Geology of the Springdale Group: a newly recognized Silurian epicontinental-type caldera in Newfoundland

1987 ◽  
Vol 24 (6) ◽  
pp. 1135-1148 ◽  
Author(s):  
Marylou Coyle ◽  
D. F. Strong
Keyword(s):  
Large Scale ◽  
Basaltic Magma ◽  
Volcanic Rocks ◽  
Sedimentary Facies ◽  
Volcanic Field ◽  
Silica Content ◽  
Large Area ◽  
Basement Rocks ◽  
Iapetus Ocean ◽  
High Silica

Volcanic–sedimentary facies and structural relationships of the Silurian Springdale Group in west-central Newfoundland are indicative of a large collapse caldera with an area of more than 2000 km2. Basaltic flows, andesite flows and pyroclastic rocks, silicic ash-flow tuffs, high-silica rhyolite domes, and volcanically derived debris flows and breccias, fluviatile red sandstones, and conglomerates make up the group. It is bounded on the east and west by up-faulted basement rocks, which include gneisses, amphibolites, and pillow lavas, and in the northwest it unconformably overlies Lower Orodovician submarine volcanics. These margins are intruded by cogenetic and younger granitoid rocks. The volcanic rocks form a calc-alkaline series, although gaps in silica content at 52–56, 67–68, and 73–74% separate them into four groups: basalts, andesites–dacites, rhyolites, and high-silica rhyolites.The high-silica rhyolites are chemically comparable to melts thought to form the upper parts of large, layered silicic magma chambers of epicontinental regions. Such an environment is also suggested by the large area of the Springdale caldera and the fact that it is one of a number of calderas that make up a large Silurian volcanic field in western Newfoundland. An epicontinental tectonothermal environment for central Newfoundland in Silurian–Devonian times is readily explained by the fact that this magmatic activity followed a period of destruction and closure of the early Paleozoic Iapetus Ocean, with trapped heat and basaltic magma causing large-scale melting of thickened and subducted continental crust in an overall transpressional tectonic regime.

The Ash Content of Insects

1931 ◽  
Vol 22 (4) ◽  
pp. 453-457 ◽  
Author(s):  
E. B. Uvarov
Keyword(s):  
Large Scale ◽  
Manganese Content ◽  
Silica Content ◽  
Conclusive Evidence ◽  
Scale Analysis ◽  
Negative Evidence ◽  
Iron Copper ◽  
Large Scale Analysis ◽  
High Silica ◽  
The Difference

In the case of silica, there appears to be a definite variation of SiO2 content with different species. The difference between yellow locusts (6·27 per cent.) and red locusts (14·7 per cent.) is especially marked. It may be attributed to the fact that red locusts are actively feeding, sexually immature adults, and in consequence they consume large amounts of food with a high silica content. The fact that museum specimens of yellow locusts contain a higher percentage of silica than intact yellow specimens indicates that the majority of the silica is not concentrated in the digestive tract. The same appears to apply to the iron content. Copper was found in appreciable quantities in all the insects examined, but no definite conclusion can be drawn from the numerical results, as the variation from batch to batch was too great. The results for manganese are not satisfactory, as in several cases negative evidence was obtained. This is inconsistent with the work of Vinogradov, who obtained conclusive evidence of manganese in insects. In the case of Agonoscelis, however, the manganese content was found to be extraordinarily high (0·47 per cent.), suggesting that it may play a definite physiological part. The presence of a respiratory pigment, pinnaglobin, containing manganese, has been shown in the tropical mussel, but there is as yet no evidence for the presence of this pigment in the insect world.It is impossible, however, to draw any such conclusions from ash analysis results of entire insects only, and systematic analyses of the blood of numerous species will be necessary to establish the presence of the metals iron, copper and manganese, in their respiratory pigments.Definite evidence of nickel (in almost negligible amounts) was shown by the large-scale analysis, but apart from this no element was detected which had not been previously reported.

