1
MINISTRY OF EDUCATION AND TRAINING
INSTITUTE OF MINE AND GEOLOGY
NGUYEN TRUONG LUU
APPLY THE MATHEMATICAL STATISTICAL METHOD
FOR PROCESSING, ANALYSING AIRBORNE
MAGNETICAL, GAMMA SPECTRAL AND GRAVITY
MATERIALS TO STUDY THE GEOLOGICAL STRUCTRURE
AND MINERAL DISTRIBUTION OF
PHAN RANG – NHA TRANG AREA
Major: Geophysic
Code: 62.44.61.01
RECAPITULATION OF GEOLOGYCAL DISSERTATION
HA NOI - 2011
2
This studying is executed at Geophysical genre, Oil and Gas
faculty, Institute of mine and geology
Guide-teacher:
1. Dr., Pr. Pham Nang Vu
2. Dr. Nguyen Tai Thinh
Critic 1:
Critic 2:
Critic 3:
Dissertation will be defended at Basic Jury,
Intitute of Geology and Mineral, Đong Ngac - Tu Liem - Ha Noi
At: h date month 2011
Can find out about dissertation
at Institute of Geology and Mineral
3
INTRODUCTION
1. Imperative of dissertation
* Air-geophysical survey method is applicated on the world-wide. In
some countries as Soviet Union (old), Canada, Australian,... they not only
application magnetical and gamma spectral method on airborne survey, but
also EM (electro-magnetical) method in big scale for mineral investigation.
Results of proccessing and interpretation airborne survey documents
(magnetical and gamma spectral in specially) contribute to geology and
assessing the mineral.
* In Viet Nam, from the year of 80 of last century, the magnetic – gamma
spectrual airborne survey was carried out; the gravity survey was carried out
on the ground in the separate projects with different scales.
From 1990 up to this time, Geophysical Division usually carry out
airborne suvey (magnetical – gamma spectral survey) at scale 1:50,000
combine with ground gravity survey at scale 1:100,000. Until now, we have
finished 100,000km2 (about 1/3 entire territory of Viet Nam). The airborne
magnetic – gamma survey areas concentrate from Thanh Hoa to Lam Dong
province. The ground gravity survey areas cover with almost the airborne
survey areas.
The results of airborne survey are contributed a lot for geological survey
and mineral assessing . Specially, finded out many new mines as Uranium
mine (in Quang Nam province); Fluorite (Binh Dinh province); Magnesite (in
Gia Lai province), Gold (Son Hoa); Gold, Tin (Ha Tinh, Quang Binh, Hue,
Lam Dong...)
Before, the geological, mineral documents of Phan Rang - Nha
Trang area in scale 1:50,000 are limited, because the area is covered
by thick friable sediments. Therefore, the geological structure and
mineral potentiality of this area are not distinctly.
The airborne survey and ground gravity survey documents were
processed, analysed with different levels and purposes.
4
However, up to this time, the application statistic and identifying
method base on well-known mines for forecasting, assessing mineral
potential for new survey area is not very good. Specially is choosing
physical parameters for indentifying for each mineral.
There for, it very necessary to study, develop existing documents
of Phan Rang – Nha Trang to define the geological structure and
distributed way and potential of mineral. And, it is very important for
reasonable programming and making plan for geological survey and
mineral investigation.
With the basics as above, Postgraduate choosed studying object:
‘‘Apply the mathematical statistical method for processing,
analysing airborne magnetical, gamma spectral and gravity
materials to study the geological structure and mineral distribution
in Phan Rang - Nha Trang area”.
2. Purpose
Apply logical the mathematical statistical method system for
processing, analysing airborne magnetical, gamma spectral and
gravity materials of Phan Rang - Nha Trang area for describe
geological structure and the way of mineral distribution.
3. Study scope and object of studying
Studying object: Proccessing and analysing the documents of
airborne survey: magnetical, gamma spectral with scale of 1:50,000;
documents of gravity ground survey with scale 1:100,000 and the
other relative documents for studying the geological structure, the
way of mineral distribution of Phan Rang – Nha Trang area.
Studying scope: From Nha Trang to Phan Rang with area 8220
km circumscribed by latitude : 11o33’43’’ ÷ 12o50’49’’; longitude:
2
108o37’01’’ ÷ 109o15’04’’
4. Studying content
5
- Collection the existing relative documents about goelogycal
structure, genres of mineral in Phan Rang – Nha Trang and relative area.
