scholarly journals Application of the Euler deconvolution 2D and 3D at the Pari syncline, internal area of the Paraguay Belt, Mato Grosso, Brazil

2021 ◽  
Vol 21 (3) ◽  
pp. 75-84
Author(s):  
Sérgio Raffael Silva Iocca ◽  
Sérgio Junior da Silva Fachin
Keyword(s):  
Magnetic Susceptibility ◽  
River Basin ◽  
Structural Control ◽  
3D Model ◽  
Mineral Exploration ◽  
Magnetic Data ◽  
Euler Deconvolution ◽  
Mato Grosso ◽  
High Level ◽  
2D And 3D

Among the several techniques that allow the estimation of mean depths from airborne geophysical magnetic data, the Euler deconvolution became popular due to the high level of reliability in the generated data. With the use of this tool, it is possible to study structures remotely at different crustal levels that may or may not contain mineralization, consequently being able to determine potential targets for mineral exploration or to study better its relation with the structural background. With the analysis of the magnetic susceptibility of subsurface and the inversion profiles of the magnetic data (Euler deconvolution 2D) were interpolate a 3D model of the region, that allowed to generate a descriptive suggestion of the geometry of the Pari syncline, located in the Cuiabá Group, in the northwestern portion of the Paraguay belt. It has a strong structural control in the context of the Pari River basin and a great auriferous potential, as evidenced by updated research and exploration data. The data applied in this paper were extract from the Cuiabá aerogeophysical project and previous mappings and have their mean depths correlated with the Cuiabá group.

Joint gravity and magnetic inversion in 3D using Monte Carlo methods

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. G153-G156 ◽  
Author(s):  
Miguel Bosch ◽  
Ronny Meza ◽  
Rosa Jiménez ◽  
Alfredo Hönig
Keyword(s):  
Monte Carlo ◽  
Magnetic Susceptibility ◽  
Prior Information ◽  
3D Model ◽  
Mass Density ◽  
Magnetic Data ◽  
Gravity And Magnetic ◽  
Magnetic Inversion ◽  
Gravity And Magnetic Data ◽  
Model Layer

We jointly invert gravity and magnetic data following a Monte Carlo method that provides estimation for a 3D model of the structure and physical properties of the medium. In particular, the model layer geometry and the density and magnetic susceptibility fields within layers are estimated, and their uncertainties are described with posterior probabilities. This method combines the gravity and magnetic data with prior information of the mass density and magnetic susceptibility statistics, and statistical constraints on the model interface positions. The resulting model realizations jointly comply with the observations and the prior statistical information.

scholarly journals Determination of Location and Depth of Mineral Rocks at Olode Village in Ibadan, Oyo State, Nigeria, Using Geophysical Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Akintayo O. Ojo ◽  
Toyin O. Omotoso ◽  
Olorunyomi J. Adekanle
Keyword(s):  
Magnetic Susceptibility ◽  
Geophysical Methods ◽  
Magnetic Data ◽  
Eastern Region ◽  
Contour Maps ◽  
Data Points ◽  
Resistivity Meter ◽  
2D And 3D ◽  
High Magnetic Susceptibility

Magnetic and resistivity geophysical methods were used to investigate the location and depth of mineral rocks at Olode village, Oyo State, Nigeria. 80 magnetic data points were acquired in 10 profiles using G-816 proton precession magnetometer with 10 m spacing in between each profiles and 10 m stations interval. After correcting diurnal variations, the raw magnetic data obtained were plotted as 2D and 3D magnetic contour maps. The residual anomalies obtained were plotted against distance using Microsoft Excel, and Peter’s half-slope method was used to find the depth to the magnetic sources. The magnetic signature obtained show considerable varying amplitude from a minimum value of 155.3 nT at a depth of 6.37 m to a maximum value of 670.3 nT at a depth of 6.25 m. Resistivity data were obtained using Campus Tiger resistivity meter and 9 VESs were acquired using Schlumberger configuration. All VESs were 150 m long, 75 m on each side of the referenced points which were 10 m apart. VESs 1–4 and 7–9 are underlined with rocks of high conductivity and susceptibility values. VESs 5 and 6 show rocks with low conductivity and susceptibility values. The results of these geophysical methods show that there are rocks with high magnetic susceptibility and conductivity values from the centre towards the eastern region of the study area and low magnetic susceptibility and conductivity values at the western region. On the average, the depths of these rocks from the surface fall in the interval of 5.80 m to 6.72 m.

