Airborne geophysic

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The airborne geophysics surveys, which they are performed by aircraft or helicopter,consist the variations measurement of the several earth physical parameters.

The most important of the measurable parameters such as conductivity which it equal to specific resistance reverse, the magnetic susceptibility, density and radioactive elements aggregation including potassium, and thorium and uranium, any change near the earth surface which it causes the measurable changes in these parameters show the practical applications of the air borne geophysics. The above parameters measurement devices are electromagnetic (FM), magnetic, gravity, gamma ray spectrometry (AGS), The EM surveys map the three- dimensional variations in conductivity which they have been caused due to change in lithology, alteration intensity and underground water volume or it’s salinity. The magnetic surveys are used for preparing the magnetic susceptibility alteration map which it often relates to rocks magnetite percent variation, and the gamma ray spectrometry surveys measure radiations made from one or more natural or man-made radio rays. The above methods are used for multiple aims. In some cases, one method put the direct sign from the desired are presence. For example, the situations which the magnetic method is used for finding Nickel and iron ores. In other cases, one method may provide only sign from being suitable of situation for the desired ore presence, for example, the magnetic method in oil exploration often is a means of detection in determining igneous beds rock depth, so that it is ensured the oil exploration with deposits thickness determination.

We can perform the geophysical surreys exploration in Land, sea and air. In areas which they are very large (more than hundred thousands km2) the airborne methods are often used. Because these methods are performed  with more precision and very more fast.

Air borne magnetic method

            The magnetic method is an oldest geophysical method which it is used for determining buried ores place and also for determining structures relating to oil and gas deposits. This method is a one which it’s origin is a natural and it is caused from earth magnetic field effects over rocks the earth magnetic field is an equivalent with one constant magnetic which it is in directional of north-south near land rotation axis. 99% land magnetic field has an internal origin which it accounts as main field and it changes a relatively slow, and the remaining 1% has external origin and it changes relatively fast.

The main field variations usually is very smaller than a main field, and it occurs from caused local magnetic anomalies near earth crust surface which it is a variations result in rocks magnetic ore content.

The review of these alterations constitute an exploratory geophysics aims, because we can interpret the local magnetic field anomalies relating to local earth structure. Of course u one of very important information sources in this field is rocks which it is possible that they have been magnetized at it’s formation constantly. Using rock magnetization measurement. We can deduce past history of the magnetic field.

In magnetic method, the obtained anomalies from field surveys are interpreted based on magnetic susceptibility alterations and/or constant magnetization. There are each two above figures at temperature below curie point in rocks, So the magnetic anomalies are only limited op to 30-40 km depths.

 

Air borne magnetic method applications

   to search ore or magnetic host rock:

Consisting iron reserves, ultramafic rocks having chrome, some massive sulfate (usually Nickel), kimberlitic having diamond and tin- tungsten or rare earths having granite.  

Geology maps preparation:

Consisting litho logy and structural maps in the weathered or covered area and the sediment basin geometry and also zone studies for the tectonic aims (For example crystal studies) and the suitable mineralization environments exploration.

  Depth determination (basement):

It is for the hydrocarbons and non-metal ores exploration and also ores exploration having buried basement, (Such as gold).

4-      If this method use from electromagnetic and induced polarization (IP) methods, it can be used in determining a metal and non-metal conductive, and interpreting the polarized or conductive masses geometry.

 Engineering studies, underground water, archeology and hazard zonation:

Consisting faults map and berried joints preparation, curie point isotherm depth determination and metal objects search.

   Airborne radiometry method:

Some elements isotopes are unstable and they are converted to more stable core with an active ion radiation diffusion. These isotopes are called radioactive isotopes or radioisotope. The main three type of ray is diffused from degrading the radioactive materials such as alpha, Beta and gamma rays, which alpha ray consists two protons and two neutron, as they have a charge and mass, they are attracted by few air combat particles transport a single negative charge and they can move up to 1 m in air. The annihilation of one alpha or beta usually remains a new core in excited state, and extra energy radiates as gamma rays.