- Base on the documents of the industrial size mines, that we
know exactly to apply the statistic, idetify method for assessing the
prospect of similar minerals in studying area.
- Apply the method system for magnetical, gamma spectral and
gravity data proccessing, analysing; supplement the statistic, identify
method for studying geological structure, mineral prospect and the
way of mineral distribution of Phan Rang – Nha Trang area.
5. Documents for studying
- The airborne magnetical, gamma spectral documents scale 1:50,000
and ground survey gravity document scale 1:100,000 of Phan Rang – Nha
Trang and relative area. These documents are stored at Geophysical
Division;
- The geological, mineral documents in scale 1:200,000; 1:50,000; ore
genesis documents in scale 1: 1000,000; 1: 500,000; 1: 200,000 and the
documents of mines, ores, mineral assessing in the studying area and
relative areas. These documents are stored at Center of Information and
Archives geology (CIAG)
- The relative document of Nguyen Tai Thinh, Nguyen The Hung
about methods of geophysical materials proccessing and analysing.
- The documents in and outside Viet Nam about airborne geophysical
and gravity materials proccessing;
- The document s about airborne magnetic, gamma survey and the
results of studying of author, that relate to geophysical proccessing and
analysing.
6. Studying method
- Collect and classify the existing document about geology,
mineral of Phan Rang – Nha Trang for preliminary assessing
6
geological structural characteristic, prospective minerals in this area;
Chose the proccessing and analysing method systems.
- For the statistical, identify method: Study theoretical
fundamental, experiment on the mineral objects, on which we known
already to define the processing process for assessing mineral
prospect of similar mine.
- Study to chose appropriate identify models for the potential
mineral in Phan Rang – Nha Trang from the mines, that were known
already and there are similar geological conditions; Spectify the
parameters for each model.
- Study the used airborne magnetical, gamma spectral processing,
analysing systems for geological, mineral investigation and apply for
studying area.
- Collect and classify the results of processing and analysing; the
collective document to define geological structure, prospect and the
distributed way of minerals in studying area
7. Scientific and reality signification
*) Scientific sinification
- Effective apply the statistic and identify method to assess the
prospect of mineral by the similar mine, that were known; Improve
on systems methods for airborne magnetical, gamma spectral and
ground gravity materials; more reliable for geological interpretation
and assessing prospect of mineral.
- Defined the characteristic of hidden geological structure and
mineral prospect in Phan Rang – Nha trang area by airborne magnetical,
gamma spectral and ground gravity materials.
*) Reality signification
- The systems methods are effective for phan Rang nha Trang
area and may be applied for the other areas.
7
- Contribute to describe geological structure characteristic and
potential of mine; Orient to make plan for investigation an assessing
the mineral in PhanRang Nha Trang area.
8. New opinions of dissertation .
8.1. Effective apply the statistic, identify method and chosing
reasonable geophysical parameters base on the informations of well-
known existing mines to define similar mineral prospect in studing
area.
8.2. Defined the hidden geological structure of Phan Rang – Nha
Trang area; divide the area to circular structure and 4 structural
blocks: M’Đrak (I), Ninh Hoà (II), Don Duong (III), Ninh Hai (IV),
They are separateed by different direction faults.
8.3. Most prospect of minerals in Phan Rang - Nha Trang are:
Gold, tin, wonfram, molipden; As first step, defined the way of their
ditribution.
– Tin, wonfram concentrate in zone Khanh Vinh, Tap La – Nui
Dat of zone Nui Da Den. These relate to magma of Ca Na and Dinh
Quan complex.
- Gold, molipden, copper, lead, tin concentrate in zone Deo Ca,
Song Cho and most area of Nui Da Den zone.
8.4. Statstic – identify method contributes to improve the processing,
analysing system methods for airborne magnetical, gamma spectral and
ground gravity materials for geological survey and assessing mineral
potential. The processing result of Phan Rang – Nha Trang can be applyed
to the other area.
9. Theoretical poit defend
9.1. Choose the complex of parameters by geological, mineral, chemi-
geological characters of gold and tin for machematical statistic – identify
method to defind main mineral prospect in phan Rang – Nha Trang area.