scholarly journals Drone-based magnetic and multispectral surveys to develop a 3D model for mineral exploration at Qullissat, Disko Island, Greenland

2021 ◽  
Author(s):  
Robert Jackisch ◽  
Björn Henning Heincke ◽  
Robert Zimmermann ◽  
Erik Vest Sørensen ◽  
Markku Pirttijärvi ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
High Resolution ◽  
3D Model ◽  
Mineral Exploration ◽  
Magnetization Vector ◽  
Magnetic Anomalies ◽  
Magnetic Data ◽  
Constant Thickness ◽  
Magmatic Body ◽  
Wide Range

Abstract. Mineral exploration in the West Greenland flood basalt province is attractive because of its resemblance to the magmatic sulphide-rich deposit in the Russian Norilsk region, but it is challenged by rugged topography and partly poor exposure for relevant geologic formations. On northern Disko Island, previous exploration efforts have identified rare native iron occurrences and a high potential for Ni-Cu-Co-PGE-Au mineralization. However, Quaternary landslide activity has obliterated rock exposure at many places at lower elevations. To augment prospecting field work under these challenging conditions, we acquire high-resolution magnetic and optical remote sensing data using drones in the Qullissat area. From the data, we generate a detailed 3D model of a mineralized basalt unit, belonging to the Asuk Member (Mb) of the Palaeocene Vaigat formation. A wide range of legacy data and newly acquired geo- and petrophysical, as well as geochemical-mineralogical measurements form the basis of an integrated geological interpretation of the unoccupied aerial system (UAS) surveys. In this context, magnetic data aims to define the location and the shape of the buried magmatic body, and to estimate if its magnetic properties are indicative for mineralization. High-resolution UAS-based multispectral orthomosaics are used to identify surficial iron staining, which serve as a proxy for outcropping sulphide mineralization. In addition, high-resolution UAS-based digital surface models are created for geomorphological characterisation of the landscape to accurately reveal landslide features. UAS-based magnetic data suggests that the targeted magmatic unit is characterized by a pattern of distinct positive and negative magnetic anomalies. We apply a 3D magnetization vector inversion model (MVI) on the UAS-based magnetic data to estimate the magnetic properties and shape of the magmatic body. By means of using constraints in the inversion, (1) optical UAS-based data and legacy drill cores are used to assign significant magnetic properties to areas that are associated with the mineralized Asuk Mb, and (2) the Earth’s magnetic and the paleomagnetic field directions are used to evaluate the general magnetization direction in the magmatic units. Our results indicate that the geometry of the mineralized target can be estimated as a horizontal sheet of constant thickness, and that the magnetization of the unit has a strong remanent component formed during a period of Earth’s magnetic field reversal. The magnetization values obtained in the MVI are in a similar range as the measured ones from a drillcore intersecting the targeted unit. Both the magnetics and topography confirm that parts of the target unit were displaced by landslides. We identified several fully detached and presumably rotated blocks in the obtained model. The model highlights magnetic anomalies that correspond to zones of mineralization and is used to identify outcrops for sampling. Our study demonstrates the potential and efficiency of using multi-sensor high-resolution UAS data to constrain the geometry of partially exposed geological units and assist exploration targeting in difficult, poorly exposed terrain.

Folding-Controlled Assembly of Ortho-Phenylene-Based Macrocycles

2020 ◽  
Author(s):  
Viraj kirinda ◽  
Scott Hartley
Keyword(s):  
Self Assembly ◽  
Structural Control ◽  
Structural Changes ◽  
Condensation Product ◽  
Gel Permeation Chromatography ◽  
Emergent Behavior ◽  
Order Structure ◽  
High Level ◽  
Alkoxy Groups ◽  
Energy Surfaces

