Probabilistic Cover-Basement Interface Characterization in Cloncurry, Australia, using Magnetotelluric Soundings

2020 ◽  
Author(s):  
Hoël Seillé ◽  
Gerhard Visser ◽  
Jelena Markov ◽  
Janelle Simpson
Keyword(s):  
3D Model ◽  
Metallogenic Province ◽  
Mount Isa ◽  
Electrical Conductivities ◽  
Iocg Deposit ◽  
Local Geology ◽  
Reliability And Robustness ◽  
Cover Thickness ◽  
Survey Planning ◽  
Mineral System

<p>Cloncurry is located in the Mount Isa province in Queensland, NE Australia. The Mount Isa Province is a well-known metallogenic province in Australia which hosts many IOCG deposits. One of them is the Ernest Henry IOCG deposit, which was found below cover in the 90’s. The cover in this area comprises of regolith and the Jurassic-Cretaceous sediments of Eromanga and Carpentaria Basins. This deposit appears to belong to a complex mineral system which extend over the entire Cloncurry District.</p><p>A magnetotelluric (MT) survey was conducted in 2016 by Geoscience Australia and The Geological Survey of Queensland in the vicinity of the Ernest Henry IOCG deposit, in order to characterize the electrical properties of the mineral system beneath it. The derived 3D electrical conductivity model highlights the variable cover thickness over the area, and a correlation between conductors located in the upper crust and known mineral occurrences such as the Ernest Henry mine.</p><p>The use of 3D deterministic inversions of MT data is very powerful to image the electrical structure of the mineral system at the crustal scale but lacks resolution to image a realistic sharp cover-basement interface and precludes quantitative assessment of uncertainty around the results.</p><p>In this work we propose a workflow to image a geologically realistic cover-basement interface and bring insights on the reliability and robustness of different parts of the model using a probabilistic inversion approach.</p><p>We selected a subset of the MT survey and for each site we ran a probabilistic 1D trans-dimensional Markov chain Monte Carlo sampler for estimating subsurface conductivity and its associated uncertainty. These inversions are designed to be robust to non-1D effects present in the data. Next, we performed a petrophysical analysis using available down hole measurements to derive constraints on the electrical conductivities of the different lithologies found in the area. Then these petrophysical constraints, coupled to spatial lateral constraints, are used to fuse the 1D probabilistic ensembles into a 3D posterior ensemble.</p><p>The pseudo 3D model obtained is compared to a 3D model derived from a conventional 3D deterministic inversion using the same data to assess the value and validity of the workflow. Preliminary interpretation of the results is performed using petrophysical data and established local geology knowledge. Conclusions around the benefits of this workflow to give a different perspective on the characterization of a mineral system located under cover and to provide basis for future survey planning are presented.</p>

scholarly journals A Workflow to Define, Map and Name A Carbonatite- or Alkaline Igneous-Associated REE-HFSE Mineral System: A Case Study from SW Germany

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 97 ◽  
Author(s):  
Graham Banks ◽  
Benjamin Walter ◽  
Michael Marks ◽  
Pete Siegfried
Keyword(s):  
Raw Materials ◽  
The European Union ◽  
Metallogenic Province ◽  
System A ◽  
System Concept ◽  
Potential Trap ◽  
Critical Components ◽  
Definition Of ◽  
Targeting Effectiveness ◽  
Mineral System

Security of supply of “hi-tech” raw materials (including the rare earth elements (REE) and some high-field-strength elements (HFSEs)) is a concern for the European Union. Exploration and research projects mostly focus on deposit- to outcrop-scale description of carbonatite- and alkaline igneous-associated REE-HFSE mineralization. The REE-HFSE mineral system concept and approach are at a nascent stage, so developed further here. However, before applying the mineral system approach to a chosen REE-HFSE metallogenic province its mineral system extent first needs defining and mapping. This shifts a mineral system project’s foundation from the mineral system concept to a province’s mineral system extent. The mapped extent is required to investigate systematically the pathways and potential trap locations along which the REE-HFSE mass may be distributed. A workflow is presented to standardize the 4-D definition of a REE-HFSE mineral system at province-scale: (a) Identify and hierarchically organize a mineral system’s genetically related sub-divisions and deposits, (b) map its known and possible maximum extents, (c) name it, (d) discern its size (known mineral endowment), and (e) assess the favorability of the critical components to prioritize further investigations. The workflow is designed to generate process-based perspective and improve predictive targeting effectiveness along under-evaluated plays of any mineral system, for the future risking, comparing and ranking of REE-HFSE provinces and plays.