8
9.2. By the combination of geological sign premiss and combination
of reasonable identify geophysical parameters defined that most prospect
mineral of Phan Rang – Nha Trang are: Gold, tin ; accompanying minerals
are wolfram, molipden . These minerals main concentrate in structure zone
Don Duong and 4 prospect zone:
- Tin, wolfram most concentrate in Khanh Vinh zone and Tap La –
Nui Dat area of Nui Da Den zone. These minerals relate to magma of Ca
Na, Dinh Quan complex.
- Gold, molipden, copper , lead most concentrate in Deo Ca, Song
Cho zone and almost area of Nui Da Den zone. These minerals relate to
magma of Ca Na, Deo Ca and Dinh Quan complex.
10. Arrangement of dissertation
Except the introduction and conclusion, there are four chapters in
dissertation.
Chapter 1: Overview about the airborne magnetic-gamma
spectral survey, ground gravity survey and their materials processing
and analysing in Viet Nam ;
Chapter 2: Geological, geophysical characteristics of Phan Rang
- Nha Trang area and surrounding.
Chapter 3: Mathematical statistic method system for processing
and analysing the magnetic – gamma spectral, gravity materials of
Phan Rang - Nha Trang area.
Chapter 4: District geological structure and forecast minerals of
Phan Rang – Nha Trang area by geophysical document.
Chapter 1
OVERVIEW ABOUT THE AIRBORNE MAGNETICAL – GAMMA
SPECTRAL SURVEY, GROUND GRAVITY SURVEY AND
MATERIALS PROCESSING, ANALYSING IN VIET NAM
9
1.1. Airborne magnetical – gamma spectral survey for
geological and mineral investigation
Nowadays, the airborne magnetic – gamma spectral survey and
it’s material processing are popular applyed. It effective for
geological, mineral investigation.
1.2. Actual state of airborne magnetical – gamma spectral
and ground gravity survey in Viet Nam.
Up to this time, the area, that is investigated by airborne
magnetic – gamma survey occupy 1/3 the territory of Viet Nam. It
main distributes form Hue to Phan Thiet – Lam Dong. And some
important mines were finded out as: Fluorite in Xuan Lanh; gold in
Son Hoa (Phu Yen province); Urani in Khe Hoa – Khe Cao (Quang
Nam province); Magnesite in Kong Queng (Gia lai province) and
gold, tin mines in Lam Dong, Kon Tum, Hue, Nghe An, Quang
Binh...
1.3. Overview about airborne magnetical – gamma spectral
and ground gravity survey document for geological, mineral
investigation.
1.3.1. Material Processing and analysing of projects
Interpret geology by airborne magnetic – gamma spectral document:
Base on the radioactive of single anomalies the result of ground
preliminary investigation and the excisting geological, mineral document
to defind mineral prospect of the anomalous zone. Defind the structure,
faults by the altered field of magnetic, gravity materials.
1.3.2. In the processing, analysing, collect and classify reseach
work
* Geological structure studying (most of small scale)
The geological structure studying base on the processing and
analysing the magnetic, gravity materials.
10
* Study processing, analysing method system for airborne
magnetic – gamma spectral and ground gravity document to rerve
geological, mineral investigation; purpose: classify geological
objects for geological map establish and endogenous mineral
forecast.
1.3.3. Achievements and main unrealized of processing –
analysing airborne magnetic – gamma spectral and gravity
materials
Up to this time, the airborne magnetic – gamma spectral and
ground gravity processing – analysing contributed for geological,
mineral investigation. However, there are some unrealized things as
above, that need to continue to study.
Chapter 2
GEOLOGICAL, GEOPHYSICAL CHARACTERISTIC OF PHAN
RANG – NHA TRANG AND SURROUND AREA
2.1. Geological, mineral characteristic of Phan Rang – Nha
Trang area
2.1.1.Excisting document
- Existing geological, mineral documents stored in Geophysical
Division and in Center of information and archives geology (CIAG).
2.1.2. Geological, mineral charateristic of Phan Rang – Nha Trang
2.1.2.1. Stratum
Acording the existing documents, there are 12 strata units, from
Proterozoi to Quaternary :
Kham Duc (MP+NPkđ), Mangyang (T2my), Dak Bung (J1đb),
Dray Linh (J1đl), Ea Sup (J2es), La Nga (J2ln), Deo Bao Loc (J3đbl),
Nha Trang (Knt), Dak Rium (K2đr), Don Duong (K2đd), Mavieck
(N22mv), Xuan Loc (QIIxl), quaternary friable sediments (Q)
2.1.2.2. Penetrated magma contents 4 complexs and in each
11
complex , there are 3 phases 1, 2, 3 .
