USE OF GEOCHEMICAL TOOLS FOR UNDERSTANDING GEOCHEMICAL AND GEOCHRONOLOGICAL DATA.A DISSERTATION SUBMITTED TO THE UTKAL UNIVERSITY INPARTIAL FULFILLMENT FOR THE DEGREE OFMASTER OF PHILOSOPHYINGEOLOGYByPINALI MOHAPATRARoll No: 25813VS17006Under the supervision ofDr.
D.S. PattanaikAssociate ProfessorP.G. DEPARTMENT OF GEOLOGYUTKAL UNIVERSITY, VANIVIHARBHUBANESWAR-751004, ODISHA20184622800-5292700Dr. Durga Shankar PattanaikP.G. Department of GeologyUtkal University, VaniviharBhubaneswar-751004Odisha CERTIFICATEThis is to certify that the dissertation work entitled “USE OF GEOCHEMICAL TOOLS FOR UNDERSTANDING GEOCHEMICAL AND GEOCHRONOLOGICAL DATA” is the result of genuine research work carried out by Ms.
Pinali Mohapatra, MPhil student of Department under my guidance and supervision. No part of this work has been submitted for any other degree or published in any other form.Place: Bhubaneswar Dr.
Durga Shankar PattanaikDate: ACKNOWLEDGEMENT I feel great pleasure to express my profound gratitude and supreme credit to my revered guide Dr. Durga Shankar Pattnaik for his constant guidance and supervision. His sincerity personal interest, constant encouragement, constructive criticism, and his acquaintance, with other eminent person in his field, have been of immense help for me to complete this thesis.I express my heartfelt gratitude to the Head of department Dr.
Bijay Kumar Ratha, for his kind suggestion, cooperation and granting permission to use the department laboratories. I am also grateful to my honorable teachers for their support and suggestion in carrying out my work. I thank to all the non-teaching staffs of the departments for their help and cooperation. I am also thankful to all my friends for moral support and help for preparing the thesis.
I can never forget the contribution of my parents who really boosted up my confidence and stood up the occasion. They deserve all the credit not only for this dissertation but also for all the good things I do in my life.Last but not the least, a bow down to the almighty God for being infinite source of energy, who always blesses me in every walk of life.Pinali Mohapatra DECLARATIONI do here by declared that the thesis entitled “USE OF GEOCHEMICAL TOOLS FOR UNDERSTANDING GEOCHEMICAL AND GEOCHRONOLOGICAL DATA” admitted to the P. G. Department of Geology Utkal University in partial fulfilment of degree of master of philosophy in Geology, is an original piece of work done by me and has not submitted either in whole or in part for the award of any degree or diploma.
Place: Bhubaneswar Pinali MohapatraDate:Dr. Bijay Kumar Ratha H.O.D of Geology Utkal University, Vanivihar Bhubaneswar-751004OdishaCERTIFICATEThis is to certify that the dissertation work entitled “USE OF GEOCHEMICAL TOOLS FOR UNDERSTANDING GEOCHEMICAL AND GEOCHRONOLOGICAL DATA” is submitted by Ms. Payaswini Das for the award of MPhil degree in Geology during 2016-2017, in her original work which has been carried out by her at Geology department, Utkal University, Vanivihar, Bhubaneswar, Odisha. Place: Bhubaneswar Dr. Bijay Kumar RathaDate: CONTENTS DeclarationCertificateAcknowledgementList of Tables and FiguresCHAPTER NO.
PAGE NO. CHAPTER-1 INTRODUCTION…………………………………………………………… 1 – 5CHAPTER-2INSTRUMENTATION………………………………………………………
2.1 XRF ………………………………………………………………..
2.2 Q-ICPMS………………………………………………………….2.3 LA-ICPMS…………………………………………………………CHAPTER-3………………………………………………………………….
.SAMPLE PREPARATION………………………………………….3.
