Structural geometry of orogenic gold deposits： Implications for exploration of world-class and giant deposits

With very few exceptions, orogenic gold deposits formed in subduction-related tectonic settings in accretionary to collisional orogenic belts from Archean to Tertiary times. Their genesis, including metal and fluid source, fluid pathways, depositional mechanisms, and timing relative to regional structural and metamorphic events, continues to be controversial. However, there is now general agreement that these deposits formed from metamorphic fluids, either from metamorphism of intra-basinal rock sequences or de-volatilization of a subducted sediment wedge, during a change from a compressional to transpressional, less commonly transtensional, stress regime, prior to orogenic collapse. In the case of Archean and Paleoproterozoic deposits, the formation of orogenic gold deposits was one of the last events prior to cratonization. The late timing of orogenic gold deposits within the structural evolution of the host orogen implies that any earlier structures may be mineralized and that the current structural geometry of the gold deposits is equivalent to that at the time of their formation provided that there has been no significant post-gold orogenic overprint. Within the host volcano-sedimentary sequences at the province scale, world-class orogenic gold deposits are most commonly located in second-order structures adjacent to crustal scale faults and shear zones, representing the first-order ore-forming fluid pathways, and whose deep lithospheric connection is marked by lamprophyre intrusions which, however, have no direct genetic association with gold deposition. More specifically, the gold deposits are located adjacent to ～10°-25° district-scale jogs in these crustal-scale faults. These jogs are commonly the site of arrays of ～70° cross faults that accommodate the bending of the more rigid components, for example volcanic rocks and intrusive sills, of the host belts. Rotation of blocks between these accommodation faults causes failure of more competent units and/or reactivation and dilation of pre-existing structures, leading to deposit-scale focussing of ore-fluid and gold deposition.Anticlinal or antiformal fold hinges, particularly those of ＇locked-up＇ folds with ～30° apical angles and overturned back limbs, represent sites of brittle-ductile rock failure and provide one of the more robust parameters for location of orogenic gold deposits.In orogenic belts with abundant pre-gold granitic intrusions, particularly Precambrian granitegreenstone terranes, the boundaries between the rigid granitic bodies and more ductile greenstone sequences are commonly sites of heterogeneous stress and inhomogeneous strain. Thus, contacts between granitic intrusions and volcano-sedimentary sequences are common sites of ore-fluid infiltration and gold deposition. For orogenic gold deposits at deeper crustal levels, ore-forming fluids are commonly focused along strain gradients between more compressional zones where volcano-sedimentary sequences are thinned and relatively more extensional zones where they are thickened. World-class orogenic gold deposits are commonly located in the deformed volcano-sedimentary sequences in such strain gradients adjacent to triple-point junctions defined by the granitic intrusions, or along the zones of assembly of micro-blocks on a regional scale. These repetitive province to district-scale geometrical patterns of structures within the orogenic belts are clearly critical parameters in geology-based exploration targeting for orogenic gold deposits.

Recognition of two contrasting structural-and mineralogical-gold mineral systems in the Youjiang basin,China-Vietnam:Orogenic gold in the south and Carlin-type in the north

The gold deposits in the Youjiang basin,totaling>25 Moz gold,have traditionally been thought to be of Carlin-type,particularly those with extensional structural geometries in the northern basin dominated by platform sedimentary sequences.However,the structural geometries,mineralization styles and alteration types for the Jinya,Gaolong and Nakuang gold deposits in the south-central part of the basin are remarkably similar to those of unequivocal orogenic gold deposits.Structural studies show that gold mineralization in the three gold deposits was controlled by tight“locked-up”anticlines with NW−SE-to E−W-trending and/or concomitant thrusts and/or shear zones,which resulted from NE−SW-to N–S-trending compression or transpression following the Early Triassic closure of the Paleo-Tethyan Ocean.Alteration zones in these deposits are dominated by silicification(quartz),sericitization,sulfidation and carbonation.Zoned pyrites in these deposits comprise Au-poor cores and invisible Au-bearing rims with minor external free gold.Euhedral to subhedral auriferous arsenopyrites also contribute to the gold budget.These features indicate that the three gold deposits are sediment-hosted orogenic gold deposits that contrast markedly with the Carlin-type gold deposits in the northern part of the Youjiang basin in terms of structural geometry and timing,mineralization style and nature of associated alteration.Although additional reliable ages using robust methodologies are still required,the older isotopic ages of the gold deposits in the south-central Youjiang basin are also consistent with earlier formation during transpression that predated extension during orogenic collapse,the period of formation of the Carlin-type gold deposits in the northern Youjiang basin.

Geometries and electronic structures of Zr_(n)Cu(n=2–12) clusters: A joint machine-learning potential density functional theory investigation

Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.