The self-assembly of foldamers into macrocycles is a simple approach to non-biological higher-order structure. Previous work on the co-assembly of ortho-phenylene foldamers with rod-shaped linkers has shown that folding and self-assembly affect each other; that is, the combination leads to new emergent behavior, such as access to otherwise unfavorable folding states. To this point this relationship has been passive. Here, we demonstrate control of self-assembly by manipulating the foldamers’ conformational energy surfaces. A series of o-phenylene decamers and octamers have been assembled into macrocycles using imine condensation. Product distributions were analyzed by gel-permeation chromatography and molecular geometries extracted from a combination of NMR spectroscopy and computational chemistry. The assembly of o-phenylene decamers functionalized with alkoxy groups or hydrogens gives both [2+2] and [3+3] macrocycles. The mixture results from a subtle balance of entropic and enthalpic effects in these systems: the smaller [2+2] macrocycles are entropically favored but require the oligomer to misfold, whereas a perfectly folded decamer fits well within the larger [3+3] macrocycle that is entropically disfavored. Changing the substituents to fluoro groups, however, shifts assembly quantitatively to the [3+3] macrocycle products, even though the structural changes are well-removed from the functional groups directly participating in bond formation. The electron-withdrawing groups favor folding in these systems by strengthening arene–arene stacking interactions, increasing the enthalpic penalty to misfolding. The architectural changes are substantial even though the chemical perturbation is small: analogous o-phenylene octamers do not fit within macrocycles when perfectly folded, and quantitatively misfold to give small macrocycles regardless of substitution. Taken together, these results represent both a high level of structural control in structurally complex foldamer systems and the demonstration of large-amplitude structural changes as a consequence of a small structural effects.

An Augmented Iteratively Re-weighted and Refined Least Squares Method for lp Minimization Problem in Inverse Modeling of Potential Field Magnetic Data

2020 ◽  
Vol 1 (3) ◽  
Author(s):  
Maysam Abedi
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Least Squares ◽  
Minimization Problem ◽  
Potential Field ◽  
Field Data ◽  
Least Squares Method ◽  
Porphyry Copper ◽  
Magnetic Data ◽  
Magnetic Field Data

The presented work examines application of an Augmented Iteratively Re-weighted and Refined Least Squares method (AIRRLS) to construct a 3D magnetic susceptibility property from potential field magnetic anomalies. This algorithm replaces an lp minimization problem by a sequence of weighted linear systems in which the retrieved magnetic susceptibility model is successively converged to an optimum solution, while the regularization parameter is the stopping iteration numbers. To avoid the natural tendency of causative magnetic sources to concentrate at shallow depth, a prior depth weighting function is incorporated in the original formulation of the objective function. The speed of lp minimization problem is increased by inserting a pre-conditioner conjugate gradient method (PCCG) to solve the central system of equation in cases of large scale magnetic field data. It is assumed that there is no remanent magnetization since this study focuses on inversion of a geological structure with low magnetic susceptibility property. The method is applied on a multi-source noise-corrupted synthetic magnetic field data to demonstrate its suitability for 3D inversion, and then is applied to a real data pertaining to a geologically plausible porphyry copper unit.  The real case study located in  Semnan province of  Iran  consists  of  an arc-shaped  porphyry  andesite  covered  by  sedimentary  units  which  may  have  potential  of  mineral  occurrences, especially  porphyry copper. It is demonstrated that such structure extends down at depth, and consequently exploratory drilling is highly recommended for acquiring more pieces of information about its potential for ore-bearing mineralization.

scholarly journals Spatial Analysis of the Drivers, Characteristics, and Effects of Forest Fragmentation

2021 ◽  
Vol 13 (6) ◽  
pp. 3246
Author(s):  
Zoe Slattery ◽  
Richard Fenner
Keyword(s):  
Forest Fragmentation ◽  
Forest Fires ◽  
Geographical Information ◽  
Agricultural Expansion ◽  
Forest Patches ◽  
Mato Grosso ◽  
Remote Imaging ◽  
Landscape Characteristics ◽  
High Level

Building on the existing literature, this study examines whether specific drivers of forest fragmentation cause particular fragmentation characteristics, and how these characteristics can be linked to their effects on forest-dwelling species. This research uses Landsat remote imaging to examine the changing patterns of forests. It focuses on areas which have undergone a high level of a specific fragmentation driver, in particular either agricultural expansion or commodity-driven deforestation. Seven municipalities in the states of Rondônia and Mato Grosso in Brazil are selected as case study areas, as these states experienced a high level of commodity-driven deforestation and agricultural expansion respectively. Land cover maps of each municipality are created using the Geographical Information System software ArcGIS Spatial Analyst extension. The resulting categorical maps are input into Fragstats fragmentation software to calculate quantifiable fragmentation metrics for each municipality. To determine the effects that these characteristics are likely to cause, this study uses a literature review to determine how species traits affect their responses to forest fragmentation. Results indicate that, in areas that underwent agricultural expansion, the remaining forest patches became more complex in shape with longer edges and lost a large amount of core area. This negatively affects species which are either highly dispersive or specialist to core forest habitat. In areas that underwent commodity-driven deforestation, it was more likely that forest patches would become less aggregated and create disjunct core areas. This negatively affects smaller, sedentary animals which do not naturally travel long distances. This study is significant in that it links individual fragmentation drivers to their landscape characteristics, and in turn uses these to predict effects on species with particular traits. This information will prove useful for forest managers, particularly in the case study municipalities examined in this study, in deciding which species require further protection measures. The methodology could be applied to other drivers of forest fragmentation such as forest fires.