1 COLLECTION OF GEOLOGICAL AND HYDROLOGICAL DATA……3.2 FIELD SAMPLING…………………………………………………………3.3 LABORATORY ANALYSIS………………………………………………CHAPTER-4…………………………………………………………………….
INTERPRETATION……………………………………………………00CHAPTER-1INTRODUCTION00CHAPTER-1INTRODUCTIONCHAPTER-1INTRODUCTIONGeochemistry may be defined as a science that deals with chemistry of the earth as a whole and its component parts. It utilizes the principles of chemistry to explain the mechanisms regulating the workings – past and present – of the major geological systems such as the Earth’s mantle, its crust, its oceans, and its atmosphere. It is more board and more restricted compared to geology. The term “Geochemistry” was first used by the German-Swiss chemist Christian Friedrich Schönbein, discoverer of ozone, in 1838. It has made important contributions to our understanding of many terrestrial and planetary processes, such as mantle convection, the formation of planets, the origin of granite and basalt, sedimentation, changes in the Earth’s oceans and climates, and the origin of mineral deposit.Elemental Behaviour The geochemical character of an element is largely governed by the electronic configuration of its atoms and hence is closely related to its systematic position in the periodic table (Mason, 1982). Goldschmidt (1937) classified elements into four broad categories:Lithophile Elements – elements have an affinity in silicate phase so are generally concentrated in the rock-forming minerals of the crust and mantle. Those elements that readily form ions with an outermost 8-electron shell.
eg Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba, B, Al, Sc, Y, REE, C, Si, Ti, Zr, Hf, Th, P, V, Nb, Ta, O, Cr, W, U, Fe, Mn, Pb, Ni, Co etc.Chalcophile Elements – elements form an intermediate sulphide phase. Those elements whose ions have 18 electrons in the outer shells; eg. Transition Elements.Siderophile Elements – elements have an af?nity for iron and therefore concentrate in the Earth’s core. Those elements whose outermost shell of electrons are for the most part incompletely filled, like Pt, Ir, Os, Ru, Rh, Pd, Au, Fe.
Atmophile Elements – These elements are extremely volatile and are concentrated in atmosphere and hydrosphere like O, N, H, and the inert gases.MAJOR ELEMENTS:Major elements may be defined as an element which is present in a rock in concentrations more than 1 wt% and are which dominate in any rock analysis. They include Si, Ti, Al, Cr, Mn, Mg, Fe, K, Ca, Na, P and their concentration is expressed as weight percent (wt.%) of the oxide.
Major element analysis is done only for cations assuming that they are accompanied by an appropriate amount of oxygen. Thus the sum of major element oxide will total to 100%. The volatiles such as water (H2O), CO2 and S are usually analyzed with major elements.
As they are present in such high concentrations, control the mineralogy and crystallization/melting behavior in igneous systems. They also control such properties as viscosity, density, diffusivity, etc. of magmas and rocks.The application of major element chemistry to rock classification and nomenclature is widely used in igneous petrology, in construction of variation diagrams, the plotting of the chemical composition of an igneous rock onto a phase diagramTRACE ELEMENTS:Trace element may be defined as an element which is present in a rock in concentrations less than 0.1wt.
%, i.e., less than 1000 parts per million. It is also defined as “an element whose activity obeys Henry’s Law in the system of interest”.
Trace elements are too dilute to form a separate phase, so they act strictly as substitutes for major or minor elements. It has become a vital part for petrological studies as these are most capable of discriminating between various petrological processes in comparison to major elements. They are most applicable to the processes controlled by crystal-melt or crystal-fluid equilibria. Trace elements are classified on the basis of their geochemical behavior.In the periodic table the trace elements are grouped into Rare Earth Elements or the Lanthanides (57-71), Platinum Group of Elements (PGE), Noble Metals (if Gold is also included in PGE) and the Transition Elements (21-30).
