Transcript remote sensing to geology

REMOTE
SENSING
TO
GEOLOGY
The collection and
interpretation of
information about an
object without physical
contact with the object;
eg, satellite imaging,
aerial photography,
and open path
measurements.
Satellite remote
sensing has
become a common
tool to investigate
the different fields
of Earth and
environmental
sciences.
GEOLOGY
Remote sensing is
used as a tool to
extract information
about the land surface
structure, composition
or subsurface, but is
often combined with
other data sources
providing
complementary
measurements.
Remote sensing is not
limited to direct geology
applications - it is also
used to support logistics,
such as route planning for
access into a mining area,
reclamation monitoring,
and generating basemaps
upon which geological
data can be referenced or
superimposed.
Geological applications of remote sensing include the
following:
 surficial deposit / bedrock mapping
 lithological mapping
 structural mapping
 sand and gravel (aggregate) exploration/ exploitation
 mineral exploration
 hydrocarbon exploration
 environmental geology
 geobotany
 baseline infrastructure
 sedimentation mapping and monitoring
 event mapping and monitoring
 geo-hazard mapping and planetary mapping
Geoenvironmental
research can help to
identify the causes of
these events, point
the way to
rehabilitation
measures, and lend
support for early
warning systems
Remote sensing
adds considerably
to this research by
providing a wide
variety of sensors
operated from
airborne and
satellite platforms.
The GARS Program
of UNESCO and
IUGS provides a
means of continually
investigating the
geological
applicability of
remote-sensing
techniques.
The multispectral
scanner images
from the first nonmeteorological,
civilian Earth
observation
satellites, the US
LANDSAT series
launched in 1972
The LANDSAT
images were
received
enthusiastically by
a small scientific
community, mostly
geologists,
oceanographers
and geographers.
The GARS Program,
jointly sponsored by
UNESCO and IUGS,
was inaugurated in
1984 (Weber, 1985)
LANDSAT-1,and
LANDSAT-4, containing
Thematic Mapper, was
launched, adding an
additional three bands
in the SWIR (shortwave infrared) to the
existing visible (VIS)
and near-infrared (NIR)
bands.
Remote sensing has
become a widely
accepted research
tool by almost all
Geological Surveys
the world over.
Why remote
sensing?
A synoptic view of
regional scale is a
much different
perspective than
point ground
observations
when trying to
map structural
elements.
Remote sensing
offers this
perspective and
allows a geologist to
examine other
reference ancillary
data simultaneously
and synergistically,
such as geomagnetic
information.
Remote sensing gives the overview
required to
1.Construct regional unit maps, useful for
small scale analyses, and planning field
traverses to sample and verify various
units for detailed mapping;
2.Understand the spatial distribution and
surface relationships between the units.
Remote sensing offers
this perspective and
allows a geologist to
examine other
reference ancillary
data simultaneously
and synergistically,
such as geo-magnetic
information.
Geologic Unit Mapping
Mapping geologic
units consists
primarily of
identifying
physiographic units
and determining the
rock lithology or
coarse stratigraphy
of exposed units.
Data requirements
Two different scales of mapping require slightly
different imaging sources and parameters:
1. For site specific analysis, airphotos provide a
high resolution product that can provide
information on differential weathering, tone, and
microdrainage. Photos may be easily viewed in
stereo to assess relief characteristics.
2. Regional overviews require large coverage area
and moderate resolution. An excellent data
source for regional applications is a synergistic
combination of radar and optical images to
highlight terrain and textural information.
Today, with each new satellite in space,
some of the previous work has to be
repeated in order to test the new
technologies. This has led to a wider
acceptance of remote sensing for
geological applications and it has found its
place among the disciplines of the earth
sciences.
Interpretation of the picture
The Navajo Sandstone
(a) is the brightest single unit in the scene, followed by the valley floor to the
east, much of which is covered by alluvium
(b). The Entrada
(c) and Wingate
(d) Sandstones are notably darker, as is the top surfaces of the Mesaverde
(e). Note that the Wingate "pinches" out along the Fold towards the bottom of
the image, which suggests that its dip steepens making its outcrop pattern
thinner. The Kayenta Formation
(f) is barely discernible in the image as a thin, darker tone, but the Chinle
(g), also darker, has a wider outcrop pattern, because it is thicker and less
steeply dipping. The Emery Sandstone
(h) has a darker tone than the overlying Masuk Shale
(i) because, in the field, it is dark brown (similar to the Dakota Sandstone seen
in the foreground of this picture from the ground).
These dark
features are
outspillings of salt
that have been
called "salt
glaciers".
Atlas Mountain system of
northwest Africa
Atlas Mountain system of
northwest Africa
The white sinuous band against a fold ridge
is a dry stream or wadi.
These are the highest mountains in Africa and resemble parts of the
Alps except that the vegetation is distinctly different.