ESTIMATION OF SOURCE PARAMETERS IN IBADAN, SOUTH – WESTERN NIGERIA USING DIGITIZED AEROMAGNETIC DATA

2018 ◽  
Vol 14 (2) ◽  
pp. 15-28
Author(s):  
A A ALABI ◽  
O OLOWOFELA
Keyword(s):  
Magnetic Susceptibility ◽  
Source Parameters ◽  
Granite Gneiss ◽  
Geological Structure ◽  
Magnetic Data ◽  
Susceptibility Map ◽  
Rock Types ◽  
Upward Continuation ◽  
Magnetic Basement ◽  
Local Wavenumber

Airborne magnetic data covering geographical latitudes of 7000‟N to 7030‟N and longitudes of 3 30′E to 4 00′E within Ibadan area were obtained from Nigeria Geology Survey Agency. The data were ana-lyzed to map the sub surface structure and the source parameters were deduced from the quantitative and qualitative interpretation of magnetic data. The upward continuation technique was used to de-emphasize short – wavelength anomaly while the depth to magnetic sources in the area was deter-mined using local wavenumber technique, the analytic signal was also employed to obtain the depths of the magnetic basement. Analysis involving the local wavenumber, upward continuation and appar-ent magnetic susceptibility techniques significantly improves the interpretation of magnetic data in terms of delineating the geological structure, source parameter and magnetic susceptibility within Iba-dan area.. These depth ranges from 0.607km to 2.48km. The apparent susceptibility map at the cut-off wavelength of 50 m ranges from -0.00012 to 0.00079 which agree with the susceptibility value of some rock types; granite gneiss, migmatite biotite gneiss, biotite muscovite granite, hornblende granite, quartz and schists. The result of the local wavenumber suggests variation along the profiles in the surface of magnetic basement across the study area.

Classifying Copper-Molybdenum-Gold Porphyry Deposit Alteration using Magnetic and Spectral data

2021 ◽  
Author(s):  
Oliver Dixon ◽  
William McCarthy ◽  
Nasser Madani ◽  
Michael Petronis ◽  
Steve McRobbie ◽  
...  
Keyword(s):  
Machine Learning ◽  
Magnetic Susceptibility ◽  
Spectral Data ◽  
Learning Algorithm ◽  
Copper Production ◽  
Magnetic Data ◽  
Machine Learning Algorithm ◽  
Porphyry Deposit ◽  
Remanent Magnetisation ◽  
Magnetic Remanence

<p>Copper is one of the most important critical metal resources needed to achieve carbon neutrality with a projected increase in demand of >300% over the next half century from electronics and renewables.  Porphyry deposits account for most of the global copper production, but the discovery of new reserves is ever more challenging. Machine learning presents an opportunity to cross reference new and traditionally under-utilised data sets with a view to developing quantitative predictive models of hydrothermal alteration zones to guide new, ambitious exploration programs.</p><p>The aim of this study is to demonstrate a new alteration classification scheme driven by quantitative magnetic and spectral data to feed a machine learning algorithm. The benefits of an alteration model based on quantitative data rather than subjective observations by geologists, are that there is no bias in the data collected, the arising model is quantifiable and therefore easy to model and the process be fully automated. Ultimately, this approach aids more detailed exploration and mine modelling, in turn, reducing the extraction process carbon footprint and more effectively identifying new deposits.</p><p>Presented here are magnetic susceptibility and shortwave infrared (SWIR) data collected from the KazMinerals plc. owned Aktogay Cu-Mo giant porphyry deposit, eastern Kazakhstan, which has a throughput of 30Mtpa of ore. These data are cross referenced using a newly developed machine learning algorithm. Generated autonomously, our results reveal twelve statistically and geologically significant clusters that define a new alteration classification for porphyry style mineralisation. Results are entirely non-subjective, reproducible, quantitative and modellable.</p><p>Importantly, magnetic susceptibility measurements improve the algorithm’s ability to identify clusters by between 29-36%; enhancing the sophistication of the included magnetic data promises to yield substantially better statistical results. Magnetic remanence data are therefore being complied on representative samples from each of the twelve identified clusters, including hysteresis, isothermal remanent magnetisation (IRM) acquisition, FORC measurements, natural remanent magnetisation (NRM) and anhysteretic remanent magnetisation (ARM). Through collaboration with industry partners, we aim to develop an automated means of collecting these magnetic remanence data to accompany the machine learning algorithm.</p>