Trace Element Behaviour in Magmatic Systems: When the melting of the mantle takes place, the trace elements show a preference either towards the melt phase or the solid (mineral) phase. So elements which prefer the mineral phase are termed as Compatible Elements and elements which prefer the melt phase are termed incompatible, i.e. they are incompatible in the mineral structure and will leave at the first available opportunity. The degree of compatibility and incompatibility of trace elements will vary in their behavior in melts of different composition.
If the trace elements were to be divided on the basis of their charge / size ratio (which is also termed as Field Strength or electrostatic charge per unit surface area of the cation), then the elements can be grouped as HFSE (High Field Strength Elements) and LFSE (Low Field Strength Elements) or better known as LILE (Large Ion Lithophile Elements). HFSE are small highly charged cations and LILE are large cations of small charge. So elements with smaller radius and a relatively low charge tend to be compatible. These include a number of major elements and transition elements. HFS includes all the REEs, Sc, Y, Th, U, Pb, Zr, Hf, Ti, Nb and Ta. LILE includes Cs, Rb, Ba, K and to an extent Sr, divalent Eu and divalent Pb.
Partition Coefficient: The distribution of trace elements between phases may be described by Distribution Coefficient or Partition Coefficient (McIntire, 1963). The Nernest Distribution Coefficient is used extensively of a trace element between a mineral and a melt.It is defined by: Kd=Celement imineralCelement imeltWhere, Kd is the Nernst Distribution coefficientC is the concentration of element ‘i’ in ppm or wt%.Bulk Partition Coefficient: is a partition coefficient calculated for a rock for a specific element from the Nernst Partition Coefficients of the constituent minerals and weighted according to their proportions. It is defined by the expression – Di = x1 Kd1 + x2 Kd2 + x3 Kd3 + ……….
Where, Di is the bulk partition coefficient for element ‘i’X1 and Kd1 are the %age proportion of mineral 1 in the rock and the Nernst partition coefficient for element ‘i’ in mineral 1 respectively.The behaviour of trace elements during evolution of magmas may be considered in terms of their partitioning between crystalline and liquid phases, expressed as the partition coefficient, D. So elements that have D;1 are termed incompatible and are preferentially concentrated in the liquid phases during melting and crystallization. The elements which are incompatible with respect to normal mantle minerals (Olivine, Pyroxene, Spinel and Garnet) are the LILEs. In contrast, those with D;1 (Eg; Ni, Cr) are termed compatible, and these are preferentially retained in the residual solids during partial melting and extracted during crystallizing solids in fractional crystallization.
The preference of an element for a given phase is measured by its partition coefficient (D). It is customary to use trace elements whose partition coefficients are sensitive to the presence or absence of particular phases. For example the REEs exhibit partitioning behavior between garnet and melt and can therefore be useful in determining whether melt generation took place in the presence of that mineral, which in turn has implications for the depth of melting. MODELS FOR SOLID-MELT PROCESSES:Batch Melting:In this model, the melt remains in equilibrium with the solid, until at some point, perhaps when it reaches some critical amount, it is released and moves upward as an independent system.
Shaw (1970) derived the following equation to model batch melting:CilCio= 1Dio1-F+FWhere; Cio= the concentration of the trace element in the original assemblage before melting began, F is the weight fraction of melt produced – melt / (melt + rock).When Di = 1, there is no fractionation, and the concentration of the trace element is the same in both the liquid and the source. The concentration of a trace element in the liquid varies more as Di deviates progressively from 1.As F approaches 1, the concentration of every trace element in the liquid must be identical to that in the source rock, because it is essentially all melted.CilCio=1 as F?1On the other hand, as F approaches zero,CilCio= 1Dio as F?0Thus, if we know the concentration of a trace element in a magma (CL) derived by a small degree of batch melting, and we know Di we can estimate the concentration of that element in the source region (C0). The closer to unity the value of Dt the larger the range of F .For very incompatible elements, as Di approaches zero: CilCio= 1F as Dio?0This implies that if we know the concentration of a very incompatible element in both a magma and the source rock, we can determine the fraction of partial melt produced. This is the way in which trace elements can be used to evaluate melting processes at depth.
