الفهرس 
General Statement
Topography and GeomorphologyOnly 14 pages are availabe for public view
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Abstract
Scope of The Present Study
The present work deals with the application of geophysical investigations for
mineral exploration purpose, two selected areas of different geological setting’s the first
area located in Korabkansi area south eastern desert, Egypt and the second area located
western Sinai, Egypt, This study use Integrating of more than geophysical method for
detection of the metallic minerals in two study area, our aim is to detect the outcropped ore
maximum depth and to detect if there are any subsurface existence of the ore not prevailed
on the surface.
Material of the study
To achieve the goals of this study we use the following:
Available geological and geochemical previous studies.
Available geophysical data Magnetic and resistivity&IP measurements with different
devices, other type of data like DEM data
Available software such as (oasis montaj (2015), arckmap v.10.1, res2dinv v.3.53, ix1d
v.3.5 …etc. )
Geological map of South Korabkansi from Egypt geological map (Conico 1987, sheet
NF 36 NE).
Geological map of the studied area showing main lithological units after EGSMA,
NARSS, UNDP, UNESCO (2005)
First Study Area: Korabkansi
Location
The first area of study comprises the basement rocks covering about 95 km2. It is
bounded by latitudes 22° 31΄ 06.4˝and 22° 38΄ 46.4˝ N and longitude 34° 58΄ 35.86˝ and
35° 02΄ 47.08˝ E
Geologic Setting
The Titanomagnetite ore body occurs as thin layers nearly vertical extending northsouth within the metamorphic ultramafic rocks which are characterized by tectonic fabrics,
textures and structures that reflect a history of deformation, however the central portion of the middle and northern part is dominated by Titanomagnetite layers alternating with
ultramafic rocks.
Interpretation of Geophysical Data of Korabkansi Area:
Magnetic Method
Qualitative interpretation
The Total Magnetic Intensity Map
The magnitude of magnetic anomalies varies greatly from place to another, the
anomalies vary from 37071 nT in the far east and far west of the study area to 42130
nT.
The magnetic gradient change in the studied area from one place to another, the
gradients are sharp in the middle and southwestern parts trending in most anomalies
north-northwest south-southeast, however the eastern and western parts characterized
by very low gradient.
The Reduced to The Pole Map.
The reduced to the pole map show a small deviation of the spatial location of the
anomalies from the original data after recalculating the data.
The reduced to pole map shows anomalies with magnitude range from -3707 nT to
4319 nT Most anomalies peaks maximas and minimas are shown in the middle
extending north west southeast direction, the high difference in magnetude between the
minimas and maximas of each anomaly refere to avery magnetized source.
The RTP shows another direction of the elongated anomaly caused by the
titanomagnetite ore body extending northeast southwest with smaller length relative to
the main anomaly in the area.
The First Vertical Derivative Map
The first vertical derivative enhances the location of the anomalies and focus in the
causative ore body.
The first vertical derivative magnetic map shows alternating positive and negative
values. The positive values reach up to 148 nT/m., while the negative values reach to -
249 nT/m.
Small anomalies on the map may refer to short wavelengths that may be related to small
ore bodies to the east and the westApparent magnetic susceptibility map
The values of the apparent magnetic susceptibility in this map vary in magnetude from
0.0174 to -0.0152 CGS units in. the negative and positve values of the magnetic
suscebtability calculated for the psitive and nigative part of the anomalies refere to a
very high magnetization character of the causative ore body
Downward Continuation Magnetic Maps
A series of downward sessions applied to the data to construct five downward
continuation maps started with depth (d) equal 10 m. to reach d equal 50 m, main purpose
is to detect the continuity and shape of the magnetized sources downward.
downward continuation map with d=10 m., and d=20 m.
The magnitude of magnetic anomalies increased around the main anomalies, the
effect of deeper source extended downward increased by increasing the downward distance
in the first map (d=10 m.) the magnetic values range from 6144 nT. to -7665 nT., while in
the other map ranging from 13866 nT. to -27746 nT.
Source Edge Detection (SED) Maps
Peaks plotted over the RTP map to trace the geological contacts around the main source
anomalies, The symbols are coincident with the outlines of the anomalies, the direction
of gradient also is coincident with those of anomalies.
