scholarly journals Controls on timing of exhumation and deformation in the northern Peruvian eastern Andean wedge as inferred from low-temperature thermochronology and balanced cross section

Tectonics ◽  
2015 ◽  
Vol 34 (4) ◽  
pp. 715-730 ◽  
Author(s):  
Adrien Eude ◽  
Martin Roddaz ◽  
Stéphanie Brichau ◽  
Stéphane Brusset ◽  
Ysabel Calderon ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Balanced Cross Section

scholarly journals Crystal mush dykes as conduits for mineralising fluids in the Yerington porphyry copper district, Nevada

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Lawrence C. Carter ◽  
Ben J. Williamson ◽  
Simon R. Tapster ◽  
Catia Costa ◽  
Geoffrey W. Grime ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Porphyry Copper ◽  
Similar Type ◽  
Interconnected Network ◽  
Crystal Mush ◽  
Porphyry Deposit ◽  
Hydrothermal Quartz ◽  
Miarolitic Cavities

AbstractPorphyry-type deposits are the world’s main source of copper and molybdenum and provide a large proportion of gold and other metals. However, the mechanism by which mineralising fluids are extracted from source magmas and transported upwards into the ore-forming environment is not clearly understood. Here we use field, micro-textural and geochemical techniques to investigate field relationships and samples from a circa 8 km deep cross-section through the archetypal Yerington porphyry district, Nevada. We identify an interconnected network of relatively low-temperature hydrothermal quartz that is connected to mineralised miarolitic cavities within aplite dykes. We propose that porphyry-deposit-forming fluids migrated from evolved, more water-rich internal regions of the underlying Luhr Hill granite via these aplite dykes which contained a permeable magmatic crystal mush of feldspar and quartz. The textures we describe provide petrographic evidence for the transport of fluids through crystal mush dykes. We suggest that this process should be considered in future models for the formation of porphyry- and similar-type deposits.

Silicate-germanate K2Y[(Si3Ge)O10(OH)] with unusual complex corrugated layer and its correlation to ring silicate gerenite and chain silicate chkalovite

2020 ◽  
Vol 235 (4-5) ◽  
pp. 167-172
Author(s):  
Anastasiia P. Topnikova ◽  
Elena L. Belokoneva ◽  
Olga V. Dimitrova ◽  
Anatoly S. Volkov ◽  
Leokadiya V. Zorina
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Complex Anion ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Chain Silicate ◽  
Novel Complex

AbstractA new silicate-germanate K2Y[(Si3Ge)O10(OH)] was synthesized hydrothermally in a system Y2O3:GeO2:SiO2 = 1:1:2 (T = 280 °C; P = 90–100 atm.); K2CO3 was added to the solution as a mineralizer. Single-crystal X-ray diffraction experiment was carried out at low temperature (150 K). The unit cell parameters are a = 10.4975(4), b = 6.9567(2), c = 15.4001(6) Å, β = 104.894(4)°; V = 1086.86(7) Å3; space group is P 21/c. A novel complex anion is presented by corrugated (Si,Ge) tetrahedral layers connected by couples of YO6 octahedra into the mixed microporous framework with the channels along b and a axes, the maximal size of cross-section is ~5.6 Å. This structure has similarity with the two minerals: ring silicate gerenite (Ca,Na)2(Y,REE)3Si6O18 · 2H2O and chain silicate chkalovite Na2BeSi2O6. Six-member rings with 1̅ symmetry as in gerenite are distinguished in the new layer. They are mutually perpendicular to each other and connected by additional tetrahedra. Straight crossing chains in chkalovite change to zigzag four-link chains in the new silicate-germanate layer.

Multipod ZnO Nanoforms: Low Temperature Synthesis and Characterization

2007 ◽  
Vol 7 (2) ◽  
pp. 689-695 ◽  
Author(s):  
Tandra Ghoshal ◽  
Soumitra Kar ◽  
Subhajit Biswas ◽  
Gautam Majumdar ◽  
Subhadra Chaudhuri
Keyword(s):  
Low Temperature ◽  
Field Emission ◽  
Cross Section ◽  
Thermal Evaporation ◽  
Synthesis And Characterization ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis ◽  
Optical Absorbance ◽  
Higher Temperature ◽  
Emission Studies

ZnO nanotetrapods were synthesized by a simple thermal evaporation of Zn powder at a relatively low temperature ∼600 °C. The tetrapods have four legs with hexagonal cross-section. Interpenetrating growth was observed in some of these nanotetrapods. Multipod ZnO nanoforms were produced at higher temperature. The optical characterizations such as optical absorbance, photoluminescence and Raman spectroscopy reveal excellent crystal qualities of these nanoforms. The field emission studies indicated that these nanoforms could be utilized in field emission based devices.

