S-type granites in the western Superior Province: a marker of Archean collision zones

2019 ◽  
Vol 56 (12) ◽  
pp. 1409-1436 ◽  
Author(s):  
Xue-Ming Yang ◽  
Derek Drayson ◽  
Ali Polat
Keyword(s):  
Partial Melting ◽  
Melting Process ◽  
Granulite Facies ◽  
Source Rocks ◽  
Crustal Thickening ◽  
Superior Province ◽  
Partial Melting Process ◽  
High K ◽  
Geochemical Variations ◽  
Tectonic Boundary

Detailed field observations indicate that Neoarchean S-type granites were emplaced along and (or) proximal to some terrane (tectonic) boundary zones in the western Superior Province, southeastern Manitoba. These S-type granites are characterized by the presence of at least one diagnostic indicator mineral, such as sillimanite, cordierite, muscovite, garnet, and tourmaline. They are medium- to high-K calc-alkaline, moderately to strongly peraluminous (ANKC >1.1), and contain >1% CIPW normative corundum. Compared with more voluminous, older I-type granitoids in tonalite–trondhjemite–granodiorite suites in the region, the S-type granites occur as relatively small intrusions and have high (SiO2 >72 wt.%) contents with a small silica range (SiO2 = 72.2–81.2 wt.%), but a large range of Zr/Hf (17.1–43.8) and Nb/Ta (0.3–16.0) ratios. These geochemical characteristics suggest that the S-type granites were derived from partial melting of heterogeneous sedimentary rocks deposited as synorogenic flysch that underwent burial and crustal thickening during terrane collision. Although the S-type granites display geochemical variations in individual and between different plutons, their low Sr (<400 ppm) and Yb (<2 ppm) contents and low Sr/Y (<40) and La/Yb (<20) ratios are consistent with a partial melting process that left a granulite-facies residue consisting of plagioclase, pyroxene, and ± garnet. The S-type granites display low zircon saturation temperatures (mostly <800 °C) and low emplacement pressures (<300 MPa), similar to strongly peraluminous leucogranites formed in the Himalayas. Therefore, we propose that the Neoarchean S-type granites in the western Superior Province, whose source rocks were deposited between colliding tectonic blocks between 2720 and 2680 Ma, may serve as a geological marker of some Archean terrane boundary zones.

scholarly journals Intensive Improvement of Cementite Synthesis

2020 ◽  
Vol 5 (2) ◽  
pp. 218-220
Author(s):  
Amir Peyman Soleymani ◽  
Masoud Panjepour ◽  
Mahmood Meratian
Keyword(s):  
Mechanical Properties ◽  
Mechanical Activation ◽  
Carbon Content ◽  
Partial Melting ◽  
Melting Process ◽  
Free Carbon ◽  
Partial Melting Process

Cementite extraordinary mechanical properties have drawn the attention of researchers in recent years. But, the limited methods for the production of this material, led to the production of iron with more than 2.1%wt carbon content beside free carbon by simultaneous thermal-mechanical activation of hematite and graphite mixture at 800°C for 6 hours in the present research. Then, a structure with more than 80%wt cementite was obtained through partial melting process at 1180°C for 25 minutes.

scholarly journals Strongly Peraluminous Granites across the Archean–Proterozoic Transition

2019 ◽  
Vol 60 (7) ◽  
pp. 1299-1348 ◽  
Author(s):  
Claire E Bucholz ◽  
Christopher J Spencer
Keyword(s):  
Partial Melting ◽  
Sedimentary Rock ◽  
Source Rocks ◽  
Crustal Thickening ◽  
Metasedimentary Rocks ◽  
Isotope Data ◽  
Source Regions ◽  
Peraluminous Granites ◽  
Rock Record ◽  
Sedimentary Source