Rayieigh Fractionation Fractional melting occurs when the melt is constantly extracted from the residue during the ascent of magma through the earth’s mantle; that is the partial melt is continuously removed from the system as soon as it is formed, so that no reaction with the crystalline residue is possible. For this type of partial melting the bulk composition of the system is continuously changing. The concentration of some element in the residual liquid , CL, isCLCO=F1Di-1 Rayleigh crystal fractionationCLCO=1Di1-F21Di-1 Rayleigh fractional meltingWhere;CO= concentration of element in the original magmaF1= fraction of melt remaining after removal of crystalsF2= fraction of melt producedRare Earth ElementsREEs, a group of fourteen elements (Lanthanum to Lutetium) are members of Group III in the periodic table and have very similar chemical and physical properties.
Despite this similarity, these elements can be partially fractionated, one from the other, by several petrological and mineralogical processes. The wide variety of types and sizes of the cation co-ordination polyhedra in rock forming minerals provides means for chemical fractionation. It is this phenomenon which has important consequence in geochemistry.
The significant growth of interest in the geochemistry of REEs has come about because of the realization that the observed degree of REE fractionation in a rock or mineral can be a pointer to its genesis, and also because accurate quantitative analysis for the REE, both as a group and individually, is now possible on routine basis even when the elements occur at very low concentration. The application of REE abundances to petrogenetic problems has centered on the evolution of igneous rocks where such processes like partial melting of crustal or mantle materials, fractional crystallization, and/or mixing of magmas are involved. In these studies, the matching of observed REE abundances with those provided by theoretical modeling of petrogenetic processes has helped considerably to restrict the number of possible hypotheses on the genesis of a rock or mineral suite. The REEs have been divided into two sub-groups: those from La to Sm (i.e. lower atomic numbers and masses) being referred to as light rare earth elements (LREEs) and those from Gd to Lu (higher atomic numbers and masses) are referred to as heavy rare earth elements (HREEs).
Very occasionally, the term middle rare earth elements (MREEs) is loosely applied to the elements from Pm to Ho.In order to graphically compare the REE for different rocks, it is necessary to eliminate the Oddo-Harkins effect, which is the occurrence of higher concentrations for the elements with even atomic numbers as compared to the concentrations for the elements with odd atomic numbers. Thus, concentrations for the individual REE are generally normalized to their abundance in chondrites by dividing the concentration of a given element in the rock by the concentration of the same element in chondritic meteorites. Chondrites have been used because they are primitive solar materials which have been considered the parental material of the Earth (Hanson, 1980). The advantages of this method are that the abundance variation between the REE of odd and even atomic numbers is eliminated and the extent of any fractionation amongst the various REE in the specimen is discernible because there is considered to have been no fractionation between the light and heavy REE in chondrites.5 Mineral Melts Kd’s for REEA given mineral will have a characteristic effect on the REE pattern for a melt which allows identification of the influence of that mineral during melting or fractional crystallization; although it may not be possible to calculate the fraction of that mineral in the residue.
For most igneous minerals the mineral melt Kd’s in general increase with decreasing temperature and compositional variation from basic intermediate acidic. In this section individual minerals are considered with respect to how they qualitatively affect the concentration of the REE and the shape of the REE pattern in the melts/ the magnitude of the effect of a mineral is directly related to both the relative abundance of the mineral and the magnitude of the Kd’s. Some typical mineral melt Kd’s for the REEs are as follows (Hanson, 1980) : Feldspar – the feldspars have low Kd’s for the REE and large positive Eu anomalies. The plagioclase/melt Kd’s for the REE other than Eu are not strongly dependent on temperature or composition (Drake and Weill, 1975). The plagioclase Eu anomaly decreases with increasing fO2 and increasing temperature, but will be significant in almost all known terrestrial igneous systems (Drake 1975). Feldspar has but a minor effect on the REE pattern of the melt, except the large positive Eu anomaly in the Kd pattern will contribute to a negative Eu anomaly in the melt.Garnet – Garnet has very low Kd’s for the light REE and increasingly larger Kd’s for the HREE; the Kd’s decrease by an order of magnitude from rhyolitic to basaltic systems. The presence of Garnet leads to depletion of the HREE and generally contributes to a positive Eu anomaly in the melt.