These rays have not charge and mass , hence they we very penetrative, as they can penetrate up to 30 cm in rock and several hundred meter in air.

Each photon of gamma ray has a separate energy and this energy is a radiation source isotope characteristic. This method, forms a gamma ray spectrometry base (minty, 1997). The natural souces of gamma rays, which they are in air reviews, are potassion.Uranium and thorium. Therefore, radiometry method is based on the diffused gamma ray energy and current measurement during the decay of potassium, uranium and thorium radioactive isotopes and the relative approximation of these materials in surface rocks. The raw radiometry information, which they are recorded in 256 channel spectrum,

Consists 5 energy windows as follows

“Window” “EnergyRange” “ChannelRange”

Total count 410-2810 Key 35-240

Potassium 1370-1570 key 117 -134

Uranium 1660-1860 key 142-159

Thorium 2410-2810 key 206-240

Cosmic 3000-00 key 256

Because of the existing differences between radiations which are caused from potassium, thorium and uranium decay, Total radiations measurement in certain energy range is performed as a known channel. As with total gamma ray energy measurement, we will have total radiation parameter (Total count). The isometric method is used at cone exploration, but it depends on being appear the rocks order consideration, as the zone will be attracted by bed rocks radiation so lime covered deposits. The relative and absolute focus of the radioactive elements change con miserably with litho logy and the radiometry can reflect the adsorptive litho logy variations inside rather united rock units. On the other hand, kinds of very difference rocks can have a similar radiometry signs.

Falsie rocks, which they have outcropped, particularly granites and frolic volcanism have a clear radiometry.

A-      Expansion of surface soils and other surface processes:

Bed rock radiation may decline by materials which they put between rock and detector, because the radiometry reviews can record information up to 35cm depth. The soil moisture rise also declines radiations.

B-      The change in survey parameter, such as aircraft height which it transport a sensor above earth surface. (Terrain clearance), as in 150 m flight height, one 15m variation causes 10% change in the measurement amount .

-          Beaker structure features such as old worked mines and/or road and rail which it entails fresh rocks application, and as linear features is seen which it can intercept geology boarders.

          Potassium:

Potassium is a one of big earth crest compounds (%2,35) that it is alkali element, and it’s big hosts are pathetic feldspars (specially orthoclase and microcline with almost 13% potassium) and mica (biotitic, and muscovite with 8% potassium) . Potassium is rather high in falsie rocks (granite) and low in mafia basalts and very low in donates and peritonitis. During weathering the potassium site is destroyed in biotitic, pathetic feldspars and muscovite. The free potassium in weathering can be attracted by Ares having potassium such as iolite or other clay ores like Monte marinate in a suitable situation.

In gamma ray review, the potassium appears with mew 1/46 gamma ray measurement which it was caused from the decay k40. This isotope forms %2 from natural potassium and it is a correct measurement from existing potassium in earth. (Dickson&Scott, 1997).

The alteration patterns can be determined with me variations in radiometry signs often with increasing in potassium. Some of alkali and calico alkali porphyry (mot) gold and copper ore deposits accompany with prosaic hydrothermal alteration.

   

          Uranium:

Uranium is a small compound from earth crust (ppm3) which it can be seen as oxide ores and granitite and uranutorite silicate ores in rocks. The monastic, Centime and zircon are a main ores having uranium, which only zircon and monastic are stable during the eathering. The free uranium from ares during the weathering may remain antigen iron oxides and clay ores and form a uranium reserves in a suitable situation. Parent uranium is a decay series which it tends to stable state pb206. Uranium does not diffuse a gamma ray during it’s decay, and the most gamma ray diffuse by it’s daughter isotopes. The uranium rock detecting radiometry survey near surface is an important.

Thorium

Thorium is a small compound from earth crust (ppm12).