Petrology and the Western Rift of Central Africa

1932 ◽  
Vol 69 (11) ◽  
pp. 497-510 ◽  
Author(s):  
A. W. Groves
Keyword(s):  
Rift Valley ◽  
Volcanic Rocks ◽  
Central Africa ◽  
Volcanic Field ◽  
Thin Sections ◽  
Basement Rocks ◽  
Geochemical Study ◽  
Northern Half ◽  
Tectonic Significance ◽  
Near Future

IN the course of several journeys between Masindi and Butiaba, and one from Butiaba to Hoima (via Waki Camp), specimens of the various gneisses were collected from roadside exposures. Thin sections of these were subsequently studied by the writer in England with the result that they were found to yield evidence of tectonic significance. In addition, the writer has, during the last three years, examined petrographically a large number of other rocks from those parts of Uganda bordering the Lake Albert Depression. In particular he has made a special study of the Charnockite Series, which are widely spread over the northern half of the Protectorate, with the result that it has been possible to observe the effects of the rift valley movements on these rocks in the regions adjacent to Lake Albert. It is hoped to publish a petrological and geochemical study of the Charnockite Series of Uganda in the near future. In the following pages it is proposed in Part I to present petrological evidence from the basement rocks of various districts in the hinterland of the Lake Albert scarps and then in Part II to point out the tectonic significance of this evidence in the light of the various theories of rift valley formation. In Part III the relation between the petrological characters of the volcanic rocks and the rift valley tectonics will be briefly reviewed. In the case of the basement rocks the remarks will be confined to the Lake Albert Depression, but in the case of the volcanic rocks the discussion will extend also to Lakes George and Edward and the Birunga volcanic field.

Thermal infrared exploration in the Carlin trend, northern Nevada

Geophysics ◽  
1990 ◽  
Vol 55 (1) ◽  
pp. 70-79 ◽  
Author(s):  
Kenneth Watson ◽  
Fred A. Kruse ◽  
Susanne Hummer‐Miller
Keyword(s):  
Physical Properties ◽  
Volcanic Rocks ◽  
Thermal Inertia ◽  
Thermal Infrared ◽  
Silica Content ◽  
Geologic Materials ◽  
Northern Nevada ◽  
Geologic Maps ◽  
High Silica ◽  
First Time

Experimental Thermal Infrared Multispectral Scanner (TIMS) aircraft data have been acquired for the Rodeo Creek NE 7 1/2 minute quadrangle, Eureka County, northern Nevada, covering the Carlin gold mine. A simple model has been developed to extract spectral emissivities for mapping surface lithology and alteration based on the physical properties of geologic materials. Emissivity‐ratio images were prepared that allow generalized lithologic discrimination, identification of areas with high silica content, and the first reported detection of the carbonate secondary reststrahlen feature. Together with thermal‐inertia images, they permit identification of areas of subtle lithologic variation not shown on conventional geologic maps. Emissivity‐ratio spectra extracted from the data compare favorably with modeled laboratory spectra and establish for the first time the link among theory, measured physical properties, and color‐composited TIMS images. Identification of previously unknown silicification in the Tertiary volcanic rocks and mapping of a silicified structure and possible extensions in alluvium indicate that TIMS data can be a valuable tool for detecting subtle alteration associated with mineralization, particularly in less accessible or less well‐known areas.

Development of sedimentary basins in the Archean Abitibi belt, Canada: an overview

1992 ◽  
Vol 29 (10) ◽  
pp. 2249-2265 ◽  
Author(s):  
W. Mueller ◽  
J. A. Donaldson
Keyword(s):  
Shallow Water ◽  
Large Scale ◽  
Volcanic Rocks ◽  
Sedimentary Basins ◽  
Sedimentary Facies ◽  
Volcanic Zone ◽  
Sedimentary Cycles ◽  
Southern Volcanic Zone ◽  
Facies Associations ◽  
Sedimentary Cycle

