The importance of heating duration for Raman CM thermometry: evidence from contact metamorphism around the Great Whin Sill intrusion, UK

2016 ◽  
Vol 35 (2) ◽  
pp. 165-180 ◽  
Author(s):  
H. Mori ◽  
N. Mori ◽  
S. Wallis ◽  
R. Westaway ◽  
C. Annen
Keyword(s):  
Contact Metamorphism ◽  
Sill Intrusion ◽  
Heating Duration

Whin Sill contact metamorphism in the Cow Green reservoir boreholes, Northern England: evidence for an Upper Teesdale source for the Whin Sill magma

2020 ◽  
Vol 63 (3) ◽  
pp. pygs2019-018
Author(s):  
Douglas Robinson
Keyword(s):  
Strong Support ◽  
Contact Metamorphism ◽  
Content Type ◽  
Definitive Evidence ◽  
Link Type ◽  
Metamorphic Development ◽  
Ground Investigation ◽  
Supplementary Material ◽  
The 1960S ◽  
Sill Intrusion

Contact metamorphism of Carboniferous rocks by the Whin Sill in Upper Teesdale is documented utilizing boreholes drilled in the 1960s ground investigation for the Cow Green reservoir. Hedenbergite, prehnite and datolite are recorded for the first time, and the first analyses for seven contact minerals are presented. Pure limestones are recrystallized into saccharoidal marbles with average calcite grain sizes increasing from <0.1 mm at >20 m from the contact, up to 0.5 mm within 5 m from the contact. Grossular is the most abundant mineral, and along with epidote is recorded over 20 m from the sill contact; all other minerals are restricted to < c. 10 m from the contact. This substantial contact metamorphism around Cow Green is unique in comparison with other boreholes across the Alston Block that have penetrated even thicker leaves of the sill, and for which no contact metamorphic mineral development has been reported. The currently favoured model has the magma sourced from dykes on the southern and northern borders of the Alston Block, but the evidence in support is circumstantial. The contrast in the metamorphic development is definitive evidence that the heat flow linked to the Whin Sill intrusion in the Upper Teesdale area lasted much longer than other areas across the Block, giving strong support to the magma being sourced in this area, rather than from the dykes.Supplementary material: X-ray fluorescence whole rock Sr (ppm) analyses of limestone beds in boreholes 17, 18, 21, 22, 35, 39, 40 and 41 in Table S1, and Electron MicroProbe Analysis of garnet, feldspar, epidote, idocrase, prehnite, pyroxene and chlorite in Table S2 are available at: https://doi.org/10.6084/m9.figshare.c.5077640

scholarly journals The formation conditions of birch tar in oxygen-depleted environments

2021 ◽  
Vol 13 (6) ◽  
Author(s):  
Tabea J. Koch ◽  
Patrick Schmidt
Keyword(s):  
Temperature Interval ◽  
Production Systems ◽  
Technical Skills ◽  
Middle Palaeolithic ◽  
Dry Distillation ◽  
Narrow Temperature Interval ◽  
Glass Tubes ◽  
Formation Conditions ◽  
The Relationship ◽  
Heating Duration

AbstractBirch tar is the oldest manmade adhesive dating back to the European Middle Palaeolithic. Its study is of importance for understanding the cognitive capacities and technical skills of Neanderthals and the aceramic production systems employed in the European Palaeolithic and Mesolithic. Several methods may have been used to make birch tar, the most common proposition being dry distillation in oxygen-depleted atmospheres. One of the major impediments for our understanding of the conditions employed to make Neanderthal birch tar, and ultimately the technique used, is that it remains unknown at which temperatures exactly birch tar forms. The relationship between heating duration and tar formation is also unknown. To address these questions, we conduct a laboratory heating experiment, using sealed glass tubes and an electric furnace. We found that birch tar is only produced at a narrow temperature interval (350 °C and 400 °C). Heating times longer than 15 min have no effect on the quantity of tar produced. These findings, notwithstanding previous propositions of necessarily long heating times and larger tolerances for temperature, have important implications for our understanding of the investment in time needed for Palaeolithic birch tar making.

scholarly journals Synthesis of Organic Matter in Aqueous Environments Simulating Small Bodies in the Solar System and the Effects of Minerals on Amino Acid Formation

Life ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 32
Author(s):  
Walaa Elmasry ◽  
Yoko Kebukawa ◽  
Kensei Kobayashi
Keyword(s):  
Amino Acids ◽  
Organic Matter ◽  
Amino Acid ◽  
Solar System ◽  
Acid Formation ◽  
Gel Chromatography ◽  
Small Bodies ◽  
Enhanced Production ◽  
Aqueous Environments ◽  
Heating Duration