Thorium compounds solubility usually is low except in acid solutions. Bat organic compounds may increase thorium solubility in neutral pH.

Thorium may be seen in alienate, monazite, xenotime and zircon at levels up to 1000 ppm. The main ores having thorium(monazite and zircon) are a stable during the weathering, which they are likely aggregated in heavy ore rocks reserves.

The free thorium as the result of ores degradation during the weathering may remain in oxides and iron hydroxides or titanium with clays oils. Thorium does not also diffuse a gamma ray during the decay like uranium, and it is in the decay series which it tends to stable pb208. The most active gamma rays diffuse by daughter isotopes made from

TL 208. (Dickson & Scott, 1997). As during alteration process, the thorium is not commonly enriched, the ratio k/the is a good mark for the pathetic alteration. In tropical wee, the bed rock radio rays distribution changes considerably with extensive weathering, as the increase in thorium aggregation and the interaction decline in potassium is seen in the weathered area.

Air borne radiometry applications

 Radioactive host rock or ore rock search are as follows:

Uranium reserve, rocks having thorium or uranium such as rate earths, tin, tungsten or other ores, enriched rocks from potassium consisting economic kames (like kimberlitic), potassium altercated zones, which they likely accompany with porphyry gold or copper, and the enriched uranium indicating some gold or copper reserves.

 Geology maps preparationconsisting litho logy map in areas of the sedimentary soils, the exploration for the mineralization suitable environments and the tracing of the alluvial sources for the compatible with geochemistry.

 Hydro carbons exploration

Consisting radioactive halos exploration above hydro carbonated reserves.

          Airborne electromagnetic methods:

All electromagnetic induce systems are described based on two important physical acts as follows:

According to Biota- Sarver act, all electrical currents cause magnetic fields. The flowing electrical car rent in direct wire causes a magnetic field around electrical current axis.

Second act is a faraday act that according to it, the magnetic field, which it changes with time, induces one electrical current in each conductive. The airborne electromagnetic devices have one transmitter system and receiver system, which they build in a Bird that it hangs under helicopter. One variable magnetic field with time, which it is called primary field, and it is caused by alternative electrical waves in the transmitter coil, is sent to earth side. The electromagnetic waves penetrate inside earth and they are diffused inside subsurface rocks. The primary EM fields are dissipated from the transmitter coil to the receiver coil which this function performs through above earth surface and also underground. Should subsurface rocks are homogeneous and electrically insulation, there usually will not be any differences between the diffused fields above earth surface and/or inside earth. Only some field intensity is declined which it was diffused inside earth. But when there are bodies in subsurface. The field fluctuations caused from primary Eu field magnetic component will cause the eddy current induce inside conductive body. The induced current intensity depends on electrical conductivity.

Conductive body size and shape and also primary field frequency and intensity and the conductive body direction and position to the transmitter. The eddy currents cause a secondary magnetic field in conductive body. The secondary magnetic field induces electrical signals in the receiver coil

In fact, the receiver coil in EM system responds to the resulted field (Hr) which it is a vector sum of primary fields (Hp) and secondary fields (Hs).

Hr field differs with the primary field regarding phase and also domain. The difference between primary EM fields and Hr can determine the presence of one subsurface conductive body and provide an information about it’s geometry position and electrical features.

The electromagnetic method penetration depth is about several hundred meter, which it depends on geology cover and measurement system.

       Airborne electromagnetic method applications:

 Direct search of the metal conductive bodies (typical massive sulfide, pyrite conductive ores and/or partite or granite).

Consist: pytoclastic massive sulfide ore rocks of copper, lead, zinc and valuable metals which they usually accompany with pyrite and/or partite .

-          Copper-Lead host carbonates which they accompany with parasite, pyrite or partite and sometimes with graphite horizons.(For weak targets).

-          Massive partite- pentelandite masses consisting nicked and sometimes copper and valuable metals with mafia and ultramafic rocks (for good targets).