scholarly journals Examining the tectono-stratigraphic architecture, structural geometry, and kinematic evolution of the Himalayan fold-thrust belt, Kumaun, northwest India

Lithosphere ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 414-435 ◽  
Author(s):  
Subhadip Mandal ◽  
Delores M. Robinson ◽  
Matthew J. Kohn ◽  
Subodha Khanal ◽  
Oindrila Das
Keyword(s):  
Cross Section ◽  
Structural Model ◽  
Kinematic Model ◽  
Thrust Belt ◽  
Main Central Thrust ◽  
Thrust Sheet ◽  
Balanced Cross Section ◽  
Kinematic Evolution ◽  
Thrust Sheets ◽  
Northwest India

Abstract Existing structural models of the Himalayan fold-thrust belt in Kumaun, northwest India, are based on a tectono-stratigraphy that assigns different stratigraphy to the Ramgarh, Berinag, Askot, and Munsiari thrusts and treats the thrusts as separate structures. We reassess the tectono-stratigraphy of Kumaun, based on new and existing U-Pb zircon ages and whole-rock Nd isotopic values, and present a new structural model and deformation history through kinematic analysis using a balanced cross section. This study reveals that the rocks that currently crop out as the Ramgarh, Berinag, Askot, and Munsiari thrust sheets were part of the same, once laterally continuous stratigraphic unit, consisting of Lesser Himalayan Paleoproterozoic granitoids (ca. 1850 Ma) and metasedimentary rocks. These Paleoproterozoic rocks were shortened and duplexed into the Ramgarh-Munsiari thrust sheet and other Paleoproterozoic thrust sheets during Himalayan orogenesis. Our structural model contains a hinterland-dipping duplex that accommodates ∼541–575 km or 79%–80% of minimum shortening between the Main Frontal thrust and South Tibetan Detachment system. By adding in minimum shortening from the Tethyan Himalaya, we estimate a total minimum shortening of ∼674–751 km in the Himalayan fold-thrust belt. The Ramgarh-Munsiari thrust sheet and the Lesser Himalayan duplex are breached by erosion, separating the Paleoproterozoic Lesser Himalayan rocks of the Ramgarh-Munsiari thrust into the isolated, synclinal Almora, Askot, and Chiplakot klippen, where folding of the Ramgarh-Munsiari thrust sheet by the Lesser Himalayan duplex controls preservation of these klippen. The Ramgarh-Munsiari thrust carries the Paleoproterozoic Lesser Himalayan rocks ∼120 km southward from the footwall of the Main Central thrust and exposed them in the hanging wall of the Main Boundary thrust. Our kinematic model demonstrates that propagation of the thrust belt occurred from north to south with minor out-of-sequence thrusting and is consistent with a critical taper model for growth of the Himalayan thrust belt, following emplacement of midcrustal Greater Himalayan rocks. Our revised stratigraphy-based balanced cross section contains ∼120–200 km greater shortening than previously estimated through the Greater, Lesser, and Subhimalayan rocks.

Steel Tube Bending with a Filling Medium of Fiber-Reinforced Ice (FRI)

2016 ◽  
Vol 703 ◽  
pp. 11-16 ◽  
Author(s):  
Takahiro Ohashi
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Steel Tube ◽  
Filling Material ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Tube Bending ◽  
Steel Tubes ◽  
Crushing Strength ◽  
Temperature Melting

This paper proposes a new filling material, fiber-reinforced ice (FRI), for tube bending. In tube bending, lead and low temperature melting alloys have conventionally been utilized as the filling medium to prevent defects and to alleviate flattening of the tube’s cross section. However, these alloys are usually harmful to the environment (e.g., Pb, Bi-Pb-Sn-In, or Pb-Cd system alloys) or are expensive (e.g., In-Sn system alloys). In this study, the author utilized ice reinforced with the fiber of wastepaper for 3-point bending of JIS G 3452 SGP 32A steel tubes. Compression tests were conducted to analyze whether these tubes have crushing strength comparable to that of conventional fillings and sufficient ductility in low-speed deformation. The filling medium with more fiber effectively yielded less flattening.

scholarly journals First measurement of the hydrogen spin-exchange collision cross-section in the low temperature region

2008 ◽  
Vol 48 (3) ◽  
pp. 343-350 ◽  
Author(s):  
C. Baumgarten ◽  
B. Braun ◽  
M. Capiluppi ◽  
G. Ciullo ◽  
P. F. Dalpiaz ◽  
...  
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Temperature Region ◽  
Spin Exchange ◽  
Collision Cross Section ◽  
Exchange Collision
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