Dinh Quan complex (G-GDi/J3đq), Deo Ca complex (GĐi-Gsy-
G/Kđc), Ca Na complex (G/K2cn), Phan Rang complex (Gp/Epr), Cu
Mong complex (Gbp/Ecm)
2.1.2.3. Tectonic: By Nguyen Xuan Bao, Almost of studying area
lay on MDrak and Kon Tum structural zone ; remainder lays on the
Phan Thiet auxiliary structural zone , Da Lat structural zone
2.1.2.4. Mineral: Mineral were discovered: Coal; Au, Sn, in
addition Fe, Mn, Cu, Pb, Zn, Mo, W and radioactive ores.
2.2. Geophysical characteristic of Phan Rang - Nha Trang area
2.2.1. Existing geophysical documents
Existing airborne magnetic – gamma spectral, ground gravity in
small scale document and the document of airborn magnetic – gamma
spectral survey in scale 1:50,000 and ground gravity document scale
1:100,000 of Phan Rang - Nha Trang , 2006.
2.2.2. Charateristic of geophysical fields
2.2.2.1. Characteristic of Bughe gravity anomaly: Represent the
Da Lat basin structure, deep faults, structural blocks.
2.2.2.2. Characteristic of Ta magetic anomaly: Represent fault
system, structural blocks and shallow geological formation.
2.2.2.3. Characteristic of gamma field contain: Radioactive
intensive , Uranium content, Thorium content, Potassium content are
differentiation.
2.2.3. Geophysical parameters of rock in Phan Rang - Nha
Trang area.
In studying area, for different rock, the indensitive parameter
little changes, but magnetic and radioactive parameter are different.
Application high technology and reasonable processing,
analysing with the existing materials will exactly describe geological
12
structure characteristic, the way of distribution and mineral prospect
of studying area.
Chapter 3
PROCESSING, ANALYSING STATISTIC MATHEMATIC
METHOD FOR AIRBORNE MAGNETIC – GAMMA SPECTRAL
AND GROUND GRAVITY MATERIALS OF
PHAN RANG – NHA TRANG AREA
3.1. Base for choosing the combination methods and processing
program geophysical matrerial.
For geological and mineral investigation of Phan Rang – Nha
Trang, we inherit the existing method and study suplement statistic –
identify method
Used software: COSCAD (Russian), ERMAPPER (Australia)
and Potential fied (USA).
3.1.1. Coscad software: It is program for geophysical documents
processing and analysing base on the statistical theory and spectral
analys. Features: Calcuate the statistic specific of field and anomalies,
classify the anomalies by the filters, detect anomalies, bedding
geological objects, identify the anomalies by complex of signs.
3.1.2. ER.Mappper software: ER.Mapper is software for model
image processing. It can be used for remote sensing and aerial
photograph…
Features: Processing by formulars and bedding by complex of
signs
3.1.3. Potential field software
Potential field (PF) is software of Geological Department of
USA. It bases on the processing, altering, analysing methods and
quantitative caculation with magnetical and gravity materials.
13
3.2. Processing, analysing method system for geological structure
studying
3.2.1. Main characteristics of statistic spectral of geophysical
field.
3.2.1.1. Association characteristic of geophysical field.
1. Multi – direction self-correlative function
Multi – direction correlative function is used to describer the
statsitic of geophysical field by area at nodes of equilateral grid.
2. Self-correlative function and structure correlation.
This is field altering with constant step
3.2.1.2. Specrum characteristic of geophysical field
Base result of amptitude and phase processing can separate the
amplitude anomalous group and phase anomalous group .
3.2.2. Separate field to components method
3.2.2.1. Multi-direction energy and Vine- Conmogorop filter: 2D
optimal energy filtre, 1D filter, optimal linear filter are calculating the
main value of filter and it’s convolution
in fild value window.
3.2.2.2. Main composition analysing method
It’s statstic analysing to defind the main information composition
in used signs.
