Transcript L6 - School Of Materials & Mineral

FIELD & LAB
WHERE
MASA GEOLOGI
ASAS
KAJIAN
SKALA
KEGUNAAN
WHY STUDY
PETA
GEOLOGI
KAJIAN
TAPAK
MASA NISBI
MASA MUTLAK
KAEDAH
TAKRIF
AGE OF THE EARTH
Ancient rocks exceeding 3.5 billion years in age
are found on all of Earth's continents. The oldest
rocks on Earth found so far are the Acasta
Gneisses in northwestern Canada near Great
Slave Lake (4.03 Ga) and the Isua Supracrustal
rocks in West Greenland (3.7 to 3.8 Ga), but
well-studied rocks nearly as old are also found in
the Minnesota River Valley and northern
Michigan (3.5-3.7 billion years), in Swaziland
(3.4-3.5 billion years), and in Western Australia
(3.4-3.6 billion years).
Age of the universe
The age of 4.54 billion years found for the
Solar System and Earth is consistent with
current calculations of 11 to 13 billion
years for the age of the Milky Way Galaxy
(based on the stage of evolution of
globular cluster stars) and the age of 10 to
15 billion years for the age of the Universe
(based on the recession of distant
galaxies).
Konsep masa
Dulu
Past
kini
masa depan
present
TUA
LAMA
MUDA
BARU
future
Konsep masa: Dari sudut
pandangan
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Ahli sains masa lampau
Ahli sains masa kini
Ahli geologi/kajibumi masa lampau
Ahli geologi/kajibumi masa kini
Ahli sains Muslim?
Jurutera?
Uniformitarianism/Teori Keseragaman
Limits of the Human Imagination
Uniformitarianism/Teori
Keseragaman
• The present is the key to the past
Maksud:
Apa jua proses geologi yg berlaku pada hari
ini juga berlaku di masa yg lepas/lampau
Contoh: luluhawa, ledakan gunung berapi,
gempa bumi, hakisan, pengangkutan,
pemendapan, dll
• Revolution Number One
Observation as a Source of Knowledge
• Principle of Original Horizontality
• Principle of Superposition
Masa geologi
• Panjang & pendek
• Cuba memahami proses kejadian alam (fauna,
flora, manusia sebagai makhluk istimewa)
• Cuba memahami produk (kejadian mineral &
batuan, logam/bukan logam) untuk manafaat dunia
sejagat
• Cuba memahami persekitaran untuk kegunaan
manusia
• Bagi jurutera memahami ragam produk dan
persekitaran (perubahan yang akan berlaku yg
mungkin boleh mengubah struktur rekaan mereka)
Kitar batuan
Mana dia
proses?
Produk?
SEDIAKALA/
BERUBAH/
DIUBAH
ENVIROMEN
PROSES
PRODUK
Peranan jurutera? Mampukah mereka
memahami ragam persekitaran yang
berubah/diubah?
Kepentingan masa geologi
• Kajian proses dan produk
• Kajian persekitaran asal ke baru
• Kajian ragam proses-produk-persekitaran
KAJIAN TAPAK
(SITE INVESTIGATION)
KAJIAN TAPAK
(SITE INVESTIGATION)
• Memerlukan penggunaan Peta Geologi
dan Peta Topo => surface dan subsurface
geologi
• Peta: merakamkan taburan batuan dan
sedimen, persekitaran, rupa bentuk bumi,
air, aktiviti ekonomi (kuari, perlombongan,
pertanian, dll)
• Kegunaan peta: pelbagai (ketenteraan,
keselamatan, persekitaran tabii,
ecotourism,dll)
• Sebagai ahli sains asas, sains gunaan
atau jurutera, kita mesti menghargai
maklumat dan sumbangan yg dibuat demi
kepentingan bersama
• Jurutera mengolah enviromen tabii kepada
yg baru
• Perubahan yg dibuat menuntut kita ….
Jurutera mesti berupaya membaca peta
dan mentafsir (dari descriptive ke
interpretive science)
The progress
Of science
Observation
Hypothesis
Prediction
Confirmation
Decision
Observation
Falsification
Masa Geologi: nisbi (relative)
Tujuan: Order events from oldest to
youngest (meletak sesuatu peristiwa yang
berlaku mengikut tertib dari tua ke muda)
1.
2.
3.
4.
5.
6.