The extraterrestrial delivery of organics to primitive Earth has been supported by many laboratory and space experiments. Minerals played an important role in the evolution of meteoritic organic matter. In this study, we simulated aqueous alteration in small bodies by using a solution mixture of H2CO and NH3 in the presence of water at 150 °C under different heating durations, which produced amino acids after acid hydrolysis. Moreover, minerals were added to the previous mixture to examine their catalyzing/inhibiting impact on amino acid formation. Without minerals, glycine was the dominant amino acid obtained at 1 d of the heating experiment, while alanine and β-alanine increased significantly and became dominant after 3 to 7 d. Minerals enhanced the yield of amino acids at short heating duration (1 d); however, they induced their decomposition at longer heating duration (7 d). Additionally, montmorillonite enhanced amino acid production at 1 d, while olivine and serpentine enhanced production at 3 d. Molecular weight distribution in the whole of the products obtained by gel chromatography showed that minerals enhanced both decomposition and combination of molecules. Our results indicate that minerals affected the formation of amino acids in aqueous environments in small Solar System bodies and that the amino acids could have different response behaviors according to different minerals.

scholarly journals Effect of load sequence interaction on bond-wire lifetime due to power cycling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zoubir Khatir ◽  
Son-Ha Tran ◽  
Ali Ibrahim ◽  
Richard Lallemand ◽  
Nicolas Degrenne
Keyword(s):  
High Stress ◽  
Bipolar Transistors ◽  
Junction Temperature ◽  
Experimental Investigations ◽  
Power Cycling ◽  
Power Modules ◽  
Bond Wire ◽  
Load Sequence ◽  
The Difference ◽  
Heating Duration

AbstractExperimental investigations on the effects of load sequence on degradations of bond-wire contacts of Insulated Gate Bipolar Transistors power modules are reported in this paper. Both the junction temperature swing ($$\Delta T_{j}$$ Δ T j ) and the heating duration ($$t_{ON}$$ t ON ) are investigated. First, power cycling tests with single conditions (in $$\Delta T_{j}$$ Δ T j and $$t_{ON}$$ t ON ), are performed in order to serve as test references. Then, combined power cycling tests with two-level stress conditions have been done sequentially. These tests are carried-out in the two sequences: low stress/high stress (LH) and high stress/low stress (HL) for both $$\Delta T_{j}$$ Δ T j and $$t_{ON}$$ t ON . The tests conducted show that a sequencing in $$\Delta T_{j}$$ Δ T j regardless of the direction “high-low” or “low–high” leads to an acceleration of degradations and so, to shorter lifetimes. This is more pronounced when the difference between the stress levels is large. With regard to the heating duration ($$t_{ON}$$ t ON ), the effect seems insignificant. However, it is necessary to confirm the effect of this last parameter by additional tests.

Antigorite-ophicarbonates: Contact metamorphism in Valmalenco, Italy

1977 ◽  
Vol 62 (3) ◽  
pp. 301-312 ◽  
Author(s):  
Volkmar Trommsdorff ◽  
Bernard W. Evans
Keyword(s):  
Contact Metamorphism

Contact metamorphism around the Stawell granite, Victoria, Australia

1994 ◽  
Vol 12 (5) ◽  
pp. 609-624 ◽  
Author(s):  
G. XU ◽  
R. POWELL ◽  
C. J. L. WILSON ◽  
T. M. WILL
Keyword(s):  
Contact Metamorphism

Shale gas leakage in lower Ecca shales during contact metamorphism by dolerite sill intrusions in the Karoo Basin, South Africa

2021 ◽  
Author(s):  
V. Nengovhela ◽  
B. Linol ◽  
L. Bezuidenhout ◽  
T. Dhansay ◽  
T Muedi ◽  
...  
Keyword(s):  
South Africa ◽  
Grain Boundaries ◽  
Shale Gas ◽  
Elevated Temperatures ◽  
Contact Metamorphism ◽  
Microscopy Imaging ◽  
Gas Leakage ◽  
Karoo Basin ◽  
Maximum Temperatures ◽  
Host Rocks

Abstract Contact metamorphism along widespread dolerite sills and dykes, emplaced at 182 to 183 Ma through the sedimentary host rocks of the Karoo Basin, triggered devolatilization of carbon-rich shales of the Lower Ecca Group. Hornfel samples collected from drill cores that intersect dolerite sills were analyzed for mineral phase equilibria, chemistry and porosity to characterize thermal aureoles at various distances from sill intrusions. Andalusite-chiastolite and cordierite porphyroblasts with biotite and muscovite occur within 10 to 20 m of many intrusive contacts. These metamorphic minerals crystallized when host shales attained maximum temperatures ranging between 450 and 600°C. Scanning electron microscopy imaging confirms that the hornfels are compact and that their metamorphic minerals limit porosity along grain boundaries. In few cases intra-mineral porosity occurs within individual crystals such as calcite, andalusite and cordierite. Disequilibrium metamorphic textures such as irregular grain boundaries, and inclusions in andalusite and cordierite reveal that the elevated temperatures were too short-lived to accomplish complete (re)crystallization. Thermal modeling results are consistent with the observed metamorphic mineral assemblages. Gas leakage calculations along a 7 m and a 47 m thick dolerite sill that intrude toward the top of the Whitehill Formation suggest that methane volumes ranging between 8 to 15 Tcf were generated during the sill emplacement. Methane was likely released into the atmosphere through hydrothermal vent complexes that are well preserved in the western Karoo Basin. If such loss was widespread across the entire basin, the implications for paleo-climate change and preserved shale gas reserves in the Karoo Basin of South Africa would be significant.

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