The geometry structures and electronic properties of Li_mB_n(m+n=12) clusters

The geometric structures, electronic properties, total and binding energies, harmonic frequencies, the highest occupied molecular orbital to the lowest unoccupied molecular orbital energy gaps, and the vertical ionization potential energies of small LimBn （m＋ n = 12） clusters were investigated by the density functional theory B3LYP with a 6-31 I＋G （2d, 2p） basis set. All the calculations were performed using the Gaussian09 program. For the study of the LimBn clusters, the global minimum of the B 12 cluster was chosen as the starting point and the boron atoms were gradually replaced by Li atoms. The results showed that as the number of Li atoms increased, the stability of the LimBn cluster decreased and the physical and chemical properties became more active. In addition, on average there was a large charge transfer from the Li atoms to the B atoms.

Structural,Electronic and Optical Properties of the Monoclinic α-CoV_2O_6

First-principles calculations based on density functional theory are performed to investigate the structural,electronic and optical properties of monoclinic α-Co V2O6.Firstly,the geometry structures obtained by geometry optimization are consistent with the experimental values.Then,the energy band structure is studied using both GGA and GGA＋U methods.It is found that the on-site Coulomb repulsion of the Co 3d orbital plays a key role in describing the electronic properties of α-Co V2O6,and is necessary to open the energy band gap.According to the partial density of states（PDOS）,significant Co–O and V–O hybridizations are observed in the valence and conduction bands,respectively.Furthermore,the Co–O and V–O bonds are found to have significant covalent characters.Below the absorption threshold ~1.9 e V,no absorption can be detected.However,there exists a strong and wide absorption band in the energy range from 1.9 to 11 e V.Such novel optical properties imply that the α-Co V2O6 may have some potential optical applications.

About the Thermodynamics and Aging of Self-Organizing Systems

We know that the total daily energy dissipation increases in complex organisms like the humans. It’s very probable that this increase in total energy dissipation is related to the progressive increase in mass. But we also know that day by day the dissipation of energy per unit mass decreases in these organisms. We intend to verify if this decrease is only an expression of the second law of thermodynamics, or if it is related to the increase in mass that occurs in these organisms. For this, we set ourselves the following objectives: verify the correlation between total energy dissipation and the evolution of body mass, and verify the correlation between the dissipation of energy per unit of mass and the evolution of body mass. As a result of the data analysis, we found a high degree of correlation between total energy dissipation and the evolution of body mass. And we also found a high correlation between the energy dissipated per unit of mass and the evolution of body mass. We can conclude that self-organization produces not only an increase in mass, but also a decline in energy dissipation per unit mass beyond what is expected by the second law of thermodynamics.

A simple method for determining independent fracture toughness and tensile strength of rock

This paper develops a model that only requires two sets of small-size rock specimens with the ratio of the structural geometry parameter maximum to minimum ae,max:ae,min≥3:1 to determine the rock fracture and strength parameters without size effect and predict the actual structural performance of rock.Regardless of three-point-bending,four-point-bending,or a combination of the above two specimen types,fracture toughness KICand tensile strength ftof rock were determined using only two sets of specimens with ae,max:ae,min≥3:1.The values KICand ftwere consistent with those determined using multiple sets of specimens.The full structural failure curve constructed by two sets of small-size specimens with ae,max:ae,min≥3:1 can accurately predict large-size specimens fracture failure,and±10%upper and lower limits of the curve can encompass the test results of large-size specimens.The peak load prediction curve was constructed by two sets of specimens with ae,max:ae,min≥3:1,and±15%upper and lower limits of the peak load prediction curve can cover the small-size specimen tests data.The model and method proposed in this paper require only two sets of small-size specimens,and their selection is unaffected by the specimen type,geometry,and initial crack length.

Beyond Biological Aging: Table Analysis

Keeping in mind the relationship between the basal metabolic rate and the change in weight in the aging process, we propose to verify the holographic description of the same. For this we set ourselves the following objectives: Verify the correlation between total energy dissipation and energy dissipation per unit body mass, and verify the correlation between the total energy dissipation and the body mass. As a result of the data analysis, we obtained a coherent representation of our proposal. A high degree of correlation between the total energy dissipation in an organism and the basal metabolic rate/dry kg was found. Such a condition implies that the stated biological system satisfies the Holographic Principle.

OUT-OF-PLANE COMPRESSIVE PROPERTIES OF HEXAGONAL PAPER HONEYCOMBS

The compressive behaviour of paper honeycombs is studied by means of an experimental analysis. Experiment results show how geometry aspects of hexagonal paper honeycombs, e.g. the height of paper honeycomb, the thickness and length of honeycomb cell-wall, the drawing ratio of hexagonal honeycomb, affect the compressive properties of the paper honeycombs. It is in good agreement with the theory model. The constraint factor K of the critical buckling stress is mainly determined by the length of honeycomb cell-wail. It can be described as K=1.54 for B type paper honeycombs and K=3.32 for D type paper honeycombs. The plateau stress is the power exponent function of the thickness to length ratio of honeycomb cell-wall, and the experiment results show that the constant is 13.2 and the power exponent is 1.77. The research results can be used to characterize and improve efficiently the compressive properties of paper honeycombs.