Peaks plotted over the total horizontal gradient map to show the peak location, and take
the contact elongation direction. The edge detected from the total horizontal gradient
to highlight the source itself.
Quantitative Interpretation
The main purpose of quantitative interpretation is to mathematically calculate the
magnetic source parameters (location, depth, magnetic susceptibility, and direction).
Two-dimensional radial averaged power spectrum
The 2-D radial average power spectrum technique give a simple view about the
depth distribution at the whole area. the calculated depth of magnetic anomalies in the area
under study into two divisions the shallow population with depth ranging from zero to 8m.,
the deep sources are reach 50 m. from ground surface. Magnetic Profile Inversion
The main function of profile inversion is to adjust the parameters of a simple
geometrical model of a magnetized body, to give the “best fit” between the observed data
and the calculated anomaly of the model, the magnetic anomalies in the total intensity
profiles have been modeled using the Geosoft program (2015), assuming field strength is
40087 nT., inclination 31.4◦ and declination 2.7◦. The depth of magnetic source (ore body)
appears to be ranging from 1 to 50.1 m. from ground surface.
Extended Euler deconvolution depth calculation
The extended Euler deconvolution process has two stages first Estimation of
sources using standard Euler deconvolution process then Enhancement of the results by
running Hilbert transformation.
The orientation of source bodies taking major direction north-north west south-south
east and a minor direction in the middle of the study area perpendicular to that direction
as the titanomagnetite ore body is appear on the ground surface the estimated dykes
representing the ore body and its vertical extension
The depth to the top of magnetized bodies calculated for this method ranging from -5
m down to -107 m. from ground surface.
2-D Depth Magnetic Calculation Using 2-D Analytical Signal
The orientation of source bodies taking major direction north-north west south-south
east and a minor direction in the middle of the study area perpendicular to that direction
as the titanomagnetite ore body is appear on the ground surface the estimated dykes
representing the ore body and its vertical extension.
The calculated depth to the top of magnetic sources for this method ranging from +1.1
m down to -79.9 m. relative to ground surface.
3-D Euler Deconvolution for The Magnetic data.
Euler map with Structural index equal to zero
The Euler solutions are calculated by applying structural index (SI) equal to zero to
detect magnetic contacts and (SI) equal to one to detect the possible dike locations.Most of shallow contacts extend in the NNW-SSE direction, these lineaments increased
in the middle of the study area. So, most of these lineaments match with the surface
outcrops of titanomagnetite in the area
In the Euler map, the obtained depth values by using structural index equal to zero
range from less than 1 m. to more than 40 m. from ground surface.
Euler map with Structural index equal to one
Structural Index =1 is used mainly to detect and calculate depth to dikes or in our
case the vertical prismatic ore body in the area under study.
The deeper clusters are concentrated in the eastern, and the western sides of the studied
area, the shallow clusters forming trends north-northwest south-southeast this is the
main anomaly trend where outcrops of titanomagnetite have the same direction.
The depth results estimated by using structural index equal to one ranging from zero to
more than 60 m. from ground surface.
Source Parameter Imaging (SPI)
The magnetic sources depth values estimated by this technique range from -9 m. to -
380 m but the mean range from -9 to -92 m. from ground surface, the shallow and deep
values are more coincident with different methods.
The traced ore outcrops location during field work matches the shallowest depth of top
magnetic sources.
Multi-Scale Edge Detection
multiscale edge analysis tool finds local maxima points of the total horizontal
derivative for many upward continuations of data, if your survey covers a small prospect.
The amplitude ranging from -150 to +300, distribution of connected points with the
same amplitude refer to continuity of the contact interface .
The worms plot over depth map from two different techniques to show the relationship
between magnetic sources and magnetic contacts downward .
Interpretation of Geo-Electric Data
Vertical electrical sounding
Electric resistivity measurements were applied using Vertical Electric Sounding
(VES) technique to detect the thickness of the conductive Titanomagnetite geologic zone within the study area, the total number of VES is 7. Interpretation and inversion applied
for each VES as follow.