Reconciling Cover Thickness Estimates in Cloncurry Region in Queensland, Australia using Bayesian Estimate Fusion

2020 ◽  
Author(s):  
Jelena Markov ◽  
Gerhard Visser
Keyword(s):  
Mineral Exploration ◽  
Optimal Solution ◽  
Geophysical Data ◽  
Bayesian Estimate ◽  
Mount Isa ◽  
History Of ◽  
Cover Thickness ◽  
Inference Methods ◽  
Drill Holes ◽  
Fault Information

<p>The Cloncurry region lies in NW of Queensland and includes the Mount Isa Inlier, one of the most highly endowed metallogenic provinces in Australia, which has a long history of mining and exploration. The area is covered by the Jurassic-Cretaceous Carpentaria and Eromanga Basin sediments with the Mount Isa Inlier outcropping to the West and South. The fully concealed Millungera Basin underlies younger basins to the East. In order to de-risk further mineral exploration in this region it is important to know the thickness of cover. There are a variety of geophysical data available that can be used to estimate cover thickness. The point depth estimates of cover are derived from geophysical data using different inference methods. In order to create a map, these individual depth estimates must be reconciled/interpolated. The conventional interpolation methods do not produce the most optimal solution since these methods don’t easily account for discrepancies in the geophysical data distribution, resolution of the data and consequently variable accuracy of the cover thickness depth estimates. Also, most of these techniques do not produce an uncertainty estimate of the result. We have developed a Bayesian estimate fusion method that accounts for the variable data inaccuracies of the point cover thickness estimates which produces a map of cover thickness and its uncertainty. Additionally, the method uses non-intersecting drill holes, which were not usually utilised to create a map of the cover thickness. The method deals with outliers, by differentiating between the point depth estimates related to the cover-basement interface and the false positives that might be coming from the intrasedimentary units or the deeper basement. Lastly, the method incorporates existing fault information which allows to better capture sharp cover thickness changes.</p>

Electronic structure studies of conducting polymers by electron energy-loss spectroscopy

1996 ◽  
Vol 54 ◽  
pp. 160-161
Author(s):  
J. Fink
Keyword(s):  
Electronic Structure ◽  
Conducting Polymers ◽  
Conjugated Polymers ◽  
Electron Acceptors ◽  
Electron Donors ◽  
Light Emitting ◽  
One Dimensional ◽  
New Class ◽  
Electrical Conductivities ◽  
Electron Energy Loss

Conducting polymers comprises a new class of materials achieving electrical conductivities which rival those of the best metals. The parent compounds (conjugated polymers) are quasi-one-dimensional semiconductors. These polymers can be doped by electron acceptors or electron donors. The prototype of these materials is polyacetylene (PA). There are various other conjugated polymers such as polyparaphenylene, polyphenylenevinylene, polypoyrrole or polythiophene. The doped systems, i.e. the conducting polymers, have intersting potential technological applications such as replacement of conventional metals in electronic shielding and antistatic equipment, rechargable batteries, and flexible light emitting diodes.Although these systems have been investigated almost 20 years, the electronic structure of the doped metallic systems is not clear and even the reason for the gap in undoped semiconducting systems is under discussion.

Generation of a 3D model to better mimic NAFLD in vitro

2016 ◽  
Vol 54 (12) ◽  
pp. 1343-1404
Author(s):  
LS Spitzhorn ◽  
MA Kawala ◽  
J Adjaye
Keyword(s):  
3D Model

Evaluation of geometrical benchmark artifacts containing multiple overhang lengths fabricated using material extrusion technique

2020 ◽  
Vol 14 (3) ◽  
pp. 7296-7308
Author(s):  
Siti Nur Humaira Mazlan ◽  
Aini Zuhra Abdul Kadir ◽  
N. H. A. Ngadiman ◽  
M.R. Alkahari
Keyword(s):  
3D Model ◽  
Laser Scanner ◽  
Dimensional Accuracy ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Layer Technique ◽  
Subtractive Manufacturing ◽  
Manufacturing Features ◽  
Layer Problem