scholarly journals Subterranean biodiversity in the Serra da Bodoquena karst area, Paraguay river basin, Mato Grosso do Sul, Southwestern Brazil

2014 ◽  
Vol 14 (3) ◽  
Author(s):  
Lívia Medeiros Cordeiro ◽  
Rodrigo Borghezan ◽  
Eleonora Trajano
Keyword(s):  
River Basin ◽  
Sustainable Use ◽  
Karst Area ◽  
Karst Aquifers ◽  
Effective Protection ◽  
Mato Grosso ◽  
Base Level ◽  
Paraguay River ◽  
Mato Grosso Do Sul ◽  
Subterranean Species

We present herein a synthesis of faunistic data from caves in the Serra da Bodoquena karst area, middle Paraguay River basin, Mato Grosso do Sul State. Those include phreatic, submerged and dry caves. Emphasis is given to troglobites (exclusively subterranean species), potentially threatened due to their morphological, physiological and behavioral specializations, associated to generally small distributions. The Bodoquena karst area distinguishes as a spot of high diversity of troglobites, such as trichomycterid and heptapterid catfishes, aquatic planarians and gastropods, arachnids (Eusarcus opilionids, ctenid spiders), Polydesmida diplopods, several collembolans, some insects, and Peracarida crustaceans, which include interesting phylogenetic relicts as spelaeogriphaceans. Four geographic compartments corresponding to microbasins, seemingly with biogeographic importance for the subterranean fauna, are recognized. Phreatobic troglobites (Trichomycterus catfishes, aquatic peracarids, planarians) distribute widely across these compartments and some well beyond (the spelaeogriphacean Potiicoara brasiliensis reaches Mato Grosso state), while those living in base-level streams (Rhamdia and Ancistrus catfishes) and the terrestrial ones, that live in the vadose (aerated zone) are generally restricted to one compartment. Many subterranean ecosystems in Mato Grosso do Sul are endangered by several threats described here and urgent actions for effective protection are required to guarantee a sustainable use of the land and the karst aquifers.

Magnetic concentration and polymorphism in di-n-octyl-, di-n-decyl-, and di-n-dodecylphosphinates of copper(II)

1985 ◽  
Vol 63 (5) ◽  
pp. 1111-1117 ◽  
Author(s):  
John S. Haynes ◽  
Katherine W. Oliver ◽  
Robert C. Thompson
Keyword(s):  
Differential Scanning Calorimetry ◽  
Magnetic Susceptibility ◽  
Heisenberg Model ◽  
Variable Temperature ◽  
Electronic Spectroscopy ◽  
Chain Structure ◽  
Magnetic Data ◽  
Scanning Calorimetry ◽  
Extended Chain ◽  
Linear Chains

Phosphinates of copper(II) of the type Cu(R2PO2)2 where R is n-octyl, n-decyl, and n-dodecyl have been synthesized and characterized by differential scanning calorimetry, vibrational and electronic spectroscopy, and variable temperature (300 to 4.2 K) magnetic susceptibility studies. Each of these compounds was obtained in distinct α and β structural forms. All materials appear to have the double phosphinate bridged extended chain structure and the magnetic data have been successfully analyzed according to the isotropic Heisenberg model for linear chains. The α forms exhibit antiferromagnetic behaviour with J values of −25, −29, and −29 cm−1 for the octyl, decyl, and dodecyl derivatives respectively. The β forms are ferromagnetic and have corresponding J values of 1.8, 2.1, and 2.3 cm−1 respectively. Magneto-structural correlations in these extended chain coordination polymers are discussed.

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