2Learning objectives luluhawa 1 Apa itu 6 hasil 2 Bagaimana terjadi5 Impak/kesanluluhawa7 kepentingan3 Jenis2 luluhawa4 Faktor2 yg mempengaruhiluluhawa
3Luluhawa – suatu proses yang berlaku di permukaan bumi untuk memecah dan menguraikan batuan (break and decompose rocks) Enviromen: terhad kepada sejauh mana air tanah (groundwater) boleh menusuk masuk (penetrate) ke dalam permukaan bumi
4luluhawa Boleh dilihat sebagai destructive forces - yang memecah, mengurai, mengubah bentuk dan keadaan fizikal dan kimia batuanBoleh dilihat sebagai constructive forces – yang menghasilkan sedimen, membentuk batuan mendak, mineral, mendapan mineral, landform baru
5Fakta asas luluhawa Berlaku perlahan sepanjang masa Mengambil masa yang lamaSemua jenis luluhawa berlaku kadang2 serentak dan tak terpisah satu sama lain. Dipisahkan untuk memudahkan pemahaman sahajaKeadaan di keliling menentukan segalanya
71. Luluhawa fizikalMemecahkan batuan yang bersaiz besar kepada bahagian yang lebih kecilcontoh: wedging (pembajian), exfoliation (pengelupasan), thermal expansion (kembang haba), lelasan (abrasion), (wetting and drying (esp in shales), pressure release by erosion of overburden
8Luluhawa fizikalFrost wedging (pembajian ibun) – water expands when it freezes, breaking rocks into angular fragments; lazim berlaku dalam iklim temperat (ada ais)Nota: apabila air menjadi ais, isipadu meningkat sebanyak 10% => mebungkah (pries) batuan
11Luluhawa fizikal2 Exfoliation (pengelupasan) – bedrocks (batuan hampar) breaks into flat sheets along joints (kekar) which parallel the ground surface. This phenomenon is caused by expansion of rock when the pressure of overlying rock is removed by erosion => sometimes called unloadingApa itu kekar?
22Luluhawa fizikal3 Thermal expansion (kembang haba) – heat causes action; cooling causes contraction => expand and contract at different rate causes stresses along mineral boundaries. Repeated heating and cooling => batuan pecah
234 Lelasan (abrasion)Batuan menjadi lebih kecil hasi drpd pergeseran dan pelanggaran semasa terangkut, contohnya di dasar sungaiGlasial, ombak dan angin juga boleh menjadi agen lelasan
24Kelebihan kimia fizikal Luluhawa fizikal memecahkan batuan ke saiz yg lebih kecil => menyediakan lebih banyak luas permukaan batuan bersaiz kecil untuk tindakbalas kimia berlaku
252. Luluhawa kimiaMemecahkan batuan secara kimia dgn menambah atau menanggalkan (removing) unsur2 kimia, mengubah unsur2 tersebut menjadi bahan2 barucontoh: dissolution (pelarutan), hydrolysis (hidrolisis), oxidation (pengoksidaan)
26Luluhawa kimiaDissollution (pelarutan) – alters rocks by removing soluble minerals => soluble ions and insoluble ions => precipitate and crystallize (dalam tasik atau laut)Ex: pembentukan garam, batu kapur, travertineBatuan => ion larut/ tak larut => pemendakan
30Beberapa contoh t/b kimia Solution of carbon dioxide in water to form acidCO2 + H2O H2CO3 H+ + HCO3-Solution of calciteCaCO3 + CO2 + H2O Ca HCO3-CaCO3 + H+ HCO Ca HCO3-
31D. Chemical weathering of feldspar to form clay mineral 2KAlSi3O8 + 2H+ + 2HCO3- + H2OK feldsparAl2Si2O5(OH)4 + 2K+ + 2HCO3- + 4SiO2clay mineralSilica in solutionor as fine solidparticles
32Cara jurutera bahan mengungkap formula untuk memudahkan kefahaman K2OAl2O36SiO22KAlSi3O8Al2Si2O5(OH)4Al2O32SiO22H2O
33Luluhawa kimia3 oxidation – the process by which iron-bearing minerals (pyroxene, amphibole, biotite) weather to produce iron oxidesDi kawasan tropik iron bearing aluminosilicate => lateritic soils, red clayey soils
44Mineral stability in the weathering environment Mineral didapati tak stabil dalam enviromen tertentuMinerals which formed at high temperature and pressures are least stable in the weathering environment and weather most quicklyMinerals which formed at lower temperatures and pressures are most stable under weathering conditions
49Leaching/larutlesap: proses kimia yang menghasilkan unsur larut dan tak larut. Yang larut akan lesap ke bawah dalam profil tanah sementara yang tak larut akan terkumpul di bahagian atas profil tanah => warna membezakan lapisan tanahEluviation: removal of materials dissolved or suspended in waterIlluviation: horizon of maximum accumulation of suspended material or clayChelation: pembentukan kompleks kimia
61Tengok transparensi lain Gred luluhawa (weathering grade), kekuatan ekapaksi dan rock-soil ratioUCS(MPa) RSRGred VI tanah/soilGred V completely weathered <Gred IV highly weatheredGred III moderately weatheredGred II slightly weatheredGred I Fresh rockTengok transparensi lain