Fused deposition modelling (FDM) is a process of joining materials based on material entrusion technique to produce objects from 3D model using layer-by-layer technique as opposed to subtractive manufacturing. However, many challenges arise in the FDM-printed part such as warping, first layer problem and elephant food that was led to an error in dimensional accuracy of the printed parts especially for the overhanging parts. Hence, in order to investigate the manufacturability of the FDM printed part, various geometrical and manufacturing features were developed using the benchmarking artifacts. Therefore, in this study, new benchmarking artifacts containing multiple overhang lengths were proposed. After the benchmarking artifacts were developed, each of the features were inspected using 3D laser scanner to measure the dimensional accuracy and tolerances. Based on 3D scanned parts, 80% of the fabricated parts were fabricated within ±0.5 mm of dimensional accuracy as compared with the CAD data. In addition, the multiple overhang lengths were also successfully fabricated with a very significant of filament sagging observed.

Dynamics of CO2 emission from chernozems under agricultural use

2017 ◽  
Vol 4 (3) ◽  
pp. 43-49
Author(s):  
M. Miroshnychenko ◽  
O. Siabruk
Keyword(s):  
Carbon Dioxide ◽  
Agricultural Practices ◽  
Growing Season ◽  
Warm Period ◽  
Direct Seeding ◽  
Soil Tillage ◽  
Plant Residues ◽  
Hydrothermal Conditions ◽  
Organic Mineral ◽  
Mineral System

Aim. The comparison of the effect of hydrothermal conditions and various agricultural practices on the emission of CO 2 from chernozems in the Left-Bank Forest-Steppe of Ukraine. Methods. The dynamics of the intensity of carbon dioxide emissions from chernozem calcic (typical chernozem – in Ukrainian classifi cation) was studied during the growing season of 2011–2012. The observations were based on two fi eld experiments with various methods of soil till- age (6–7 years from the beginning of the experiment) and fertilization systems (21–22 years from the beginning of the experiment). Particularly, plowing at 20–22 cm, disking at 10–12 cm, cultivation at 6–8 cm and direct seeding using Great Plains drill were studied among the soil tillage methods. Mineral system (N 45 P 50 K 45 ), organic system (manure 8 t/ha) and combined organic-mineral system (manure 8 t/ha + N 45 P 50 K 45 ) were studied among fertilization systems. The intensity of CO 2 fl ux was determined using the non-stationary respiratory chambers by the alkaline absorption method, with averaging of the results during the day and the frequency of once a month. Results. During the warm period, the emission of carbon dioxide from the soil changes dynamically depending on temperature and humidity. The maximum of emission coincides with the periods of warm summer showers in June-July, the minimum values are characteristic for the late autumn period. The total emission losses of carbon in chernozems over the vegetation period ranged from 480 to 910 kg/ha and varied depending on the methods of tillage ± (4.0–6.0) % and fertilization systems ± (3.8–7.1) %. The changes in the intensity of CO 2 emission from the soil under different methods of soil tillage are associated with hydrothermal regime and the depth of crop residues location. The biggest difference is observed im- mediately after tillage, but in the spring period the differences are only 12–25 %, and after drying of the top layer of soil become even less. Direct seeding technology provides the greatest emission of CO 2 from chernozem, which is fa- cilitated by better water regime and more complete mineralization of plant residues on the soil surface. Annual losses of carbon are the least under disking of soil at 10–12 cm. The changes in the intensity of CO 2 emission from the soil under different fertilization systems are associated with the involvement of the additional organic matter from plant residues and manure to the microbiological decomposition. The greatest emission was observed under the organic- mineral fertilization system, which increased the loss of carbon by 7–8 % in comparison with the mineral system in the unfavorable hydrothermal year and by 11–15 % in the more favorable year. These differences are observed mainly during the fi rst half of the growing season when there is a clear tendency to increase the intensity of soil respiration. Conclusions. The hydrothermal conditions of the warm period of the year are decisive in the formation of the CO 2 emission fl ow from chernozems. Due to the improvement of agricultural practices, emissions might be reduced but not more that by 15 % of natural factor contribution.

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