Principle of superposition
Principle of original horizontality
Principle of lateral continuity
Principle of cross-cutting relationship
Principle of inclusions
Principle of faunal succession
Masa Geologi: mutlak (absolute)
1 Methods relying on event in the geological
record with strong annual cyclicity
• Tree growth rings
• Coral growth cycles
• Varves (annual clay sediment layers)
2 Decay of radiogenic isotopes (using
concept of half-life)
1
Principle of superposition
(Prinsip supertindanan)
• States that in an undisturbed stack of
sedimentary strata the oldest layer is at
the base and the youngest at the top
C
youngest
B
A
oldest
2 Principle of original
horizontality (Prinsip pendataran
asal)
• States that sedimentary strata were
deposited in nearly horizontal layers
• If flay lying layers are observed to be
folded in a complex fashion, then folding
must have followed the deposition of the
layers
Sedimentary rocks formed as flat strata
(Principle of original horizontality)
strata
3
Principle of lateral continuity
(Prinsip keselanjaran sisi)
• States that sediments extends laterally
until it thins or pinches out against the
margin of the basin in which it is
accumulating
• Uninterrupted exposures – rare to find
=> necessary to correlate from one
exposure to the next to determine how
extensive some of these units really are
Enviroment of
sedimentary rx
4
Principle of cross-cutting
relationships
(Prinsip hubung silang)
• States that if unit or event A cuts across
unit or event B, then A is younger than B
Principle of cross-cutting
relationships
Masa nisbi
Susun lapisan dari paling tua ke paling muda
Tugasan: masa nisbi
Susun lapisan dari paling tua ke paling muda
Tugasan: Masa nisbi
Susun lapisan dari paling tua ke paling muda
Adakah sill ini lebih tua/muda dari
batuan dikelilingnya?
5
Principle of inclusions
• States that inclusions of rock A in rock B
must be older than rock B
6
Principle of faunal succession
(Prinsip jujukan fauna)
• states that fossil assemblages succeed
one another through time in a regular and
predictable order.
Index fossils
correlation
Correlation: stratigraphy
Unconformities (Ketakselarasan)
• In a stack of sedimentary layers, some of
them are missing through natural process
(such as weathering and erosion) across a
boundary. These breaks are called
unconformities (ketakselarasan)
unconformities
refers to the
surface between two layers that were not
laid down in an unbroken sequence
Types of unconformites
• Disconformity
• Angular unconformity
• Nonconformity
A disconformity is an unconformity in
which the upper set of strata (the younger
set) overlies an erosional surface
developed on undeformed (horizontal)
lower (older) beds.
These can be difficult to detect in the field
unless there is a change in sedimentary
facies between the upper and lower beds
An angular unconformity occurs when
younger beds are deposited on strata that
have been folded and eroded to produce a
flat depositional surface. This implies
deposition, followed by tectonism, erosion
and further deposition.
A nonconformity is an unconformity in
which the upper beds (younger beds)
overlie metamorphic or igneous rocks.
A nonconformity thus implies volcanism,
plutonism or tectonism to produce the
igneous and/or metamorphic rocks,
followed by erosion to a flat surface and
eventual deposition of sedimentary rocks
unconformity
Angular
Unconformity –
Siccar Point on
the
Berwickshire
coast ~ 60 km
east of
Edinburgh,
Scotland.
Revolution Number Two:
radioactivity
Formula to calculate time
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Half-life : time it takes for half of the Parent
to decay (change) to the Daughter
Uranium-235 -> Lead-207
Uranium-238 -> Lead-206
Thorium-232 -> Lead-208
Rubidium-87 -> Strontium-87
Potassium-40 -> Argon-40
Carbon-14 -> Nitrogen-14
• During the decay Heat is given off - this
is an important source of energy to
produce temperatures necessary for
partial melting.
• alpha decay - two protons and two
neutrons are emitted from the nucleus.
This reduces the atomic number of the
parent by 2 and the mass number of the
parent by 4. Uranium to Lead Schemes
• Electron capture - occurs when a proton
captures an electron and changes into a
neutron. The atomic number of the parent
element is decreased by 1 but the mass
number is unchanged :
• Beta decay - an electron is emitted from a
neutron in the nucleus changing the neutron
to a proton. This increases the atomic
number of the parent element by 1 but does
not change the atomic mass number :
Parent
Isotope
Stable
Daughter
Product Currently
Accepted Half-Life
Values
Uranium-238
Lead-206
4.5 billion years
Uranium-235
Lead-207
704 million years
Thorium-232
Lead-208
14.0 billion years
Rubidium-87
Strontium-87 48.8 billion years
Potassium-40
Argon-40
1.25 billion years
Separuh hayat C-14
N14
• 5700 years
N-14 is converted to C-14 in the earth’s atm.