67Hakisan (erosion)The movement of weathered material from the site of weathering. Primary agent is gravity, but gravity acts in concert with running waterpergerakan bahan terluluhawa dari tempat luluhawa berlaku ke tempat ia ditemui
73Sambung => batuan mendak (lihat beberapa transparensi mengenai luluhawa)
74Batuan mendak Apa kesudahannya? kepentingan apa Bagaimana jenis2 terjadijenis2Ciri2 utamaDi manaPerubahan sebelum, semasa danselepas pembentukan
75Hasil drpd luluhawa ialah sedimen Sediment = loose particulate material (clay, sand, silt, gravel, etc.)Sediment becomes sedimentary rock through lithification, which involves:CompactionCementationRecrystallization (of carbonate sediment)
76Wentworth scale - grain size scale Particle name Particle diameter GravelBoulders > 256 mmCobbles mmPebbles mmGranules mmSandVery coarse sand mmCoarse sand mmMedium sand mmFine sand mmVery fine sand mm Silt 1/ /16 mm (or mm)Clay < 1/256 mm (or < mm) sesetengah buku guna takrif <2 mikron
81Hjulstrom CurveMenghubungkait vel-size dgn proses (1939)
82Clasts (larger pieces, such as sand or gravel) A. Terrigenous (also called detrital or clastic)Terrigenous sedimentary rocks are derived from the weathering of pre-existing rocks, which have been transported to the depositional basin. They have a clastic (broken or fragmental) texture consisting of:Clasts (larger pieces, such as sand or gravel)Matrix (mud or fine-grained sediment surrounding the clasts)Cement (the glue that holds it all together), such as:calciteiron oxidesilica
83Clasts and matrix (labelled), and iron oxide cement (reddish brown color)
84Sand: Grain size 1/16 to 2 mmSandstoneIf dominated by quartz grains = quartz sandstone (also called quartz arenite)If dominated by feldspar grains = arkoseIf dominated by sand-sized rock fragment grains = lithic sandstone (also called litharenite or graywacke)
90Silt: Grain size 1/256 to 1/16 mm (gritty) Siltstone
91Clay: Grain size less than 1/256 mm (smooth) (< 2 micron) Shale (if fissile)Claystone (if massive) Note: Mud is technically a mixture of silt and clay. It forms a rock called mudstone (or mudshale if fissile).
94B. Chemical/biochemical Sedimentary Rocks This group includes the evaporites, the carbonates (limestones and dolostone), and the siliceous rocks. These rocks form within the depositional basin from chemical components dissolved in the seawater
95Evaporites - The evaporites form from the evaporation of water (usually seawater). Rock salt - composed of halite (NaCl).Rock gypsum - composed of gypsum (CaSO4.2H20)Travertine - composed of calcium carbonate (CaCO3), and therefore, also technically a carbonate rock; travertine forms in caves and around hot springs.
96Bonneville Salt Flats of the Great Salt Lake, Utah Bonneville Salt Flats of the Great Salt Lake, Utah. The lake bed is covered with rock salt which gives it the white color. The salt is mined by the Morton Salt Company.
99Two minerals are dominant in carbonate rocks: Carbonates - The carbonate sedimentary rocks are formed through both chemical and biochemical processes. They include the limestones (many types) and dolostones.Two minerals are dominant in carbonate rocks:Calcite (CaCO3) (batu kapur)-mudah berbuih dgn asid lemahDolomite (CaMg(CO3)2) – perlu digores jadi serbuk, baru bertindakbalas dgn asid
100Carbonate rock names:Micrite (microcrystalline limestone) - very fine-grained; may be light gray or tan to nearly black in color. Made of lime mud, which is also called calcilutite.Oolitic limestone (look for the sand-sized oolites)Fossiliferous limestone (look for various types of fossils in a limestone matrix)Coquina (fossil hash cemented together; may resemble granola)Chalk (made of microscopic planktonic organisms such as coccolithophores; fizzes readily in acid)Crystalline limestoneTravertine (see evaporites)Others - intraclastic limestone, pelleted limestone
103Siliceous rocks - The siliceous rocks are those which are dominated by silica (SiO2). They commonly form from silica-secreting organisms such as diatoms, radiolarians, or some types of sponges. Chert is formed through chemical reactions of silica in solution replacing limestones.Diatomite - looks like chalk, but does not fizz in acid. Made of microscopic planktonic organisms called diatoms. May also resemble kaolinite, but is much lower in density and more porous). Also referred to as Diatomaceous Earth.Chert - Massive and hard, microcrystalline quartz. May be dark or light in color. Often replaces limestone. Does not fizz in acid.