3.3. Processing, analysing method system to assess mineral
prospect
3.3.1. Separate the anomalies, altered zone by geophysical
document and defind their radioactive chemic-geological essence
3.3.1.1. Separate anomalies, anomaly zone: Filter gamma field to
separate anomalies for difinding single anomaly (it’s intensive is
higher than back ground and lower than back ground); calculate
anomalous complex, the used signs are basic field and altered field.
3.3.1.2. Separate the anomalous zone
14
Separate the anomalous zone, in fact, is join the anomalies with
similar radioactive, spectral. In addition, intersted to type of
magnetical, gavity anomalies and contained geological environment.
3.3.1.3. Define geological essence of anomalous zone and
relative mineral: Compare the separated anomalous zone with the
existing geological, mineral, ore place, disperse, chemic-geological
accumulation hoop document;
Base determined signs, accurate the type of endogenous change
and relative mineral forecast.
3.3.2. Anomalous Detective methods
3.3.2.1. Opposite probably method
Opposite probably method is effective when statistic
characteristic of anomaly is known beforehand
3.3.2.2. Detect the anomalies by complex of signs method.
This method is used „to sweep“ on the material raft by determine
direction to detect anomalies in different directions.
3.3.2.3. Identify by standard sample method
For this method, most important is choosing reasonable sample
and identify parameters.
1. Choose sample:
In each studying area, the sample must be satisfied conditions: to
be mine, mineral zone or mineral node is investigated and assessed;
geological, mineral characteristic of choosing mine, mineral zone
have to resemble with geological, mineral characteristic of studying
area; similar about geophysical materials (field and scale; essential
are magnetic, gamma spectral material) ; the kind of mineral of
choosing sample have to agree with the kind of mineral (may be
existed ) in studying area.
2. Choose identify geophysical parameter
Choosing the geophysical parameters for similar identify mineral
15
objects is carried out on every sample. It is used for choosing
parameters of geophysical field, that appropriate object. This work is
executed in different parameters and sample until the result of
identify best correct reflect about knowing mineral object of sample.
The result is confirmed when the identifying is high confidence. In
detail: If 0 80%)
and correspond to the geological conditions of sample. Accumulated
disperse, chemi – geological hoops reglect in accordance with forecast
minerals; Investigated and assessed by field work and finded out mine,
mineral zones with industrial content
+ A2: Conditions for this class similar to A1’s but in the area,
mine, mineral zones with industrial content are not detected yet.
+ B: In these area, one or serveral conditions are not satisfying to
A2 class.
4.2.2. Endogenous mineral prospect in Phan Rang – Nha Trang
are
By the results of processing geological, physical documents, can
defind 4 prospective mineral zones: Deo Ca, Song Cho, Khanh Vinh, Da
Den mountain.
98
4.2.1.1. Deo Ca zone
In the Ninh Hoa structural block, most of rocks appertain Ca Na, Dinh
Quan, Deo Ca complexes or of Dak Bung, Nha Trang formations.
Single gamma spectral anomalies locate at North – West margin
of studying area. Their nature are K, U – K and mixed (at the West).
There are anomalies of ∆Qk, ∆Qu, Ju, Jth, ratio U/K, dominal U,
complexes and ratio F. The result of identifying by Da Ban, Tra nang
golden sample concured to ditributed area of gamma spectral
anomalies. Magnetical anomalous field - ∆T vary very strong, mostly
by the NE – SW and NW – SE directions.
There are geological signs of Au accumulation dispersion hoops,
Pb geochemistry dispersion hoops and mineralized places of Au, Mo;
Da Ban golden ore place. Main prospective minerals are Au, Mo, Cu, Pb-
Zn. There are 4 region in the zone, one of them ranked A2 class (Nui
Vung region) and 3 regions are in B class (Chu Dau, Chu Ninh, Chu
Ma Bai).
4.2.1.2. Khanh Vinh prospective zone
Khanh Vinh zone is located in the west of the survey area. It can
be seen as extensions of metallogeny zone Da Chay- North of Da Lat,
this zone is created mainly from magmatic rocks of Deo Ca, Dinh
Quan complexes, rocks of La Nga, Don Duong formations.