Sedimentation in the Archean Abitibi greenstone belt occurred during four depositional episodes: (i) sedimentary cycle 1, 2730–2720 Ma; (ii) sedimentary cycle 2, 2715–2705 Ma; (iii) sedimentary cycle 3, 2700–2687 Ma; and (iv) sedimentary cycle 4, 2685–2675 Ma. Records of the first two sedimentary cycles are preserved in basins within the northern volcanic zone, whereas basins formed during the latter two sedimentary cycles are located within the southern volcanic zone of the Abitibi belt. Sedimentary cycles 1 and 3 represent deep-water facies, as indicated by turbidites, resedimented conglomerates, pelagic sediments, and ubiquitous iron-formations; subaerial deposits have not been identified. In contrast, sedimentary cycles 2 and 4 show a prevalence of fluvial to shallow-water marine and (or) lacustrine deposits. Tectono-magmatic influence on sedimentation during cycles 2 and 4 is documented by (i) the presence of numerous unconformities underlain by plutonic and volcanic rocks; (ii) locally voluminous shoshonitic and calc-alkaline volcanic rocks; (iii) abundance of plutonic detritus; (iv) rapid vertical and lateral facies changes; and (v) repetition of successions of large-scale (50–250 m thick) alluvial and shallow-water deposits. Sedimentary cycle 1 represents incipient arc basins dominated by volcaniclastic debris, whereas cycle 2 reflects unroofing of arc volcanoes down to the plutonic roots. The sedimentary basins of cycle 3 have been tentatively interpreted as basins connecting arc terranes, within which small extensional cycle 4 basins of the successor or pull-apart type developed. The sedimentary facies associations, the tectono-magmatic influence on sedimentation, the chronological basin evolution, and overall southward younging of the basins invite comparison with modern island arcs formed by plate-tectonic processes.

Where is the Iapetus suture in northern New England? A study of the Ammonoosuc Volcanics, Bronson Hill terrane, New Hampshire1This article is one of a series of papers published in this CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology.

2012 ◽  
Vol 49 (1) ◽  
pp. 189-205 ◽  
Author(s):  
Michael J. Dorais ◽  
Miles Atkinson ◽  
Jon Kim ◽  
David P. West ◽  
Gregory A. Kirby
Keyword(s):  
New England ◽  
Subduction Zone ◽  
Volcanic Rocks ◽  
Middle Ordovician ◽  
Isotopic Signatures ◽  
Basement Rocks ◽  
Iapetus Ocean ◽  
Maritime Canada ◽  
Laurentian Margin ◽  
Back Arc

The ∼470 Ma Ammonoosuc Volcanics of the Bronson Hill terrane of New Hampshire have back-arc basin basalt compositions. Major and trace element compositions compare favorably to coeval volcanic rocks in the Miramichi Highlands of New Brunswick and the Munsangan and Casco Bay volcanics of Maine, back-arc basin basalts of known peri-Gondwanan origins. Additionally, the Ammonoosuc Volcanics have Nd and Pb isotopic compositions indicative of peri-Gondwanan provenance. Thus, the Ammonoosuc Volcanics correlate with Middle Ordovician, peri-Gondwanan, Tetagouche–Exploits back-arc rocks of eastern New England and Maritime Canada. This correlation indicates that the Red Indian Line, the principle Iapetus suture, lies along the western margin of the Bronson Hill terrane. However, the younger (∼450 Ma) Oliverian Plutonic Suite rocks that intruded the Ammonoosuc Volcanics, forming domes along the core of the Bronson Hill anticlinorium, have Laurentian isotopic signatures. This suggests that the Ammonoosuc Volcanics were thrust westwardly over the Laurentian margin, and that Laurentian basement rocks are present under the Bronson Hill terrane. A plausible explanation for these relationships is that an easterly dipping subduction zone formed the Ammonoosuc Volcanics in the Tetagoughe–Exploits oceanic tract, just east of the coeval Popelogan arc. With the closure of the Iapetus Ocean, this terrane was thrust over the Laurentian margin. Subsequent to obduction of the Ammonoosuc Volcanics, subduction polarity flipped to the west, with the Oliverian arc resulting from a westerly dipping subduction zone that formed under the Taconic Orogeny-modified Laurentian margin.

scholarly journals Rapid Single Image-Based DTM Estimation from ExoMars TGO CaSSIS Images Using Generative Adversarial U-Nets

2021 ◽  
Vol 13 (15) ◽  
pp. 2877
Author(s):  
Yu Tao ◽  
Siting Xiong ◽  
Susan J. Conway ◽  
Jan-Peter Muller ◽  
Anthony Guimpier ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
Imaging System ◽  
Landing Site ◽  
Parameter Tuning ◽  
Processing Parameters ◽  
Input Image ◽  
Large Area ◽  
Laser Altimeter ◽  
Imaging Science

