View
58
Download
6
Category
Tags:
Preview:
DESCRIPTION
Geological Mapping in Exploration
Citation preview
9/11/2014
Exploration Geology @ PetMin 2014 1
GE – 03 Geological Mapping
GEOLOGICAL MAPPING IN EXPLORATION
By:Mega F. Rosana, Ir., MSc., PhD
Euis Tintin Yuningsih, ST., MT., Ph.D.Dr. Ir. Ildrem Syafrie, DEA.
Emi Sukiyah, Ir. MT.Yuyun Yuniardi, ST., MT.Adi Hardiono, ST., MT.
Ir. Cecep Yandri Sunarie., MengIr. Undang Mardiana, MT.
Aton Patonah, ST., MT.
Part 1: (2) INTRODUCTION Introduction Concept exploration
Part 2: (3) GEOLOGICAL MAPPING IN EXPLORATION Geological Mapping Remote Sensing
PART 4: (4) EXPLORATION GEOCHEMISTRY Stream Sediment & Heavy Minerals Sampling Soil Sampling Rocks Sampling Biogeochemistry, Hydrogeochemistry, Gasgeochemistry Assaying
PART 4: (2) EXPLORATION GEOPHYSYC Airborne geophysics Ground geophysics Submarine geophyscs
PART 5: (2) EXPLORATION DRILLING Type drilling Drilling method Logging
PART 6: (3) EVALUATION Seminar (Presentation, Groups Discussion) Mid Test Final Test Fieldtrip
Courses Outline
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 2
EXPLORATION METHODS
B. Ground Mapping
Topographic mapping
Aero‐geochemical surveys
Aero‐geophysical surveys
• Aeromagnetic
• Electromagnetic
• Radiometric
• Gravimetric
Preliminary/Regional mapping
• Scale 1 : 250,000 ~ 1 : 50,000
Detail mapping
• Scale 1 : 20,000 ~ 1 : 1,000
Exploration Geology @ PetMin 2014
A. Airbone Mapping
9/11/2014
Why make a map ?
The nature of Geological Mapping
Smart Mapping
Choosing the best
technique
Choosing the best scale
The use of satellite
navigation (GPS)
Exploration Geology @ PetMin 2014
GENERAL CONSIDERATIONS
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 3
Exploration Geology @ PetMin 2014
WHY MAKE A MAP?
Geological map is graphical presentation of geological
observations and interpretations on a horizontal plane
Geological map is graphical presentation of geological
observations and interpretations on a horizontal plane
Geological section is identical in nature to a map except that data are
recorded and interpreted on a vertical rather then a horizontal surface
Geological section is identical in nature to a map except that data are
recorded and interpreted on a vertical rather then a horizontal surface
Maps and sections are essential tools in visualizing spatial, three‐
dimensional, geological relationships
Maps and sections are essential tools in visualizing spatial, three‐
dimensional, geological relationships
9/11/2014
Exploration Geology @ PetMin 2014
WHY MAKE A MAP?
Making a geological map is invariably the first step in any mineral exploration
programs
Geological map is important control document for all subsequent stages of exploration and mining (including drilling, geochemistry, geophysics, geostatistics and mine planning)
Making a geological map is a fundamental skill for any exploration or mine geologist
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 4
Exploration Geology @ PetMin 2014
Constructed according to the theories of geology and the intellectual abilities of its author
Constructed according to the theories of geology and the intellectual abilities of its author
Presents a selection of field observations and useful to the extent that is permits prediction of things which cannot
be observed
Presents a selection of field observations and useful to the extent that is permits prediction of things which cannot
be observed
Two different kinds of geological map
• large‐scale “fact or observational or outcrop maps”
• small‐scale “interpolation made by remote sensed image data : satellite, radar, air photographs, aeromagnetic maps
Two different kinds of geological map
• large‐scale “fact or observational or outcrop maps”
• small‐scale “interpolation made by remote sensed image data : satellite, radar, air photographs, aeromagnetic maps
THE NATURE OF GEOLOGICAL MAP
9/11/2014
Exploration Geology @ PetMin 2014
SMART MAPPING
Geologist start the fieldwork with ideas about the geology which has to
be mapped
The ideas are developed from looking at published
maps; interpreting air photos, remote sensing; aeromagnetic data; aero geochemical data; or followed an intuitive
hunch
The mapping sequence depends on the postulated geology driven from the
ideas
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 5
Exploration Geology @ PetMin 2014
Air photo mapping
Mapping with plane table
Mapping on pegged
grid
Mapping with tape
and compass
MAPPING TECHNIQUE
9/11/2014
Exploration Geology @ PetMin 2014
CHOOSING THE BEST TECHNIQUE
Depends upon the availability of suitable maps bases on which to record the field
observation.