Gamma spectral field is lowest of all area. Single spectral
anomalies concentrated mainly in the east and south of area, their
nature are thorium-uranium, uranium-potassium, mixture. The index
F anomalies are concentrated in the east, which associated with
anomalies ΔQu. In the west almost F <1, and mainly parameter
anomalies are changed (Ju, Th/U). Magnetical Anomalous field
complicated changes. Results of mineral identification in by Da Thien
tin sample is quite suitable to metallogenic data, which available
existed in area.
99
There are geological signs of geochemistry dispersion hoop: Cu,
Pb, Sn, W and Cs accumulation dispersion hoop; no mineral point or
mineralization are detected before. Main potential forecasted are Sn,
W, Mo, Cu, Pb, Zn. There are seven main potential minerals in this
area, three regions ranked A2 class, and four regions ranked B class:
Man Han; Tieu Quan; Dien Linh; Chu K’Nia.
4.2.1.3. Song Cho prospective zone
Song Cho prospective zone is located in the east of airborn survey
area, this prospect is isometric and extend by direction of longitude,
almost concentrate in districts: Khanh Vinh and Ninh Hoa. This zone
is formed by magmatic rocks of the Ca Na complex, Deo Ca, Dinh
Quan and rocks of La Nga formations, Don Duong, Nha Trang.
Gamma spectral field rather higher. Anomalies are K, U, and U-
K; F, Jk, Ju are high and mustering. They concentrated mostly in
South – West area by result of identifying by Da Ban, Tra Nang Gold
samples. Anomalous magnetical field strong alters in North – East
region and stabilized in South – West region
There are geological signs of Sn accumulation dispersion hoops,
Pb geochemistry dispersion hoop. Previous results haven’t almost
detected any mineral point. Mineral forecast: Au, Sn, Cu, Pb, Zn. The
Cho river zone: have 4 Regions and one single area. They contain,
three regions ranked B: Dien Tan, Hon Ngang, Hon Khi, a region was
ranked A2.
4.2.1.4. Da Den mountain prospective zone
Da Den mountain prospect mineral is located in the southwestern
study area, which covers the total structure of Da Den Mountain ring.
This zone is composed of magmatic formation Đeo Ca complex, Dinh
Quan, Ca Na and rocks of La Nga formations, Don Duong, Nha
Trang.
100
Many single spectral anomalies of airborne gamma was found
and concentrated make round structure of the Da Den Mountain, they
have nature of potassium, mixed, uranium-potassium, uranium.
Anomalies of ΔQu content, index F are quite outstanding, while the
anomalous parameters represent less. Field magnetic anomalies ΔT is
complex, amplitude varies from moderate to very high levels.
There are geological signs of Au, Mo, W, Sn minerals point. The
ore place, which are concentrated in this zone, accumulation
dispersion hoop, Geochemistry Au, Sn, Cu, Pb, Zn were discovered
in study area. Forecasting main minerals are: Au, Mo, Cu, Pb, Zn, Sn,
W.
In zone, we can divide to 8 mineral prospects areas. They contain
five prospective areas class B: Red Mountain,Ta Luong, Hon Rong;
Tien Phuoc, Chuân Mountain and three prospective areas class A2.
Besides potential zones were showed, three areas have been
delineated independent potential mineral (Ca Tien mountaint and Đa
Hang), they were evaluated with the prospects mineral class at B.
Main mineral are: Au, Sn, W, Cu, Pb, Zn.
4.3. Field test results
Purposes of Field test is determination the reasonable and objective of
processing results, analysising results; complete zoning results and
assessing potential mineral. Tested areas are A2 class areas.
4.3.1. To Hap area - Son trung prospective area.
According to analysising results predict potential minerals: gold,
lead, zinc, ranked A2
4.3.1.1 Geographical location:
Studying region are in the districts: Khanh Son and Cam Ranh of
Khanh Hoa province, with survey area is 113km2.
101
4.3.1.2. Geological results
There are geological formations of La Nga, Don Duong; Magmatic
rocks of Dinh Quan, Ca Na, Deo Ca complex.
4.3.1.3. Minerals: Minerals have discovered: gold, copper, lead,
zinc, acsen in four areas: Co Village, three groups in the North, three
groups in the South and in Tap Doan 8 area. Among them, In Tap
Doan 8 area and Co village, mineral prospect are higher than in the
others
1. Co Village hydrothermal altered zone contains multi-metallic
mineralized sufur: Result of Au, Ag atomic absorbed analysing in the
region showed that Au achieved from 0.4 to 9.53g/T, Ag: from 1 to
187g/T, Cu: 20÷3222ppm, Pb: 25÷7500ppm, Zn: 25÷774ppm, Bi:
1÷217ppm, As: 20÷38095ppm.