The lack of adequate stereo coverage and where available, lengthy processing time, various artefacts, and unsatisfactory quality and complexity of automating the selection of the best set of processing parameters, have long been big barriers for large-area planetary 3D mapping. In this paper, we propose a deep learning-based solution, called MADNet (Multi-scale generative Adversarial u-net with Dense convolutional and up-projection blocks), that avoids or resolves all of the above issues. We demonstrate the wide applicability of this technique with the ExoMars Trace Gas Orbiter Colour and Stereo Surface Imaging System (CaSSIS) 4.6 m/pixel images on Mars. Only a single input image and a coarse global 3D reference are required, without knowing any camera models or imaging parameters, to produce high-quality and high-resolution full-strip Digital Terrain Models (DTMs) in a few seconds. In this paper, we discuss technical details of the MADNet system and provide detailed comparisons and assessments of the results. The resultant MADNet 8 m/pixel CaSSIS DTMs are qualitatively very similar to the 1 m/pixel HiRISE DTMs. The resultant MADNet CaSSIS DTMs display excellent agreement with nested Mars Reconnaissance Orbiter Context Camera (CTX), Mars Express’s High-Resolution Stereo Camera (HRSC), and Mars Orbiter Laser Altimeter (MOLA) DTMs at large-scale, and meanwhile, show fairly good correlation with the High-Resolution Imaging Science Experiment (HiRISE) DTMs for fine-scale details. In addition, we show how MADNet outperforms traditional photogrammetric methods, both on speed and quality, for other datasets like HRSC, CTX, and HiRISE, without any parameter tuning or re-training of the model. We demonstrate the results for Oxia Planum (the landing site of the European Space Agency’s Rosalind Franklin ExoMars rover 2023) and a couple of sites of high scientific interest.

scholarly journals Mudrock Microstructure: A Technique for Distinguishing between Deep-Water Fine-Grained Sediments

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 653
Author(s):  
Shereef Bankole ◽  
Dorrik Stow ◽  
Zeinab Smillie ◽  
Jim Buckman ◽  
Helen Lever
Keyword(s):  
Grain Size ◽  
Deep Water ◽  
Sedimentary Facies ◽  
X Ray Diffraction ◽  
Weak Current ◽  
Large Area ◽  
Fine Grained ◽  
Mean Size ◽  
The Mean ◽  
Water Facies

Distinguishing among deep-water sedimentary facies has been a difficult task. This is possibly due to the process continuum in deep water, in which sediments occur in complex associations. The lack of definite sedimentological features among the different facies between hemipelagites and contourites presented a great challenge. In this study, we present detailed mudrock characteristics of the three main deep-water facies based on sedimentological characteristics, laser diffraction granulometry, high-resolution, large area scanning electron microscopy (SEM), and the synchrotron X-ray diffraction technique. Our results show that the deep-water microstructure is mainly process controlled, and that the controlling factor on their grain size is much more complex than previously envisaged. Retarding current velocity, as well as the lower carrying capacity of the current, has an impact on the mean size and sorting for the contourite and turbidite facies, whereas hemipelagite grain size is impacted by the natural heterogeneity of the system caused by bioturbation. Based on the microfabric analysis, there is a disparate pattern observed among the sedimentary facies; turbidites are generally bedding parallel due to strong currents resulting in shear flow, contourites are random to semi-random as they are impacted by a weak current, while hemipelagites are random to oblique since they are impacted by bioturbation.

scholarly journals Efficient and large-area all vacuum-deposited perovskite light-emitting diodes via spatial confinement

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peipei Du ◽  
Jinghui Li ◽  
Liang Wang ◽  
Liang Sun ◽  
Xi Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Large Scale ◽  
High Efficiency ◽  
Light Emitting Diodes ◽  
Scale Production ◽  
Nonradiative Recombination ◽  
Large Area ◽  
Spatial Confinement ◽  
Light Emitting ◽  
Large Scale Production