Abstract Strongly peraluminous granites (SPGs) form through the partial melting of metasedimentary rocks and therefore represent archives of the influence of assimilation of sedimentary rocks on the petrology and chemistry of igneous rocks. With the aim of understanding how variations in sedimentary rock characteristics across the Archean–Proterozoic transition might have influenced the igneous rock record, we compiled and compared whole-rock chemistry, mineral chemistry, and isotope data from Archean and Paleo- to Mesoproterozoic SPGs. This time period was chosen as the Archean–Proterozoic transition broadly coincides with the stabilization of continents, the rise of subaerial weathering, and the Great Oxidation Event (GOE), all of which left an imprint on the sedimentary rock record. Our compilation of SPGs is founded on a detailed literature review of the regional geology, geochronology, and inferred origins of the SPGs, which suggest derivation from metasedimentary source material. Although Archean and Proterozoic SPGs are similar in terms of mineralogy or major-element composition owing to their compositions as near-minimum melts in the peraluminous haplogranite system, we discuss several features of their mineral and whole-rock chemistry. First, we review a previous analysis of Archean and Proterozoic SPGs biotite and whole-rock compositions indicating that Archean SPGs, on average, are more reduced than Proterozoic SPGs. This observation suggests that Proterozoic SPGs were derived from metasedimentary sources that on average had more oxidized bulk redox states relative to their Archean counterparts, which could reflect an increase in atmospheric O2 levels and more oxidized sedimentary source rocks after the GOE. Second, based on an analysis of Al2O3/TiO2 whole-rock ratios and zircon saturation temperatures, we conclude that Archean and Proterozoic SPGs formed through partial melting of metasedimentary rocks over a similar range of melting temperatures, with both ‘high-’ and ‘low-’temperature SPGs being observed across all ages. This observation suggests that the thermo-tectonic processes resulting in the heating and melting of metasedimentary rocks (e.g. crustal thickening or underplating of mafic magmas) occurred during generation of both the Archean and Proterozoic SPGs. Third, bulk-rock CaO/Na2O, Rb/Sr, and Rb/Ba ratios indicate that Archean and Proterozoic SPGs were derived from partial melting of both clay-rich (i.e. pelites) and clay-poor (i.e. greywackes) source regions that are locality specific, but not defined by age. This observation, although based on a relatively limited dataset, indicates that the source regions of Archean and Proterozoic SPGs were similar in terms of sediment maturity (i.e. clay component). Last, existing oxygen isotope data for quartz, zircon, and whole-rocks from Proterozoic SPGs show higher values than those of Archean SPGs, suggesting that bulk sedimentary 18O/16O ratios increased across the Archean–Proterozoic boundary. The existing geochemical datasets for Archean and Proterozoic SPGs, however, are limited in size and further work on these rocks is required. Future work must include detailed field studies, petrology, geochronology, and constraints on sedimentary source ages to fully interpret the chemistry of this uniquely useful suite of granites.

Preparation of the textured Bi-based oxide tapes by partial melting process

1991 ◽  
Vol 27 (2) ◽  
pp. 1254-1257 ◽  
Author(s):  
J. Kase ◽  
T. Morimoto ◽  
K. Togano ◽  
H. Kumakura ◽  
D.R. Dietderich ◽  
...  
Keyword(s):  
Partial Melting ◽  
Melting Process ◽  
Partial Melting Process

Spectroscopic determination of thermodynamic parameters in partial melting process of RNA

1999 ◽  
pp. 269-270
Author(s):  
Takashi S. Kodama ◽  
Yoshiyuki Tanaka ◽  
Miyo Morita ◽  
Takashi Yura ◽  
Yoshimasa Kyogoku ◽  
...  
Keyword(s):  
Partial Melting ◽  
Thermodynamic Parameters ◽  
Melting Process ◽  
Spectroscopic Determination ◽  
Partial Melting Process

Optimization of Partial Melting Process for Bi-2212 Multi-Filament Wires

2015 ◽  
Vol 44 (3) ◽  
pp. 563-566
Author(s):  
Zhang Shengnan ◽  
Li Chengshan ◽  
Hao Qingbin ◽  
Lu Tianni
Keyword(s):  
Partial Melting ◽  
Melting Process ◽  
Partial Melting Process