Hornblende – the Kd’s for Hornblende show a strong dependence on composition and may be greater than 10 for the MREE in the rhyolitic systems. The presence of Hornblende will lead to a depletion of the MREE, less so the HREE and contribute to a positive Eu anomaly.Biotite – Biotite generally has low Kd’s for the REE and its presence should have little effect on the REE pattern of the melt.Perovskite – Perovskite has larger Kd’s for the LREE and MREE than the HREE.
The presence of significant Perovskite can lead to depletion or less enrichment of the LREE and MREE relative to the HREE (Irving, 1978). Zircon – Zircon has very large Kd’s (of the order of 100’s) for the HREE. However, its low abundance (generally less than 0.1%) leads to a minor depletion of the HREE in the melt.Apatite and Sphene – Apatite and Sphene have similar Kd patterns for the REE with Kd’s greater than one for all of the REE. Their generally low abundance reduces the effect of their large Kd’s. Both Apatite and Sphene lead to enrichment of the LREE and HREE relative to the MREE. The presence of Apatite could contribute to a positive Eu anomaly.
Mineral melt Kd’s for REE from dacites and Rhyolites from Hanson (1978). These are average values from Arth and Hanson (1975) which was selected from Nagasawa and Schnetzler (1971), Higuchi and Nagasawa (1969), Nagasawa (1970) and Schnetzler and Philpotts (1970). The data for anorthoclase are from Sun and Hanson (1976)right7620CHAPTER-2INSTRUMENTATION00CHAPTER-2INSTRUMENTATIONCHAPTER-2INSTRUMENTATIONX-Ray Fluorescence (XRF) SpectrometryXRF is an analytical method to determine the chemical composition of different kinds of materials. The materials can be solid, liquid, powdered, filtered or other form. In XRF, X-ray produced by the source irradiate the sample. The elements present in the sample will emit fluorescent X-ray radiation with discrete energies.
Different energy has different color, by measuring the energies of radiation emitted by the sample it is possible to determine which element are present, this is called qualitative analysis. Quantitative analysis is to determine how much of each element is present in the sample by measuring the intensities of emitted energies.An x-ray is a high-frequency electromagnetic radiation of energy intermediate between the far ultraviolet and gamma ray regions of the spectrum. The wavelengths of X-rays are in range from 0.01 to 10nm, which corresponds to energies in the range from 0.
125 to 125keV. The wavelength of X-ray is inversely proportional to its energy;E=h?=hc?Where,h is the Planck constant = 6.626 x10-34joules s-1,c is the velocity of light in vacuum = 2.998 x108 ms-1v is the frequency of the waveform (cycles per second)? is the wavelength expressed in Angstrom units (1A = 10-10 m) E is energy in keV (1keV = 1.602 x10-8 joule)The concept of spectrometers is a source, a sample and a detector. The source irradiates a sample and a detector measures the radiation coming from the sample.
The concentration range goe from ppm levels to 100%.Spectrometer systems are divided into two groups: Energy dispersive systems (EDXRF) and Wavelength dispersive systems (WDXRF) EDXRF spectrometers have a detector that is able to measure the different energies of the characteristic radiation coming directly from the sample. The detector can separate the radiation from sample into the radiation from the elements in the sample, this is called dispersion.WDXRF spectrometers use an analyzing crystal to disperse the different energies. All radiation coming from the sample falls on the crystal and the crystal diffracts the different energies in different directions like a prism. By placing the detector at certain angle, the intensity of X-rays with a certain wavelength can be measured.