    Silver vein deposits often with stibnite, copper, cobalt, nickel, pyrite in sedimentary and volcanic rocks (commonly for weak targets).

-          Quartz vein having gold and pyrite, sometimes with stibnite, silver, bismuth in sedimentary and volcanic rocks and likely intrusive rocks(weak targets).

-          Scorn deposits of copper, zone , lead and valuable metals usually with pyrite and magnetite around igneous intrusive (For rather weak targets)

       Graphite zones having gold with pyrite or without it in sedimentary and tuffaceous beds (For rather good targets).

 

    Indirect search of ore reserves suitable hosts:

     kimberlitic having diamond

         serpent ionized mafia- ultramafic rocks of  nickel and asbestos host(and sometimes copper and valuable metal).

     Literate nicked reserves in conductive coprolite .

   Faults and shear of zones which they are a host of hydrothermal gold and uranium and etc.

 Geology maps preparation

The variation detection in litho logy (and structure) usually with magnetic and radiometry methods .

  Application in underground water, agricultural

         to prepare saline soils and water map

     to prepare environmental wastes and mineral acid waterways map

        to determine new water basins

The collected airborne geophysics information in Iran which it is used by geology organization as follows:

     regional information:

Bet ween1353&1356, two airborne magnetic surveys with high sensitive has been performed by Aero (Texas, service focus,) for geology organization, which in genera it covers the most part of Iran, the aim for doing is to obtain more information from Iran regional geology and tectonic and also to determine suitable zones for a detailed exploration of ores and hydrocarbons. The carried out survey in 1353-54 and 1355-56 consist 89058 and almost 162612 km contouring line with the line spacing S/7 km and tie line distance 40km respectively. The used aircraft is a two-motor air-conductor which it has transported one magnetometer cesium vapor with the record sensitive %2 GAMA. Iran total field intensity map has been prepared using these data according to figure No.2 in geology organization.

   Iran atomic energy airborne geophysics information:

The above information consists magnetic and radiometry (u,th,k)at local scale, that it has been surveyed by three foreign company, Astrid Australia, prakla-seismos Germany, and CGG France in area of Iran measuring 2000, 600 km for atomic energy organization in 1355-57.

The magnetic information has been surveyed by proton magnetometer with the sensitive 0/5 Nanotela and the IGRF correction has been performed on it by 1975 model, and the radiometry information has been surveyed by gamma ray spectrometry with following characteristics:

(PI ARAY 512 CHANNELS (FW)5.300 CM NAI(TL)

                                                       (RW) 5.300 CM NAI(TL)

(PI ARRAY 512 CHANNELS (FW)50.300 CM NAI(TL)

 (RW)33. 600 CM NAI(TL)

The performed flights figures are as follows

Line spacing : 500 meters

Nominal Terrain clearance: 120 meters

Sample interval: 1 second

Aircraft speed (FW) Max.70 meters/second

Aircraft speed (RW)Max.46 meters/second

   Iran copper national company regional information:

In 1371 , Aerobat performed one airborne geophysics survey consisting magnetic- radiometry and electromagnetic at Kerman zone in detail.

From these information was used for porphyry copper exploration and the related

epithermal reserves.

  

The airborne geophysics survey characteristics are as follows

Line spacing 200m, Tie line distance 10m, east north- west south flight directive, the surveyed zone area 7000 km2 , and consisting 36000 km linear and 380 flight from march to Oct.1992 The reviewed zone magnetic field total intensity map has been shown in figure 3. The used helicopter for the survey Bell244A and system characteristics are as follows:

Spectrometer:

- Exp loranium GR- 820

- (detector) down ward looking 16,71

- (detector) up war looking 4,21

- Mounted in helicopter

Magnetometer

-          Scintrex cesium sensor

-          Aerodat control console

Electromagnetic:

-          Aerodat 5 Frequency

-          Coaxial 935&4600 Hz

-          Coplanar 500 ,4175W&33000Hz

The spectrometer height from earth surface is 6m and magnetometer sensor 45m and electro magnetometer sensor 30m.