104. Organic Sedimentary Rocks (Coals) This group consists of rocks composed of organic matter (mainly plant fragments). Because of this, they lack minerals (which must be inorganic, be definition). These are the coals. In order of increasing depth of burial (temperature and pressure):Peat (porous mass of brownish plant fragments resembling peat moss)Lignite (crumbly and black)Bituminous coal (dull to shiny and black; sooty; layers may be visible)Anthracite coal (extremely shiny and black, may have a slight golden shine; low density; not sooty; technically a metamorphic rock due to high temperatures and pressures to which it has been subjected)
105othersThere are several other interesting sedimentary rock types: Ironstones - Oolitic hematite, banded iron formations
107SoalanMaklumat apakah yang boleh dicerap dari pemerhatian batuan mendak?Senaraikan…
108Sedimentary Structures Sedimentary structures form in the basin of deposition, as a result of the action of natural processes such as waves, currents, drying events, etc.Beds or strataCross-beddingGraded bedsRipple marks -Current ripple marks (asymmetrical ripples) Oscillation or wave ripple marks (symmetrical ripples)Mud cracks
109Structures formed during deposition 1-4, after deposition 5,6 23456
143www.webelements.com 14 Si 28.0855(3)The essentials Name: silicon Symbol: SiAtomic number: 14Atomic weight: (3) rCAS Registry ID:Group number: 14Group name: (none)Period number: 3Block: p-blockDescription Here is a brief description of silicon.Standard state: solid at 298 KColour: dark grey with a bluish tingeClassification: Semi-metallic
144Silicon is present in the sun and stars and is a principal component of a class of meteorites known as aerolites. Silicon makes up 25.7% of the earth's crust by weight, and is the second most abundant element, exceeded only by oxygen. It is found largely as silicon oxides such as sand (silica), quartz, rock crystal, amethyst, agate, flint, jasper and opal. Silicon is found also in minerals such as asbestos, feldspar, clay and mica.Silicon is important in plant and animal life. Diatoms in both fresh and salt water extract silica from the water to use as a component of their cell walls. Silicon is an important ingredient in steel. Silicon carbide is one of the most important abrasives. Workers in environments where silicaceous dust is breathed may develop a serious lung disease known as silicosis.
145Important factsHydrolysis and condensation of substituted chlorosilanes can be used to produce a very great number of polymeric products, or silicones. These range from liquids to hard, glasslike solids with many useful properties.Elemental silicon transmits more than 95% of all wavelengths of infrared and and has been used in lasers to produce coherent light at 456 nm.
146IsolationHere is a brief summary of the isolation of silicon.There is normally no need to make silicon in the laboratory as it is readily available commercially. Silicon is readily available through the treatment of silica, SiO2, with pure graphite (as coke) in an electric furnace.SiO2 + 2C Si + 2COUnder these conditions, silicon carbide, SiC, can form. However, provided the amount of SiO2 is kept high, silicon carbide may be eliminated.2SiC + SiO2 3Si + 2COVery pure silicon can be made by the reaction of SiCl4 with hydrogen, followed by zone refining of the resultant silicon.SiCl4 + 2H2 Si + 4HCl
148Most cities and large towns in the Peninsula are located on a thin surface alluvium over limestone and granite.
149Malaysia is generally formed by highland, floodplain, and coastal zones (Figure 1.2 ). In the Peninsula, the Banjaran Titiwangsa from north to south divides the West Coast and East Coast states, while in Sarawak the Banjaran Kapuas Hula and Banjaran Iran border Indonesia. All of these ranges are governed by virgin forest
150Malaysia is warm and humid throughout the year, as characterised by the equatorial climate, and has an average annual rainfall of more than 2500 mm with spatial variation shown in Figure
151In the Peninsula wettest area is Taiping in Perak whilst the driest is Kuala Pilah in Negeri Sembilan (Figure ). Average daily temperatures range from a minimum of 25o C to a maximum of 33o C. Relative humidity is high, sometimes exceeding 80%. Daytime cloudy hours are also high while haze lately is a frequent occurrence that will contribute to acid rains.
152Urbanisation poles are formed in many different ways including; · centrally in dense arrangements such as towns, cities, ports, commercial/business centres, and new development areas· linearly along road, highway, railway, river, estuary, and coastal areas· randomly located, including villages and high class residential areas