VES No.1
The inverted resistivity data and its equivalent model for VES 1. The model shows
4 layers, the presence of low resistivity layers indicates mineralization zone, low
resistivity’s layer ranging from 38 to 54 Ω, with maximum thickness about 112 m, the high
resistivity value related to high fractured weathered top layer and to the gabbroic host rock
VES No.2
The inverted resistivity data and its equivalent model for VES 2 shows 4 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer
ranging from 19 to 64 Ω, with maximum thickness about 73.6 m, the high resistivity value
related to high fractured weathered top layer and to the gabbroic host rock
VES No.3
The inverted resistivity data and its equivalent model for VES 3 shows 4 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer
ranging from 36 to 156 Ω, with maximum thickness about 71 m, the high resistivity value
related to high fractured weathered top layer and to the gabbroic host rock.
VES No.4
The inverted resistivity data and its equivalent model for VES 4 shows 4 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer
ranging from 17 to 109 Ω, with maximum thickness about 101.5 m, the high resistivity
value related to high fractured weathered top layer and to the gabbroic host rock.
VES No.5
The inverted resistivity data and its equivalent model for VES 5 shows 7 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer
ranging from 34 to 276 Ω, with maximum thickness about 48.7 m, the high resistivity value
related to high fractured weathered top layer and to the gabbroic host rock.
VES No.6
The inverted resistivity data and its equivalent model for VES 6 shows 4 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer 206 Ω, with maximum thickness about 125.2 m, the high resistivity value related to high
fractured weathered top layer and to the gabbroic host rock.
VES No.7
The inverted resistivity data and its equivalent model for VES 7 shows 7 layers, the
presence of low resistivity layers indicate mineralization zone, low resistivity’s layer
ranging from 6 to 101 Ω, with maximum thickness about 95.2 m, the high resistivity value
related to high fractured weathered top layer and to the Gabbroic host rock.
Interpretation of Dipole-Dipole Geo-Electrical Cross-sections
Two electrical imaging methods which are 2-D resistivity and induced polarization
are chosen for this study. 2-D resistivity method is used to identify the ore bodies from
surrounding rocks by using the resistivity value contrast whereas IP method is used to
differentiate between massive and disseminated ore by differentiating the chargeability of
subsurface
Dipole-Dipole Cross-Section No.1
The profile length is 315 m. and reach maximum depth about 46 m., resistivity
value of the model ranging from 0 to 21500 Ω, from the visual inspection the resistivity
distribution indicate dike like low resistivity body likely to be Titanomagnetite ore body.
Dipole-Dipole Cross-section No.2
The profile length is 315 m. and reach maximum depth about 46 m., from the visual
inspection the resistivity distribution indicates main body likely to be Titanomagnetite ore
body, the IP model from chargeability values we can indicate two main ore body and
several disseminated small lenses
Dipole-Dipole Cross-section No.3
The profile length is 315 m. and reach maximum depth about 46 m., from the visual
inspection the resistivity distribution indicate dike like low resistivity main body likely to
be Titanomagnetite ore body, from the IP model from chargeability values we can indicate
main ore body and several disseminated small lenses with high chargeability value.
from analysis of resistivity and IP models of the three profile we can describe 5
main rock units in general form, first unit is the upper most weathered and fractured zonewhether it contain ore or not usually give high resistivity and low chargeability, water
saturated zones usually give the smallest resistivity with no chargeability, massive ore body
signature gives a very low resistivity with high chargeability
Second Study Area: Wadi Al Sahu Area
Location
The second area selected for this study is bounded by latitudes 28º 58΄ 13˝ and 28º
59΄ 5˝ N and longitude 033º 22΄ 15˝ and 033º 23΄ 4.5˝ E. located west Sinai near to Abu
Zeneima town, Egypt.