Comparison of EDXRF and WDXRF SpectrometersXRF method is fast, accurate and non-destructive, and usually requires only a minimum of sample preparation. The precision and reproducibility of XRF analysis is very high. The elements with high atomic numbers have better detection limits than the lighter elements. Applications are broad and include mining, mineralogy and geology, environmental analysis of water and waste materials along with metal, cement, oil, polymer, plastic and food industries.
Q-ICPMSLA-ICPMSInductively Coupled Plasma Mass Spectrometry (ICP-MS):Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is an analytical technique used for elemental determinations. The technique was commercially introduced in 1983. ICP-MS are composed of three primary components:An inductively coupled plasma ion source, where ions are produced, accelerated, and focused;An analyzer, where the ions are focused and filtered to produce a beam where the ions have the same approximate energy and can be separated based on their mass/charge ratios;Collector, where the ion beams are measured.Quadrupole Mass Spectrometer;The quadrupole mass spectrometer is a very compact mass dispersion device which was developed from ideas formulated in the 1950s by Paul et.al (1958). This instrument consists of four rod which are aligned with high degree of accuracy. Each pair of opposite rods is electrically connected to a positive dc voltage being applied to one pair and an equal negative dc voltage to the other pair.
The quadrupole mass filter is commonly used with inductively coupled argon plasma or gas chromatogram sources. Ions introduced into the instrument are accelerated through a relatively low potential gradient and caused to drift along the axis of the quadrupole.LA-ICPMSLA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is a powerful analytical technology that enables highly sensitive elemental and isotopic analysis to be performed directly on solid samples.
LA-ICP-MS begins with a laser beam focused on the sample surface to generate fine particles – a process known as Laser Ablation. The ablated particles are then transported to the secondary excitation source of the ICP-MS instrument for digestion and ionization of the sampled mass. The excited ions in the plasma torch are subsequently introduced to a mass spectrometer detector for both elemental and isotopic analysis.
right0CHAPTER-3SAMPLE PREPARATION00CHAPTER-3SAMPLE PREPARATIONCHAPTER-3METHODOLOGY2447925153670SAMPLESAMPLE2266950107952857500358140287655033909049053757874028479758826500828675116840819150107315809624107315000326390Archival Sample00Archival Sample4086225316865Thin Section00Thin Section2124075297815CRUSHING00CRUSHING287655028575028956002857502085975187960Tema mill powdering00Tema mill powdering342900028067022574252616203124200255905Powder (500 mesh)00Powder (500 mesh)990600255905Powder (250 mesh)((25000Powder (250 mesh)((250437006926098500216217540259011334754152907620039624076200405765157162526289066040396240133350405765right107950Wilfley Gravity separator 00Wilfley Gravity separator 1828800165100LOI 00LOI 790575155575XRF 00XRF -352425155575Digestion 00Digestion 8382027305494347510160-390525495935ICP-MS 00ICP-MS 4257675229235Drying 00Drying 36385502546354943475111760162877545085Magnetic minerals00Magnetic minerals3648075385445right42545Isodynamic separator00Isodynamic separator2628900382905163830047625Non-magnetic minerals00Non-magnetic minerals1657350218440Bromoform separation separationfff00Bromoform separation separationfff26384251206501666876434975Di-iodomethane separation00Di-iodomethane separation26955753270251647825612776Binocular microscopeHand-picked samples00Binocular microscopeHand-picked samplesSAMPLE PROCESSINGThe rock samples that are collected can be either analyzed petrographically or geochemically. The samples are crushed and grinded according to the type of analysis to be conducted. For the geochronological studies and study of major and trace elements the samples are powdered and for petrological studies thin sections are prepared. Methods followed are;Hydraulic crusher- in this the bigger fraction of samples are crushed into smaller fragments (~4-5cm). Some pieces of samples are kept for preparing thin section and other are further processed.
Jaw crusher- the crushed samples are further crushed for smaller fragment of desirable size (1cm). It consists of a vibrating feeder, movable and immovable jaw which are made up of chrome steel. Tema-Mill- the crushed samples are powdered to desirable size. For XRF analysis the powder should be of ?300 mesh and for geochronological studies it should be of ?500 mesh.