4-      The detailed information of civil mine exploration and geology organization:

In 1382, the civil exploration and geology organization talked action to buy the airborne geophysics devices by way magnetic, radiometry and electromagnetic from FUGRO Canada company . The purchased devices characteristics are as follows:

Minimag data acquisition system

Novatel GPS receiver

Cesium magnetometer

Exploration GR-820/Gpx 1025/256 Radiometric system Aerobat Electromagnetic sensor

Base station equipment:

-          MX 9212 GPS receiver

-          GEM systems GSM-19 proton Magnetometer

First project was begun with the presence of FOGRO company experts and the devices installation in sepal bell 214 helicopter in Dagenham in winter 1381, and after the expertise and technical knowledge Transition and with mounting devices and Lamely helicopter of helicopter service organization, the project continuation fulfilled by internal experts in 1382. The project performance processes consist three process, data survey, their processing, interpretation.

-          Data Survey:

First process of flight lines design is with taking the following notes:

    Air survey’s , which it usually performs along parallel lines series with same distances, are taken for the lines perpendicular to geology structures so that the most features are intercepted by lines. The lines series also become perpendicular to main lines with more distances, which it is called tie lines, the tie line spacing is usually designed one-fifth or one-tenth ration of flight lines distance.

The distance between lines depend on the exploration process. In more detail process in exploration, we design lines near each other. The flight height play an important role in data precision. The most geophysics methods encounter with the height rise, and the received signal from earth is attenuated, on the other had, due to the restriction in selecting the cable length linked to sensors and the limitations which topography applies in some area, we can not practically approach to earth more than limit.

In Dame Han project, the flight lines distance has been 200 and 400m , and the helicopter flight height from earth surface 60m. As the electromagnetic sensor consists three coplanar coil with frequencies 875, 4920, 33500 Hz and two coaxial xoil and with frequency 927 and 4490 Hz, and the magnetic sensor has been put to the spacing 45m from the earth. The minimal and Exploration devices have been built in helicopter.

Of course, These coordinates have error due to the helicopter movement, which it is corrected by GPS located in base station. Beside height which is recorded by GPS, one radar altimeter, which it has been mounted under helicopter, records the helicopter distance from earth surface with transmitting wave to the earth at every moment. Barometer altimeter also exists inside helicopter which it records the height from sea surface with the air pressure measurement at every moment.

-          Data processing:

Applied processing’s in magnetic, electromagnetic and radiometry raw data are as follows:

Magnetic data processing

         Spike removal

   Lag correction

  Diurnal correction

   IGRF removal

  Tie line leveling

 Vertical gradiest calculation

 Pole reduction

Radiometric data processing:

-          Live time correction

-          Cosmic correction

-          Aircraft background removal

-          Radon background removal

-          Compton stripping correction

-          Altitude attenuation correction

-          Applying spectrometer correction

-          Radiometric ratios

Electromagnetic Data processing:

-          Filtering

-          EM leveling

-          Apparent receptivity

-          Ejaculation

Airborne geophysics data interpretation

The geophysics characteristics enable to provide the geology information about mineralization processes nature, which it doesn’t appear by other exploratory methods , as the compound of these geophysics features with other exploratory methods results such as structure geology, surface geology, land sat, Radar sat, geo chemistry help to understand better case under consideration to ore explorer.

In general , the geophysics information interpretation consists two processes as follows

     Qualitative interpretation:

 

In qualitative interpretation, the geophysics data is used by way of magnetic from the following pictures:

-          Total magnetic field intensity color picture, counters and flight lines for displaying the measured data

-          Color picture and pole reduce magnetic field contours for interpreting the regional structures and low depth igneous masses sources.

-          Color picture and first derivative counters perpendicular from reduce magnetic field to polarized and also magnetic picture after applying high pass filter for determining the contacts, structure and surface sources.

