectonic Structures ◽  
Ophiolite Complex ◽  
Fine Grained ◽  
Thrust Plane ◽  
Basal Portion ◽  
Ophiolitic Complex

The White Hills Peridotite and its underlying metamorphic rocks represent the basal portion of a partly eroded ophiolitic complex. At the contact with the metamorphic rocks, the peridotites display low-temperature–high-stress mylonitic textures, which grade upwards to fine-grained porphyroclastic textures indicative of higher temperatures and lower stresses. Petrological and structural evidence indicates that the mylonitic peridotites and underlying metamorphic rocks have been deformed during the oceanic thrusting of the lithosphere. The analysis of the main tectonic structures observed in the peridotites shows that the complex has been thrust northwestward along a southeast-dipping thrust plane. The data are compared with those obtained from the Bay of Islands ophiolite complex.

Mise en place et pétrologie du granite associé au complexe ophiolitique de Thetford Mines, Québec

1984 ◽  
Vol 21 (10) ◽  
pp. 1114-1125 ◽  
Author(s):  
Roger Laurent ◽  
Mehmet F. Taner ◽  
Jean Bertrand
Keyword(s):  
Low Temperature ◽  
Mineral Assemblage ◽  
Shear Zones ◽  
Low Pressure ◽  
Late Ordovician ◽  
Calc Alkaline ◽  
Ophiolite Complex ◽  
Serpentinized Peridotite ◽  
Thrust Plane

Sheets of granite are confined to shear zones in the tectonite peridotite unit of the Thetford Mines ophiolite complex. Their orientation is parallel to the thrust plane at the base of the complex. The granite, which is calc-alkaline and rich in potassium, does not belong to the ophiolite sequence. We show that it was tectonically incorporated within the partially serpentinized peridotite during thrusting and emplacement of the complex.During this process, the granite was strongly deformed and recrystallized at low pressure (500 bar (50 MPa)) and low temperature (500 °C or less), which gave rise to the mineral assemblage orthoclase, albite, hydromuscovite, and hydrothermal biotite. This episode was followed by a rodingite alteration, characterized by the formation of grossular, which was associated with the development of economic chrysotile within the enclosing peridotite. The K–Ar ages of biotite, muscovite, and feldspar from the granite cluster around 450 Ma. These cooling ages suggest that the emplacement and alteration of the granite and peridotite had ended by Late Ordovician time.

TEM/AEM characterization of fine-grained clay minerals in very-low-grade rocks: Evaluation of contamination by empa involving celadonite family minerals

1996 ◽  
Vol 54 ◽  
pp. 694-695
Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi
Keyword(s):  
Electron Microscopy ◽  
Volcanic Rocks ◽  
Analytical Electron Microscopy ◽  
Metamorphic Rocks ◽  
New Mineral ◽  
Chemical Compositions ◽  
Low Grade ◽  
Fine Grained ◽  
Depth Analysis ◽  
Mineral Aggregates

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.

TRI-MARK TM-811N2

Alloy Digest ◽  
1983 ◽  
Vol 32 (4) ◽  
Keyword(s):  
Low Temperature ◽  
High Strength ◽  
Heat Treating ◽  
Low Alloy Steels ◽  
Nickel Steel ◽  
Fine Grained ◽  
Subzero Temperatures ◽  
Steel Weld Metal ◽  
Alloy Steels ◽  
Welding Electrode

Abstract TRI-MARK TM-811N2 is a flux-cored welding electrode for all position semiautomatic arc welding. It is designed to weld 2-3% nickel steels for applications requiring good toughness at subzero temperatures; in addition, it is used to weld various other high-strength low-alloy steels and various fine-grained steels with low-temperature toughness. Tri-Mark TM-811N2 is used to deposit typically 2.35% nickel steel weld metal with good low-temperature impact properties. It is used for shipbuilding, oil rigs and similar structures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: SA-389. Producer or source: Tri-Mark Inc..

Rate Dependent Constitutive Equations of Cyclic Softening

1985 ◽  
Vol 40 (7) ◽  
pp. 653-665
Author(s):  
J. S. Mshana ◽  
A. S. Krausz
Keyword(s):  
Stress Relaxation ◽  
Low Temperature ◽  
Constitutive Equations ◽  
Strain Softening ◽  
Structural Characteristics ◽  
High Stress ◽  
Cyclic Strain ◽  
Cyclic Stress ◽  
Cyclic Softening ◽  
Stress Softening

Constitutive equations of cyclic strain and stress softening for materials with low internal stress levels are derived from the rate theory. The study shows that over the high stress and low temperature range where the description of plastic flow in cyclic softening can be approximated with activation over a single energy barrier, cyclic strain softening is well related to stress relaxation process while cyclic stress softening is related to creep process. The material structural characteristics for cyclic strain softening, cyclic stress softening and stress relaxation are identical. Subsequently, it is shown that cyclic stress and strain softening within the high stress and low temperature range can be evaluated from the constitutive equations using the material structural characteristics measured from a simple stress relaxation test.

Low-Temperature Fine-Grained Alumina?Aluminum Titanate Composites Produced from a Titania-Coated Alumina Precursor

2007 ◽  
Vol 90 (10) ◽  
pp. 3091-3094 ◽  
Author(s):  
Jayasankar Mani ◽  
Solaiappan Ananthakumar ◽  
Poothayil Mukundan ◽  
Krishna Gopakumar Warrier
Keyword(s):  
Low Temperature ◽  
Aluminum Titanate ◽  
Fine Grained

Graded-Density Reservoirs for Accessing High Stress Low Temperature Material States

2007 ◽  
pp. 269-272
Author(s):  
Raymond F. Smith ◽  
K. Thomas Lorenz ◽  
Darwin Ho ◽  
Bruce A. Remington ◽  
Alex Hamza ◽  
...  
Keyword(s):  
Low Temperature ◽  
High Stress
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