Geologic settings
The manganese-iron ore mainly occur within The Um Bogma Formation represents
the carbonate dominated succession (40 m thick) of Early Carboniferous age exposed in
the Um Bogma area and its surroundings in west-central Sinai, the manganese-iron ore
present as small lenses
Interpretation of geophysical data of Wadi al Sahu area:
Magnetic method
Qualitative interpretation
The Total Magnetic Intensity and The RTP Maps
The total magnetic anomaly map ranging from (-504 to 50 nT.), the anomalies
distributed mostly in the west and middle of the measured area
Magnitude of the reduced to the pole map doesn’t change a lot it ranges from (-584 to
117 nT) the distribution of anomalies doesn’t change a lot from its location in the total
magnetic anomaly map but the maxima of anomalies
The Vertical Gradient and The Total Horizontal Derivative Map
The magnitude of vertical gradient map ranging from (-316.6 to 836.7 nT/m.) the mean
data ranging from (-6.8 to 8 nT/m), in the total horizontal gradient it ranging from 0 to
72.8 nT/m. and the mean gradient ranging from 0 to 5.8 nt/m.,
Source Edge Detection (SED) Maps
Peaks plotted over the RTP map to trace the geological contacts around the main source
anomalies, these contacts show some trends. The symbols are coincident with theoutlines of the anomalies, the direction of gradient also is coincident with those of
anomalies.
Peaks plotted over the total horizontal gradient map show the peak location. The edge
detected from the total horizontal gradient grid so plotting the solution on this map well
highlight the source itself.
The Analytical Signal Map.
The magnitude of the analytical signal map ranging from 0 to 129.1 nT/m. the higher
magnitude located in the central part of the studied area, to the north-west, and to the
south west
Small anomalies are dispersed around the area but it’s not of economic importance, a
present mine location is coinciding with one of the high amplitude body.
Quantitative Interpretation of Magnetic Data
The main purpose of quantitative interpretation is to mathematically calculate the
magnetic source parameters (location, depth, magnetic susceptibility, and direction).
2-D Depth Magnetic Calculation Using 2-D Analytical Signal
The calculation made using two methods, first by selecting profiles along the major
anomalies in the gridded dataset and calculating the depth by analytical signal
The depth calculated for a selected anomaly ranging from -2 to -20 m. from ground
surface.
The depthcalculated using the whole measured data the calculated depth in the second
session is ranging from -2 to -21.1 m. from ground surface.
3-d Euler deconvolution for the magnetic data.
Euler map with Structural index equal to zero
Most of shallow magnetic contacts extend in the NE-SW direction, also the NW-SW
direction are present
In the Euler map, the obtained depth values by using structural index equal to zero
range from less than -1 m. to more than 5 m.
Euler map with Structural index equal to one
The deeper symbols clusters are concentrated in the northwestern, southwestern, and
central parts of the study area. The depth results estimated by using structural index equal to one ranging from -4 to
more than -10 m. from ground surface.
Source parameter imaging
The anomaly depth values estimated by this technique range from 1.8 m. to 10 m. from
ground surface, the deep values are more coincident with different methods.
There are three main groups of magnetized bodies in the central part, northwestern, and
in the southwestern part.
3-D Analytical Signal
In this technique we use the dipole peak selection tool available by oasis montaj (2015)
we can summarize the result.
The depth calculated to the top of each dipole source ranging from -0.1 to -3 meters
from ground surface is very low in magnitude relative to other methods.
Interpretation of Dipole-Dipole Cross-Sections
Two electrical imaging methods which are 2-D resistivity and induced polarization
are chosen for this study. 2-D resistivity method is used to identify the ore bodies from
surrounding rocks by using the resistivity value contrast whereas IP method is used to
differentiate between massive and disseminated ore by differentiating the chargeability of
subsurface.
Dipole-Dipole Cross-Section No. 1
The resistivity model is shown with topography, the profile length is 395 m. and
reach maximum depth about 25 m. a supposed lens with length is about 180 m. and its
thickness vary from point to point reaching the maximum thickness about 15 m.
Dipole-Dipole Cross-Section No.2
The total length is 315 m. and reach maximum depth about 25 m the resistivity and
IP Value distribution indicate dike like low to high resistivity main body likely to be
disseminated conductive ore body ranging in width from 5 to 20 m. and thickness 20 m.