It consists of concentric rings made up of tungsten carbide. The rings collide among them to powder the samples. Tema-mill is time consuming and percentage of contamination is very less. Before adding samples it should be cleaned with acetone to avoid contamination.Sample preparation for XRF analysis-XRF is used for determination of major and trace element chemistry of rock samples.Pellet preparation: Pressed pellets are prepared using 40 mm aluminum cups filled with Boric acid crystals as binder.
Finely powdered sample (-300 mesh) is sprinkled over boric acid and pressed in a 40 ton hydraulic press to produce a circular 40 mm disk. The pressed powder pellets allows trace element determinations, with limits of detection up to 1 ppm for selected elements. The elements determined presently are K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Ce, Pb, Th. Light elements like Si, Al, Mg and Na are less precise by this method. All major and trace elements are determined on sample pellets for which fused glass disk cannot be made (for e.g. river and marine sediments, soils etc.).
Fused glass disk is prepared on a Claisse Fluxy instrument. One gram of finely powdered sample is mixed with 5 gram of flux (LiT/LiM/LiBR 49.75/49.75/0.50, Pure) and fused in a platinum crucible. The fluxer is microprocessor controlled and uses LPG and in controlled manner raises the temperature up to 1000°C. It has built in programmes for different sample types. Rotating and stirring of crucible for uniform mixing and pouring the fused liquid on to a platinum mold to produce 30 mm glass disk is done automatically.
It is also possible to create need based programmes with different gas flow, crucible tilt, mixing speed and length of each step.Fused disks are excellent for analyzing major elements as it reduces matrix effects; eliminates particle size effects; and provides a homogeneous specimen. Samples which contain higher than normal concentrations of elements like lead, tin, arsenic and/or antimony (as they can seriously damage the platinum ware) and samples which contain organic matter are not suitable for this method of sample preparation.
Elements determined by this method are Na, Mg, Al, Si, P, K, Ca, Ti, Mn, and Fe.For GeochronologySieve analysis- sieving in done by water gravity process. In case of rock samples the powder of ~500mesh is sieved and for sedimentsWilfley gravity separation: it is a shaking table in which gravity separation is done on the basis of densities of mineral. It separates high specific gravity minerals from low specific gravity mineral.The table consist of a rectangular shape deck with riffles, a feeder through which samples are added. The table shakes in forward and backward direction.
The slope of the table is adjusted in such a way that the heavy minerals will concentrate at one end due to the shaking movement. A thin film of water is allowed to flow through table, so that the lighter minerals can move and the heavy minerals can concentrate. The samples are collected in three forms, the light fraction, the mixed and the heavy fraction. The samples are then dried in the oven.Frantz Magnetic separation-Magnetic separation depends on the magnetic susceptibility of the minerals to be separated. It simply follows the principle of electromagnetism i.e.
; when current is passed through the coil, magnetic field is created which in turn increases the strength of the magnet in the coil. As a result of which the magnetic and nonmagnetic sediments are separated which is collected in two different boxes. The separator can be rotated in both directions of slope i.e. forward slope and sideward slope.
The separation depends on (1) the tilt of the chute, (2) the amperage applied to electromagnet and, (3) the slope and rate of feed to the chute. At the lower end of the chute the particles are separated into two boxes, one consisting of grains of higher susceptibility (Magnetic) and the other consisting of grains of lower susceptibility (non-magnetic).The dried samples are taken for separation.
Hand magnet is used to separate strongly magnetic minerals like magnetite and pyrrhotite. Heavy liquid separationBromoform separation- Bromoform (CHBr?) with specific gravity=2.89 g/cc. Bromoform liquid is mostly used to separate the heavy minerals having specific gravity ;2.89g/cc.Di-iodomethane separation- Diiodomethane (CH?I?) with specific gravity=3.32 g/cc. the minerals having specific gravity more than 3.
