MASA GEOLOGI WHY STUDY WHERE FIELD & LAB PETA GEOLOGI KEGUNAAN SKALA ASAS KAJIAN MASA NISBI MASA MUTLAK KAEDAH TAKRIF KAJIAN TAPAK
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 Pastpresent future TUAMUDA LAMA BARU Dulu kini masa depan
Konsep masa: Dari sudut pandangan 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)
PROSES PRODUK ENVIROMEN SEDIAKALA/ BERUBAH/ DIUBAH 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) Observation Hypothesis Prediction DecisionFalsification Confirmation Observation The progress Of science
Masa Geologi: nisbi (relative) 1.Principle of superposition 2.Principle of original horizontality 3.Principle of lateral continuity 4.Principle of cross-cutting relationship 5.Principle of inclusions 6.Principle of faunal succession Tujuan: Order events from oldest to youngest (meletak sesuatu peristiwa yang berlaku mengikut tertib dari tua ke muda)
Masa Geologi: mutlak (absolute) 1Methods relying on event in the geological record with strong annual cyclicity Tree growth rings Coral growth cycles Varves (annual clay sediment layers) 2Decay of radiogenic isotopes (using concept of half-life)
1Principle 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 A B C oldest youngest
2Principle 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)
3Principle 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
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
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-238Lead-2064.5 billion years Uranium-235Lead-207704 million years Thorium-232Lead-20814.0 billion years Rubidium-87Strontium-8748.8 billion years Potassium-40Argon-401.25 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 CO 2. 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
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 OBSERVATIONS
Permian PeriodPermian Period (286-245 mya) The supercontinent Pangaea began to break up. Pennsylvanian PeriodPennsylvanian Period (325-286 mya) Lush, moist forests inhabited by giant amphibians and Mississippian PeriodMississippian Period (360-325 mya) insects produced vast coal reserves. Devonian PeriodDevonian Period (410-360 mya) The first vertebrates conquered land during this "Age of Fishes.“ Silurian PeriodSilurian Period (440-410 mya) Fishes with jaws and insects evolved. Ordovician PeriodOrdovician Period (505-440 mya) The first vertebrates appeared. Cambrian PeriodCambrian Period (544-505 mya) An "explosion" of life produced the first hard-shelled creatures. Paleozoic Era
MESOZOIC ERA The Age of Dinosaurs Cretaceous PeriodCretaceous Period (146-65 mya) A meteor finished off T. rex and all the other Dinosaurs. Jurassic PeriodJurassic Period (208-146 mya) Sauropods were the largest land animals ever! Triassic PeriodTriassic 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!Holocene Epoch 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.Pleistocene Epoch
The Paleocene through Pliocene epochs make up the Tertiary Period. Pliocene EpochPliocene Epoch (5-1.8 mya) North and South America were joined together. Miocene EpochMiocene Epoch (23-5 mya) The first major grasslands appeared, along with kelp forests. Oligocene EpochOligocene Epoch (38-23 mya) The first marsupials evolved. Eocene EpochEocene Epoch (54-38 mya) The first grasses appeared. Paleocene PeriodPaleocene Period (65-54 mya) The first pines, palms and cacti evolved
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?