-          Color picture and analytic signal counters for determining the magnetic rocks position without taking magnetic tendency angle and typical remaining magnetic from the above pictures as shown in figure 7.

The useful radiometry pictures in data qualitative interpretation:

-          Color maps and total count counter, potassium (%) , Thorium (ppm) and uranium (ppm).

-          Composite color picture (Ternary) from radio k,u,th,and ratio maps k/u,k/th,u/th,the sample of the above pictures have been shown in figure 8.

The useful electromagnetic pictures in data qualitative interpretation:

-          Receptivity mappings and Anomaly picking mappings which they determine the conductive beds rocks.

    Quantitative interpretation:

Information geophysics data quantitative interpretation give an anomaly to element about geometry, depth, gradient position and the inducing source direction, which it includes kinds of modeling methods of forward modeling and Inverse modeling, we can point to several samples:

Source Edge Detection (SED): Using data gradient, it determines at three direction the magnetic anomaly limit. (Blakely & Simpson, 1986)

Euler: Disconsolation algorithm for determining the anomaly source depth.

Node: It uses from magnetic responses for the structural modeling and geology.

Maxwell: Elm data modeling

Spectral airborne method:

Using hyper spectral airborne data at exploration:

As it is clear, the successes deposits exploration needs to multiple methods and tools. The geology, geochemistry, geophysics , remote sensing mappings and etc provide an important part of the required information. Alteration mappings made from the remote sensing is considered as one of importance exploratory function rings. These maps are the best deposits tracer specially aphanites deposits in surface, erosion (For example, oxidized) and with low surface grade.

As a sample , the hematite and / or high temperature clays detection completely is a key at porphyry copper deposits and epithermal gold exploration. To prepare these mappings with high precision by field sampling function and mineralogy analyzer (XRD) is an expansive method and in extent level it almost is impossible. Therefore using new exploratory tools like hyper spectral data can be a means for obtaining to this aim. Since beside very high precision, it is cost effective in time and cost.

Today, our borne hyper spectral sensors are used very much at the mineral exploration in the world. These sensors are mounted on the light aircrafts or even in some cases, on the helicopter, and regarding to low height in the flight, they have very much precision than the mounted sensors in satellite.

One of the most famous of these sensors is a very advance DBHS DEBFERS Hyper spectral sensor relate to DeBeers big exploratory company , it has an information 96 channel receiving power at remote and near infrared and visual wavelengths simultaneously. The reflective waves recording channels number in this sensor is very more than two ASTER and land sat sensors, and at spectral efficiency 2000-2500 Nm, they survey 32 spectral channels, which this spectral information amount provides the complete classification and recognition possibility of ores and altered mineral kinds as partial and precise.

  

So, DBHS sensor with 96 channel is the best tool for the geology- mineral purposes. Because the high signal ratio to it’s noise indicates the excellent quality spectrum, even we can record and interpret waves from ideologies and melanocratic units. This high quality spectral data, not only for determining ores type from view of the spectrum shape, has completely high quality, but we can use them for detecting the partial variations of the chemical compound and as well as the variations caused from ores recrystallization which they are considered as main factors for detecting and understanding the hydrothermal alteration zones. Therefore this enrich spectral information enable experts to recognize and detect many mineral and altered material. itself.

Very high capability of this sensor enable to provide the mapping more than 1300 km2 from earth surface with the spatial resolution 5m in every day , and the obtained data is processed and analyzed within several days , and it tends to prepare the very precise. Alteration maps and to recognize mineral potential.

In means that we can survey and process very extent level from big exploratory zone at very short time with very good resolution (3-5m) using this sensor, and we can detect a possible valuable deposits site with data analyze immediately. It is to say that no other technology able to supply this mineral information with very precise detail at short time.

From sampling viewpoint, we can mean this capability as one reading and spectral reflection (sampling) is performed from every 25m2 earth surface. Therefore, we can compare it with the field function which one sample is surveyed from each square 5×5m on earth.