32g/cc are separated.The separation of heavy mineral using heavy liquid is on the basis of their different densities. The non-magnetic minerals collected from the magnetic separator are used for separation.
The separation in carried out inside a lamellar fume hood. The samples are separated in using a separating funnel, the samples are added into the funnel and heavy liquid was poured to it. The mixture was properly stirred using glass rod and was kept undisturbed for sometimes, so that the heavy minerals get settled properly.
The heavy minerals get settled at the bottom and the light minerals use to float at the top. The heavy minerals are collected and kept for drying.right18415CHAPTER-4SOFTWARES FOR PLOTTING00CHAPTER-4SOFTWARES FOR PLOTTINGCHAPTER-4SOFTWARES FOR PLOTTINGGRAPHERGrapher is a computer program that is able to create 2D and 3D graphs from simple and complex equations. It includes a variety of samples. It is also capable of dealing with functions and compositions of them.
One can edit the appearance of graphs by changing line colors, adding patterns to rendered surfaces, adding comments, and changing fonts and styles used to display them. Grapher is able to create animations of graphs by changing constants or rotating them in space.Grapher is a fully featured graphing calculator, capable of creating both 2D graphs including classic (linear-linear), polar coordinates, linear-logarithmic, log-log, and polar log as well as 3D graphs including standard system, cylindrical system, and spherical system. It also supports multiple equations in one graph and comes with several pre-made equation examples.It is one of the few sophisticated graphing programs available capable of easily exporting clean vector art for use in printed documents (although exporting 3D graphs to vector is not possible). Animation of graphs is also supported in both 2D and 3D, generating a QuickTime file.
Further, it is also possible to use the operating system’s copy and paste feature to copy equations from the application’s visual equation editor. By doing so, Grapher functions as something of an equation editor, as the user may copy images, EPS, PDF or LaTeX versions of entered equations into other applications. Any equation can be entered and copied, not just plottable equations.
CORAL DRAWCorelDraw is a vector graphics editor developed and marketed by Corel Corporation. It is also the name of Corel’s Graphics Suite, which bundles CorelDraw with bitmap-image editor Corel Photo-Paint as well as other graphics-related programs. CorelDraw is designed to edit two-dimensional images such as logos and posters.The software is a robust graphics suite, providing many features for users to edit graphics. These features include contrast adjustment, color balancing, adding special effects like borders to images, and it is capable of working with multiple layers and multiple pages. It is used by professional artists, educators, students, businesses and the general public.SURFERSurfer is a contouring and 3D surface mapping software program that runs under Microsoft Windows. The Surfer software quickly and easily converts your data into outstanding contour, surface, wireframe, vector, image, shaded relief, and post maps.
Virtually all aspects of your maps can be customized to produce exactly the presentation you want using Surfer software tools. Producing publication quality maps has never been quicker or easier. Surfer is used extensively for terrain modeling, landscape visualization, surface analysis, contour mapping, 3D surface mapping, gridding, and volumetrics.DIDGERDidger is use for comprehensive digitizing, georeferencing, reprojection, tiling, and mosaicking features transform paper maps, graphs, photographs, and well logs into dynamic digital formats. Didger is a must-have tool for anyone working with inconsistent data formats. Didger offers both manual and automatic digitizing tools.It improves the accuracy of your project and quickly transforms unreferenced data files, vector data, or imagery into real-world coordinates for use in real-world projects.
Didger offers 10 spatial transformation methods and automatically calculates the root-mean-square (RMS) error value to verify accuracy. Alternatively, shift features in any direction with mathematical operations. Didger automatically warps images to eliminate distortion. It transforms data into dynamic formats, regardless of coordinate system. Didger gives you immediate access to imagery from any online web mapping services (WMS), public or private.0-635CHAPTER-5INTERPRETATION00CHAPTER-5INTERPRETATIONCHAPTER-5INTERPRETATIONHARKERQAPTASSAb-An-OrData reduction for traceHarker for traceREE Chrodritic normalizedPrimitive mantle normalized