C-14 bonds with oxygen to form CO2. Living
organism absorbs C-14, and as long as the
organism is alive the amount of C14 in its
structure remains constant. When the
organism dies no more C-14 ia absorbed and
the amount of C14 decreases as it devays
back to N14. The older the organism, the
smaller the amount of C-14
sesuai untuk organisma usia < 70000 tahun
Alat mass spectrometer
HASIL KAJIAN  KOLUM MASA
GEOLOGI (macam2 bentuk ada!)
GEOLOGIC
COLUMN
OBSERVATIONS
Life was largely confined to the sea from the
Silurian Period back through the Cambrian
and beyond
Plants and amphibians colonized land
during the Devonian.
The Mississippian and Pennsylvanian were
noted for exotic coal forests; Europeans
group them together as the Carboniferous
Period
Paleozoic Era
Permian Period (286-245 mya) The supercontinent
Pangaea began to break up.
Pennsylvanian Period (325-286 mya) Lush, moist forests
inhabited by giant amphibians and
Mississippian Period (360-325 mya) insects produced vast
coal reserves.
Devonian Period (410-360 mya) The first vertebrates
conquered land during this "Age of Fishes.“
Silurian Period (440-410 mya) Fishes with jaws and insects
evolved.
Ordovician Period (505-440 mya) The first vertebrates
appeared.
Cambrian Period (544-505 mya) An "explosion" of life
produced the first hard-shelled creatures.
MESOZOIC ERA The Age of Dinosaurs
Cretaceous Period (146-65 mya) A meteor
finished off T. rex and all the other
Dinosaurs.
Jurassic Period (208-146 mya) Sauropods
were the largest land animals ever!
Triassic Period (245-208 mya) Dinosaurs,
mammals and birds got their start..
• CENOZOIC ERA The Age of Mammals
• Holocene Epoch (11,000 years ago...to
today!
• Pleistocene Epoch (1.8 million-11,000
years) People evolved during the last "Ice
Age."The Pleistocene and Holocene are
the beginning of the Quaternary Period.
The Paleocene through Pliocene epochs
make up the Tertiary Period.
Pliocene Epoch (5-1.8 mya) North and
South America were joined together.
Miocene Epoch (23-5 mya) The first major
grasslands appeared, along with kelp
forests.
Oligocene Epoch (38-23 mya) The first
marsupials evolved.
Eocene Epoch (54-38 mya) The first
grasses appeared.
Paleocene Period (65-54 mya) The first
pines, palms and cacti evolved
Geological significance
Masa dinosaur pupus
• When did dinosaurs become extinct?
• Dinosaurs went extinct about 65 million years ago (at the
end of the Cretaceous Period), after living on Earth for
about 165 million years. If all of Earth time from the very
beginning of the dinosaurs to today were compressed
into 365 days (1 calendar year), the dinosaurs appeared
January 1 and became extinct the third week of
September. (Using this same time scale, the Earth would
have formed approximately 18.5 years earlier.) By
comparison, people (Homo sapiens) have been on earth
only since December 31 (New Year's eve). The
dinosaurs' long period of dominance certainly makes
them unqualified successes in the history of life on Earth.
What was the biggest dinosaur?
What was the smallest?
• The largest complete dinosaur we know of was Brachiosaurus ("arm
lizard"); it reached 23 m in length and 12 m in height (about the
length of two large school buses and the height of a four-story
building). Fragmentary leg bones and vertebrae of even larger
dinosaur species are known, but these skeletal remains are too
incomplete to determine their exact size. Several of these
(Argentinasaurus and Amphicoelias) might have been one and a
half to two times larger than Brachiosaurus. The smallest dinosaurs
were just slightly larger than a chicken; Compsognathus ("pretty
jaw") was 1 m (3 ft) long and probably weighed about 2.5 kg (about
6.5 lb). These three dinosaur types all lived during the Jurassic
Period. Mussaurus ("mouse lizard") was claimed as the smallest
dinosaur, but it is now known to be the hatchling of a dinosaur type
that was much larger than Compsognathus when fully grown. If birds
are advanced dinosaurs, then the smallest dinosaur would be the
hummingbird!
What was the biggest dinosaur?
What was the smallest?
KAJIAN TAPAK
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Surface geology
Subsurface geology
Engineering parameters
Environment
Mineral (logam, bukan logam)
Air tanah
Archeology (kajipurba)
Mineral
Batuan
Sedimen
air
Landforms for development
NEXT LECTURE
• DEFORMATION/CANGGAAN