Beside, with assembling and analyzing these data with other information layers like geology, structural geology. Geochemistry, geophysics and etc, we can take action to separate and detect the material and altered ores and index at the mineral exploration such as gold, silver, base metals, even, diamond, non- metallic ores and other many valuable minerals with very high precision.

So, we can say that this new technology has caused a big revolution in the mineral exploration and search and even oil and gas in the world. Because many world valid exploratory companies use from this technology at the mineral industry and the exploration.

            It is a necessary to be noted that base of this method , like other remote sensing methods, is that the materials and ores adopt and reflect the electromagnetic spectrum based on it’s internal structure and molecular bonds uniquely. So using pectoral methods and the electromagnet spectrum collection (for example at 0/5-2/5 micrometer range) and their interpretation, the ores dispersion map is prepared at wide scale.

Of course there are newer scanner like AVIRIS scanner which they also able to record the waves at more channels (224 channel between 0/4-2/45). It seems which extra channels are used more at plants and agricultural studies.

In general, the airborne hyper spectral methods provide the partial and precise information from many ores groups dispersion. So , the mineralization expectancy points are detected with high safety factor and more precision. Hence with regard to the scanners limitation the use of the hyper spectral methods is limited to a big companies, and it is less used at public and wide level. Therefore, it’s use , at areas which their exploratory history is a low and, they are new, tends to accelerate the exploration function and to decline costs. Because in the old and traditional methods, the obtained results may are not satisfactory due to the preliminary and even detailed exploration and search function performance very long time and the very expensive budgets spend.

As it was mentioned , a big exploratory companies like (Rio Tin to, Anglo Gold, Falconbridge) use from the hyperspetral methods at the exploration for a few years, and they have been succeeded to detect many mineral expectancy zones at wide area at short time. The exploration science researchers have also tested these methods power with the precision and they have emphasized it.

For example, rowan et al(2003) have used from Aster method at the advanced angelic alteration area detection at America Nevada kop rite region.

In other study , Berger et al (2003) have detected porphyry copper deposits at America Arizona region using spectral airborne method.

The hyper spectral studies can assemble with air magnetic studies, digit geology and topography maps and the mineralization recorded works, and provide more precise information at the mineral potential regions.

At Red mountain porphyry copper region, not only quartz- crinite-pyrite, pyrite-Angelic and prelatic alterations were detected, but the prepared alteration maps had more precision than maps which have been prepared by field studies.

So, it is proposed that with regard to the above cases and unique and high capability of the hyper spectral data, the trustee organizations and organs in preparing the geology maps and also the mineral exploration in the country optimize for determining the existing deposits and mineral sources distribution and position at the exploratory regions with the trust from being correct and precise of obtained results from new technology along with the exploratory projects position improvement at national level based on the performance time, cost effectiveness at budget and particularly the obtained results in comparison with other old and traditional methods.

Field spectroscopy using PIMA:

In this method, the ores spectral information is collected from the detected outcrops through the prepared mineralization maps from hyper spectral data, directly at dessert by PIMA portable (Infrared mineral analyzer) which it is a portable by geologistsSo, it is an available the more precise information from kinds of ores at the expectancy regions made from the hyper spectral surveys.

PIMA is a powerful at detecting the clay ores particularly. And even at cases it is more precise than XRD methods. It is mentioned that with surveying the hyper spectral information and their interpretation, the sampling is performed at field simultaneously, and it’s ores are detected by PIMA device.

After detecting the expectancy regions and performing the required flights at sections perpendicular to the desired ranges general trend, the field samplings perform for the performed reviews ground control and the made interpretation and approve from the hyper spectral surveys using PIMA device (portable Infrared mineral analyzer), which it is a portable by geologists, that the sample mineralization compound (qualitative and qualitative) obtain within a few minutes at dessert and without any preparation.

Last Update At : 09 January 2012