2. Tap Doan 8 hydrothermal altered zone contains multi-metallic
mineralized sufur: Result of atomic absorbed analysing showed that
Au achieved from 0.4 to 1.73g/T, Ag: 1g/T, Cu: 7÷53ppm, Pb:
39÷435ppm, Zn: 61÷71ppm, Bi: 1ppm, As: 20÷75ppm
3. Three- groups in the North hydrothermal altered zone
contains multi-metallic mineralized sufur): Result of atomic absorbed
analysing showed that Au achieved from 0.4 to 10.07 g / L, Ag: 1 to
187g / T, Cu: 8 ÷ 608ppm, Pb: 89 ÷ 11429ppm, Zn: 14 ÷ 211ppm, Bi:
1 ÷ 275ppm, As: 20 ÷ 4900ppm.
4. Iron ore point bears gold in the east of the top 866 (three-
group in the South)
Result of atomic absorbed analysing showed that content of Au
achieved from 0.1 to 3.0 g/T, Ag has content: 1g/T, Cu: 9÷21ppm, Pb:
9÷54ppm, Zn: 14÷61ppm, Bi: 1÷67ppm, As <20pm .
4.3.2. Phuoc Tan region
4.3.2.1. Anomalous group 57: Located on Phuoc Hoa village,
Bac Ai district, Ninh Thuan province. Result of atomic absorbed
102
analysing showed that content of elements by ppm: Au: 0.1÷2.13;
Ag: 1÷24; Cu: 28÷53; Pb: 84÷108; Zn: 16÷30; As: 13333÷35833; Bi:
5÷317. Result of plasmatic analysing showed Content of elements by
ppm: Sn ≤ 20; W: 20÷337; Mo: 10÷11. Result of Calcined analysing:
2.4 ÷ 2.52g/T; Ag:10 ÷ 36g/T.
In brief, main minerals of Anomalous group 57 was: Au, As.
4.3.2.2. Anomalous group 75: Located on Pro'h village, Don
Duong district, Lam Dong province. Result of atomic absorbed
analysing by ppm are: Au: 0,1; Ag: <1; Cu: 205; Pb: 65; Zn: 49; As:
328; Bi: 33. Result of analysing plasma was measured by ppm: Sn <
20; W: 91 ÷ 211; Mo: 775 ÷ 1172. Result of analysing samples by
approximate quantitative spectral method for original rock by ppm
are: Sn ≤ 1; Mo: 1 ÷ 100; W: 1÷ 100; Cu: 2.5 ÷ 5; Pb≤ 1; Zn≤ 10.
Main minerals are: Au, Mo, W
Besides, in the region we have preliminarily checked and finded
out 12 regions, where manifest mineralization.
4.4. General assessing
According the results of geophysical data analysising, main
prospected mineral in Phan Rang - Nha Trang area are gold and tin,
accompanied mineral tungsten, molypden, copper, Pb, Zn. Localized
4 potential mineral zones, they are Deo Ca, Khanh Vinh, Cho river,
Da Den mountain zone and some separated potential area in the East,
East - South and South of surveyed area
CONCLUSION AND RECOMMENDATION
Conclusions
Base on the result of dissertation, we can conclude as below:
1. Effective application the mathematical statistics and identify
method for main kind of minerals in the area: tin and gold; to describe the
respect and rule of distribution of mineral of Nha Trang – Phan Rang area.
103
2. Mathematical statistics and indentify method can be used for
docment proccessing of similar areas.
3. Identified hidden geological structures of the Phan Rang – Nha
Trang area with reliability basic and objectification. Divide the area
into four blocks: M'Drak (I) Block, Ninh Hoa (II) Block, Don Duong
(III) Block, Ninh Hai (IV) Block. They are divided by the fault
systems with different trends.
In Nha Trang – Phan Rang area, most prospective mineral are gold,
tin. Associated mineral are W, Mo, Cu, Pb, Zn. They mainly
concentrated in Don Duong structural block and four mineral zones.
Concret:
- Potential Mineral is tin, tungsten which mainly concentrate in
Khanh Vinh and Tạp La – Nui Đat potential area of potential zones of
Nui Da Den. They closely related with magmatic formation of Ca Na
and Deo Ca complexes.