The ideal base is an air photographs
Satellite imagery provide suitable base for regional mapping
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 6
Remote sensing is the science of remotely acquiring, processing and interpreting spectral
information about the earth’s surface and recording interactions between matter and
electromagnetic energy.
GROUND
Alumbrera, Ar
SATELLITE
AIRBORNE
CUPRITE, NVGoldfield, NV
Pengumpulan data dari citra satelit dan sensor airbone. Kemudian data tsbt dikalibarasi dan diverifikasi menggunkan spectrometer di lapangan
Field Spectrometer
LANDSAT
HYPERSPECTRAL
Geological mapping procedure
Survey Establishing control points
Compass and tape traverse
GPS traverse
Fact geology data collection Pit and trench mapping Prospect scale surface mapping District scale mapping Use of field manual for standard symbols and
codes
Map generation and archiving Map scales
Map folio system
Map interpretation
GIS maps generation
12
12
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 7
Survey procedure Establishing control points
Establish one differential GPS control point for early stage mapping works. Tie all traverses from this point.
For grid mapping – establish corner points of grid using differential GPS or Total station EDM.
Compass and tape traverse To be conducted only if GPS cannot be used. Important in gridding if area has poor GPS
signal. Traverses should be corrected using CSS
GPS traverse Use Garmin 60Csx for 2‐d mapping in early‐stage
mapping works
Use differential GPS for gridding in open areas.
13
13
Exploration Geology @ PetMin 20149/11/2014
Mapping – fact geology data collection
Pit mapping map at 1:500 scale (100 metres per A‐4
map sheet)
project data from mid‐bench
map rock type by colouring the ground side of the bench line with appropriate lithology colour (field manual)
map alteration by colouring the air side of the bench line
indicate structural contacts (dip/dip direction) using appropriate symbol
sketch (or photograph) the bench face as an offset diagram parallel to the bench map.
14
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 8
Mapping – fact geology data collection
Trench mapping map at 1:100 scale (10 metres per A‐4
map sheet)
map the floor of the trench
colour the map based on lithology
describe features in long hand using abbreviations in field manual (format: texture‐litho‐alteration‐mineralisation)
indicate structural contacts using appropriate symbol
15
Exploration Geology @ PetMin 20149/11/2014
Organizational hints for efficient mappingFaults, joint and contact lithology measurement
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 9
Exploration Geology @ PetMin 20149/11/2014
Mapping – fact geology data collection
Trench mapping map at 1:100 scale (10 metres per A‐4 map
sheet)
map the floor of the trench
colour the map based on lithology
describe features in long hand using abbreviations in field manual (format: texture‐litho‐alteration‐mineralisation)
indicate structural contacts using appropriate symbol
sketch one wall of the trench as offset diagrams parallel to the trench floor map.
decide on the sampling cut (either along wall or floor) and interval
tabulate “from‐to” sampling interval on the A‐4 map
18
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 10
Mapping – fact geology data collection
Detailed prospect scale mapping map at 1:1000 scale (data plotted in field
book or A‐4 millimeter sheets and transfer to map folios in camp)
draw‐out configuration of outcrop as actually measured (use solid line for outcrop and dash lines for floats or subcrops)
colour the map based on lithology
describe features in long hand using abbreviations in field manual (format: texture‐litho‐alteration‐mineralisation)
indicate structural contacts using appropriate symbol
19
Exploration Geology @ PetMin 20149/11/2014
Mapping – fact geology data collection
District mapping map at 1:5,000 scale (plot data on a
1:5000 scale topo map), use GPS for locating in the field
sketch configuration of outcrop (use solid line for outcrop and dash lines for floats or subcrops)
colour the map based on lithology
describe features in long hand using abbreviations in field manual (format: texture‐litho‐alteration‐mineralisation)
indicate structural contacts using appropriate symbol
20
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 11
Map Generation and Archiving Map consolidation
Pit mapping: consolidate maps into 1:500 bench plans
Trench maps: plot trench maps onto 1:1000 fact map
Prospect scale mapping: maintain a folio map system (do not digitise fact maps, can be scanned and then register in GIS)
Map interpretation Pit mapping: Use overlays on the bench fact
maps to interpret geology (with structures) and alteration in separate sheets.