AbstractWith rapid advances of perovskite light-emitting diodes (PeLEDs), the large-scale fabrication of patterned PeLEDs towards display panels is of increasing importance. However, most state-of-the-art PeLEDs are fabricated by solution-processed techniques, which are difficult to simultaneously achieve high-resolution pixels and large-scale production. To this end, we construct efficient CsPbBr3 PeLEDs employing a vacuum deposition technique, which has been demonstrated as the most successful route for commercial organic LED displays. By carefully controlling the strength of the spatial confinement in CsPbBr3 film, its radiative recombination is greatly enhanced while the nonradiative recombination is suppressed. As a result, the external quantum efficiency (EQE) of thermally evaporated PeLED reaches 8.0%, a record for vacuum processed PeLEDs. Benefitting from the excellent uniformity and scalability of the thermal evaporation, we demonstrate PeLED with a functional area up to 40.2 cm2 and a peak EQE of 7.1%, representing one of the most efficient large-area PeLEDs. We further achieve high-resolution patterned perovskite film with 100 μm pixels using fine metal masks, laying the foundation for potential display applications. We believe the strategy of confinement strength regulation in thermally evaporated perovskites provides an effective way to process high-efficiency and large-area PeLEDs towards commercial display panels.

Pattern Writing by Implantation in a Large-Scale PSII System With Planar Inductively Coupled Plasma Source

2000 ◽  
Vol 624 ◽  
Author(s):  
Lingling Wu ◽  
Hongjun Gao ◽  
Dennis M. Manos
Keyword(s):  
Inductively Coupled Plasma ◽  
Large Scale ◽  
Lateral Diffusion ◽  
Plasma Source ◽  
Direct Writing ◽  
Large Area ◽  
Depth Profiles ◽  
Geometric Patterns ◽  
Planar Coil ◽  
Rf Antenna

ABSTRACTA large-scale plasma source immersion ion implantation (PSII) system with planar coil RFI plasma source has been used to study an inkless, deposition-free, mask-based surface conversion patterning as an alternative to direct writing techniques on large-area substrates by implantation. The apparatus has a 0.61 m ID and 0.51 m tall chamber, with a base pressure in the 10−8 Torr range, making it one of the largest PSII presently available. The system uses a 0.43 m ID planar rf antenna to produce dense plasma capable of large-area, uniform materials treatment. Metallic and semiconductor samples have been implanted through masks to produce small geometric patterns of interest for device manufacturing. Si gratings were also implanted to study application to smaller features. Samples are characterized by AES, TEM and variable-angle spectroscopic ellipsometry. Composition depth profiles obtained by AES and VASE are compared. Measured lateral and depth profiles are compared to the mask features to assess lateral diffusion, pattern transfer fidelity, and wall-effects. The paper also presents the results of MAGIC calculations of the flux and angle of ion trajectories through the boundary layer predicting the magnitude of flux as a function of 3-D location on objects in the expanding sheath

CSMC

2021 ◽  
Vol 5 (4) ◽  
pp. 1-22
Author(s):  
Hai Wang ◽  
Baoshen Guo ◽  
Shuai Wang ◽  
Tian He ◽  
Desheng Zhang
Keyword(s):  
Large Scale ◽  
Mobile Network ◽  
Signal Propagation ◽  
Spectrum Management ◽  
External Information ◽  
Temporal Uncertainty ◽  
Large Area ◽  
Fine Grained ◽  
Map Construction ◽  
Spatio Temporal

The rise concern about mobile communication performance has driven the growing demand for the construction of mobile network signal maps which are widely utilized in network monitoring, spectrum management, and indoor/outdoor localization. Existing studies such as time-consuming and labor-intensive site surveys are difficult to maintain an update-to-date finegrained signal map within a large area. The mobile crowdsensing (MCS) paradigm is a promising approach for building signal maps because collecting large-scale MCS data is low-cost and with little extra-efforts. However, the dynamic environment and the mobility of the crowd cause spatio-temporal uncertainty and sparsity of MCS. In this work, we leverage MCS as an opportunity to conduct the city-wide mobile network signal map construction. We propose a fine-grained city-wide Cellular Signal Map Construction (CSMC) framework to address two challenges including (i) the problem of missing and unreliable MCS data; (ii) spatio-temporal uncertainty of signal propagation. In particular, CSMC captures spatio-temporal characteristics of signals from both inter- and intra- cellular base stations and conducts missing signal recovery with Bayesian tensor decomposition to build large-area fine-grained signal maps. Furthermore, CSMC develops a context-aware multi-view fusion network to make full use of external information and enhance signal map construction accuracy. To evaluate the performance of CSMC, we conduct extensive experiments and ablation studies on a large-scale dataset with over 200GB MCS signal records collected from Shanghai. Experimental results demonstrate that our model outperforms state-of-the-art baselines in the accuracy of signal estimation and user localization.

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