- Potential Mineral is gold, molybdenum, lead and zinc which
concentrate mainly in potential zones: Deo Ca, Song Cho, and mostly
area of potential zones of Nui Da Den.
The field experiment results have proved plausibility, objectivity,
reliability of the results of processing, analysising and forecasts about
prospects for minerals in Phan Rang - Nha Trang area.
Reached results clearly described the geological structures,
prospects and the way of mineral distribution to contribute for
orientation and plan to investigate and assess the mineral in Phan
Rang - Nha Trang area for next steps.
Results of the dissertation are not only scientific signification but
also practical signification.
Recommendations
With the results of the dissertation, the author has suggestions
104
- Apply the results of geophysical data analysing of this dissertation for
study similar regions.
- Continue to study the identify- statistical methods with additional
geochemical information, geophysical informations to identify mineral.
- Based on the results of the dissertation can make plan to investtigate in
large scale for the potential mineral area A2. Where, the main minerals are
Au, Sn, Mo and W for the Phan Rang - Nha Trang area.
105
LIST OF PROJECTS PROMULGATED BY AUTHOR
1- Nguyen Tran Tan, Nguyen Truong Luu (1992). Apply geophysical
methods in origin tin ore exploration in the west of Nghe An. Geological magazine
210-211; pages 38-84. Ha Noi.
2- Nguyen Tai Thinh, Nguyen The Hung, Nguyen Tuan Phong, Nguyen
Truong Luu (2000). Deep fault systems and divide structural zones by geophysical
data for centre part of VietNam. Geological magazine 258; pages 15-24. Ha Noi
3 - Nguyen Tai Thinh, Nguyen The Hung, Nguyen Truong Luu, Tran Đang
Ninh (2000). Processing analysis airborne magnetic and gravitational data and
results of dividing potential endogenous mineral areas midland region of VietNam.
Geosciences mineral Conference; pages 79-80. Ha noi.
4- Nguyen The Hung, Nguyen Tran Tan, Đo Tu Chung, Nguyen Truong
Lưu, Nguyen Tai Thinh (2001). System methods for Geophysical data Processing,
analysing to identify potential endogenous mineral and some results when apply
for Rao Nay – Hoanh Son region. Collection of scientific works Ha noi university
of mining and geology episode 35; pages 110-115.Ha Noi.
5- . Nguyen The Hung, Nguyen Tai Thinh, Nguyen Truong Luu, Đo Tu
Chung (2005). Ability of finding the original tin ore in Binh Dien area, Thua Thien
– Hue province. Collection of conference reports 60 years of geological sciences in
Vietnam; pages 632-3-637. Ha Noi.
6- Nguyen Truong Luu, Nguyen Tran Tan, Nguyen Duy Tieu. Airborne
magnetic-gamma spectral survey on scale 1:25.000 and 1:50.000 in Viet nam.
Collection of conference reports 60 years of geological sciences in Vietnam; pages
682-687. Ha noi.
7- Nguyen Tai Thinh, Nguyen Truong Luu, Nguyen The Hung, Đo Tu
Chung (2005). Golden Prospect in A pey – Adang (Thua Thien Hue) region by
geophysical data. Collection of conference reports 60 years of geological sciences
in Vietnam; pages 802-805. Ha noi.
8- Nguyen Tai Thinh, Nguyen The Hung, Nguyen Truong Luu, Đo Tu
Chung (2005). A methodologies processing, analysis Airborne magnetic-gamma
spectral data and gravity for the purpose of forecasting and looking for mineral.
Collection of scientific reports and technical Geophysical Vietnam conference;
pages 551-562. Ha noi.
9- Nguyen Truong Luu, Nguyen Tai Thinh, Quach Van Thuc, Ngo Thanh
Thuy (2007). Prospecting of mineral in Phan Rang - Nha Trang region by
geophysical data. Geological Magazine 298; Pages 48-59. Ha noi.
10- Nguyen Tai Thinh, Nguyen The Hung, Nguyen Truong Luu, ĐoTu
Chung (2007). Prospect of buried mineral sand in the Quang Nam - Quang Ngai
coastal area by airborne gamma-ray spectrometry data. Geological magazine
301; pages 30-38. Ha Noi.