Prospect and district‐scale mapping: Use overlays of the same size as the map to interpret geology and alteration as above.
Generate interpretive sections at the same scale as the maps.
21
21
Exploration Geology @ PetMin 20149/11/2014
Mapping outcrops : use multiple overlays
Color separation is maintained by plotting :
Lithologic contacts, faults, veins, and other structural on base map
Pervasive alteration and alteration halos on the first overlay
Mineral or their oxidation products on second overlay
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 12
Map Generation and Archiving Map filing
Maintain an orderly filing system of hardcopy maps in the project office (hangers or map cabinets)
Map interps are to be digitised and included in the GIS files for the project
Ensure that file name of shape files are correct and updated every month with the central server
23
23
Exploration Geology @ PetMin 20149/11/2014
Exploration Geology @ PetMin 2014
Comparison of mapping techniquesMapping Technique
Scales Indications Advantages Disadvantages
Pace & compass
1:100 ~ 1:1000
Rough prospect map. Infill between survey points
Quick. No assistance and minimal equipment needed
Poor survey accuracy especially on uneven ground
Tape & compass
1:100 ~ 1:1000
Detailed prospect maps: Linear traverse maps. Mine mapping
Quick. Good accuracy. No preparation needed
May need assistance. Slow for large equidimensional areas
Grid 1:500 ~ 1:2500
Detailed maps of established prospects
Fair survey accuracy. Relatively quick
Expensive. Requires advance preparation.
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 13
Exploration Geology @ PetMin 2014
Mapping Technique
Scales Indications Advantages Disadvantages
Plane table 1:50 ~ 1:1000
Detailed prospect mapping in complex areas
High survey accuracy. No ground preparation required
Slow. Requires assistance. Geological observation and map making are separate steps
Topographic map sheet
1:2500 ~ 1:100 000
Regional mapping & reconnaissance where no photography available. Base for GPS observations
Accurate map base with regional coordinates. Height contours
Difficulty in exact location. Irrelevant map detail obscures geology. Not available in large scale
Air photographs
1:500 ~ 1:100 000
Ideal geological mapping technique at all scales
Geological interpretation on photo. Stereo viewing. Easy location on features.
Scale distortion. Expensive survey if standard coverage not available
9/11/2014
Exploration Geology @ PetMin 2014
CHOOSING THE BASE SCALEThe scale chosen for mapping controls the types of data which can be recorded and types of observations in the
field
Small scale map shows broad regional patterns of rock distribution and major structures
Intermediate range scale could be described as detailed regional mapping; ideal scale when combining geological
mapping with regional prospecting or regional geochemistry
Large scale map is appropriate for showing the features which directly control and localize ore
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 14
Exploration Geology @ PetMin 2014
Geological map at 1 : 50009/11/2014
Exploration Geology @ PetMin 2014
Geological map at : 1 : 25009/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 15
Exploration Geology @ PetMin 2014
Geological map at : 1 : 10009/11/2014
Exploration Geology @ PetMin 2014
THE USE OF SATELLITE NAVIGATION (GPS)
Ideal for regional geological mapping onto published map bases
Ideal for regional prospecting and regional and detailed geochemical and geophysical data collection
Some limitations should be noted :
• GPS needs an unobstructed line of sight to the satellite which provide the location signal
• Relying exclusively on GPS for navigation can create serious problems
• GPS cannot provide accurate positioning on air photographs
• Plotting latitude and longitude coordinates in the field is difficult
9/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 16
Exploration Geology @ PetMin 2014 Example of Tape and Compass map9/11/2014
Exploration Geology @ PetMin 20149/11/2014
9/11/2014
Exploration Geology @ PetMin 2014 17
REMOTE SENSING APPLICATION
Exploration Geology @ PetMin 20149/11/2014
Recommended