High performance fluorine-free MOD YBa2Cu3O7-z film preparation by partial melting process

2012 ◽  
Vol 513 ◽  
pp. 610-614 ◽  
Author(s):  
W.T. Wang ◽  
Y. Zhao ◽  
M.H. Pu ◽  
X.F. Yang ◽  
H. Zhang ◽  
...  
Keyword(s):  
Partial Melting ◽  
High Performance ◽  
Melting Process ◽  
Partial Melting Process ◽  
Film Preparation

Differential partial melting process for temporal variations of Shandong basalts revealed by melt inclusions and their host olivines

2017 ◽  
Vol 49 ◽  
pp. 205-221 ◽  
Author(s):  
Yin-Hui Zhang ◽  
Zhong-Yuan Ren ◽  
Lu-Bing Hong ◽  
Yan Zhang ◽  
Le Zhang ◽  
...  
Keyword(s):  
Partial Melting ◽  
Melt Inclusions ◽  
Melting Process ◽  
Temporal Variations ◽  
Partial Melting Process

Crustal melt granites and migmatites along the Himalaya: melt source, segregation, transport and granite emplacement mechanisms

2009 ◽  
Vol 100 (1-2) ◽  
pp. 219-233 ◽  
Author(s):  
M. P. Searle ◽  
J. M. Cottle ◽  
M. J. Streule ◽  
D. J. Waters
Keyword(s):  
Partial Melting ◽  
Shear Zone ◽  
Internal Heat ◽  
Shear Zones ◽  
Source Rocks ◽  
Crustal Thickening ◽  
Main Central Thrust ◽  
Crustal Layer ◽  
Middle Crust ◽  
The Himalaya

ABSTRACTIndia–Asia collision resulted in crustal thickening and shortening, metamorphism and partial melting along the 2200 km-long Himalayan range. In the core of the Greater Himalaya, widespread in situ partial melting in sillimanite+K-feldspar gneisses resulted in formation of migmatites and Ms+Bt+Grt+Tur±Crd±Sil leucogranites, mainly by muscovite dehydration melting. Melting occurred at shallow depths (4–6 kbar; 15–20 km depth) in the middle crust, but not in the lower crust. 87Sr/86Sr ratios of leucogranites are very high (0·74–0·79) and heterogeneous, indicating a 100 crustal protolith. Melts were sourced from fertile muscovite-bearing pelites and quartzo-feldspathic gneisses of the Neo-Proterozoic Haimanta–Cheka Formations. Melting was induced through a combination of thermal relaxation due to crustal thickening and from high internal heat production rates within the Proterozoic source rocks in the middle crust. Himalayan granites have highly radiogenic Pb isotopes and extremely high uranium concentrations. Little or no heat was derived either from the mantle or from shear heating along thrust faults. Mid-crustal melting triggered southward ductile extrusion (channel flow) of a mid-crustal layer bounded by a crustal-scale thrust fault and shear zone (Main Central Thrust; MCT) along the base, and a low-angle ductile shear zone and normal fault (South Tibetan Detachment; STD) along the top. Multi-system thermochronology (U–Pb, Sm–Nd, 40Ar–39Ar and fission track dating) show that partial melting spanned ̃24–15 Ma and triggered mid-crustal flow between the simultaneously active shear zones of the MCT and STD. Granite melting was restricted in both time (Early Miocene) and space (middle crust) along the entire length of the Himalaya. Melts were channelled up via hydraulic fracturing into sheeted sill complexes from the underthrust Indian plate source beneath southern Tibet, and intruded for up to 100 km parallel to the foliation in the host sillimanite gneisses. Crystallisation of the leucogranites was immediately followed by rapid exhumation, cooling and enhanced erosion during the Early–Middle Miocene.

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