VARIABLE STRUCTURE CONTROL OF AIRCRAFTFOR ATMOSPHERIC DISTURBANCE

Variable structure control (VSC) applied to atmospheric disturbance sup-pression is presented. The conditions are stipulated: the sliding mode existenee condi-tion, and invanance condition of atmospheric disturbanee in the variable structuresystem (VSS). A method of eigenstructure assignment technique for switching surfaeedesign is proposed. Based on different atmospheric disturbanee characteristics, such asrandom turbulence, discrete gust and wind shear, two kinds of control laws are derived that possess strong robustness. An example shows that this control approach isfeasible and effective.

Syntheses and Structures of Two Novel Salicylate-containing Mononuclear Manganese Complexes

Two salicylate containing mononuclear manganese complexes formulated as [Mnand characterized by elemental analysis, IR and single-crystal X-ray diffraction analyses. Crystal data for compound 1： monoclinic, space group C2/c, a=30.748（6）, b=8.1933（13）, c=21.137（4） A, β=126.772（4）°, V=4265.5（13）A^3, Z=8, Mr=471.34, Dc=1.468 g/cm^3, μ=0.667 mm^-1, F（000）=1952,the final R=0.0637, wR=0.1783 （I 〉 2σ（I）） and GOOF=1.073; and those for compound 2： monoclinic,space group C2/c, a=14.505（5）, b=11.048（4）, c=20.711 （7）（A）, β=103.603（6）°, V=3225.6 （18）A^3, Z=4, Mr=668.65, Dc=1.377 g/cm^3, μ=0.466 mm^-1, F（000）=1416, the final R=0.0373, wR=0.1125 （I 〉2σ（I））, and GOOF=1.000. The Mn atoms of both complexes are six-coordinated in an axially elongated octahedral geometry for 1 and an axially compressed octahedral geometry for 2, and their oxidation states have been determined to be trivalent by bond valence sum calculation.

EMC Improvement for High Voltage Pulse Transformers by Pareto-optimal Design of a Geometry Structure Based on Parasitic Analysis and EMI Propagation

High voltage pulse transformers have an essential role in pulsed power systems and power conversion applications.Improving the electromagnetic behavior of such devices leads to better efficiency and low-level electromagnetic interference(EMI)noise propagation in systems.In this paper,a high voltage pulsed power system is considered and analyzed to improve their electromagnetic compatibility(EMC).The new generation of pulsed power systems that use SiC and GaN fast switches in capacitor charger power electronic circuits,face far more EMI challenges.Moreover,in this paper,the EMI propagation paths in the pulsed power system are realized and analyzed.The EMI noise level of the system is obtained and compared to the IEC61800-3 standard.To improve the EMC,the parasitic parameters of the transformer,as the main path of EMI circulation,are optimized to block the EMI propagation in the pulsed power system.To achieve this result,the parasitics are modeled and calculated with a novel and accurate energy distribution model.Then,by defining a cost function,the geometry structure of the transformer is optimized to lower the parasitics in the system.Three pareto-optimal techniques are investigated for the cost function optimization.The models and results are verified by the 3D-finite element method(FEM)and experimental results for several given scenarios.FEM and experimental verifications of this model,make the model suitable for any desirable design in any pulsed power system.Finally,the EMI noise level of the system after optimization is shown and compared to the IEC61800-3 standard.

Geometry optimization and electronic structures of molecules H_3AXAH_3

The geometries of molecules H_3AXAH_3(X=O,S,Se and A=C,Si)have been optimized using STO-3G ab initio calculations and gradient method and the results are in good agreement with reported experimental values.From the STO-3G optimized geometries,we have also calculated the electronic structures of these molecules using 4-31G and 6-31G basis sets to obtain the MO energies. atomic net charges and dipole moments.The ionization potentials calculated by 6-31G basis set are in good agreement with experimental values.

Sensor selection for received signal strength-based source localization in wireless sensor networks

Generally, localization is a nonlinear problem, while linearization is used to simplify this problem. Reasonable approximations could be achieved when signal-to-noise ratio (SNR) is large enough. Energy is a critical resource in wireless sensor networks, and system lifetime needs to be prolonged through the use of energy efficient strategies during system operation. In this paper, a closed-form solution for received signal strength (RSS)-based source localization in wireless sensor network (WSN) is obtained. A sensor selection method is proposed to improve the localization accuracy as well as to save energy consumption. By selecting only a limited number of sensor nodes based on the model accuracy and geometry structure analysis, localization performance is improved, and energy consumption is reduced. In addition, extensive simulations are presented to demonstrate that the estimation performance with the proposed sensor selection method is better than that without sensor selection.