Dipole-Dipole Cross-Section No.3
The total length is 235 m. and reach maximum depth about 30 m. we can indicate
patchy low to high resistivity bodies with relatively high chargeability relative to previous
cross-sections likely to be disseminated manganese-iron ore.Integrated Interpretation Between Magnetic and Geo-Electric Data
Using GM-sys program within Oasis Montaj (2015) we invert profiles along each
dipole-dipole cross sections, the three models can be summarized as following.
All three models generated by magnetic inversion are similar to detected geo-electric
layers from the dipole-dipole inverted models.
CONCLUSIONS
The goals of this study are to evaluate and detect the presence and distribution of
Titanomagnetite and manganese-iron ores in both studied areas.
First study area: Korabkansi
The qualitative magnetic analysis detects that the orientation of the observed
Titanomagnetite mineralization trends are coincide with those detected subsurface, the
main trend is north northwest-south south east and minor trend perpendicular to that
trend to the east northeast-west southwest.
The result obtained with different method 2-d or 3-d depth estimation are very similar
both methods obtain the depth to the top of magnetic sources from 0 to maximum 100
m. using profile inversion of the magnetic data a relative source thickness is obtained
and ranging from 7 to 413 m. from ground surface, the magnetic source contact with
increasing depth estimated with multi-scale edge detection tool have been coincedent
with most of depth maps estimated from different methods and reveal that the vertical
dipping is decreasing downward and to the east
The vertical electrical sounding interpretation, we can identify 5 main lithological units,
the 1 st weathered top layer thickness is ranging from 0.9 to 1.6 m with relatively high
resistivity ranging from 291 to 10985 Ω. The 2nd rock unit is highly fructured unit
with thickness ranging from 1.7 to 7 m. with high resistivity ranging from 567.1 to
10985 Ω. The 3rd representing very low resistive zone likely to be massive
titanomagnetite ore bodies with thickness ranging from 2.4 to 82.1 m. and resistivity
ranging from 6 to 38 Ω the 4th rock unite are relatively high resistivity to the previous
rock unit and interpreted as dessiminated ore bodies with thickness ranging from 6.8 to
125.2 m.and resistivity ranging from 52 to 267 Ω the 5th rock unit is very high
resistivity ranging from 840 to 7973 Ω representing the massive ultramafic host rock. from the three dipole-dipole cross sections we can describe 5 main rock units in general
form, first unit is the upper most weathered and fractured zone whether it contain ore
or not usually give high resistivity and low chargeability, water saturated zones usually
give the smallest resistivity with no chargeability, massive ore body signature gives a
very low resistivity with high chargeability ,disseminated ore zones come with high to
moderate resistivity and high to moderate chargeability in the same time ,finally the
host rock mafic to ultramafic rocks related to the ophiolite mélange which is very hard
and solid so it occupy the highest resistivity and barely have no chargeability
Second Study Area: Wadi Al Sahu
All the qualitative calculations approved the occurrence of small dispersed anomalies
in the study area these anomalies supposed to be The magnetic anomalies of manganese
iron ore ,also the shape and destribution of the anomalies resemble the occairance form
of a mn-Fe deposits as lenses or patchy bodies within um bogma formation.
The quantitative magnetic analysis detects, depth obtained with different method 2-d
or 3-d depth estimation are very similar all methods obtain the depth to the top of
magnetic sources from 0 to maximum 20 m., the sources are very small size with width
range from 20 to 100 m. from ground surface.
The dipole-dipole cross sections interpretation detects 4 main rock units in general
form, first unit is the upper most weathered and fractured zone whether it contain ore
or not usually give high resistivity and low chargeability, massive ore body signature
gives a very low resistivity with high chargeability, sedimentary host rock always gives
moderate resistivity and no chargeability effect, finally the basement rock with High
resistivity and no chargeability
Finally, the results of this geophysical study could give an idea about the ore
minerals signature in different geophysical technique’s, we can confirm the presence of
Titanomagnetite in the subsurface as extension of the outcropped locations in Korabkansi
area and the results of the study confirm its economic validity, we can confirm the presence
of manganese-iron ore lenses in the subsurface of Wadi al Sahu area ,regarding that most
valleys are structurally formed in the area, so more attention should give to the subsurface
exploration for manganese-iron ore in the future.