ROCKS CYCLE , TYPES OF ROCKS AND ECHETERA

Its all about how rock created

1. rocks

2. Learning objectives Classify rocks into igneous, sedimentary and metamorphic rocks

3. ROCKS Rocks are natural solid materials that make up the lost of the Earth’s lithosphere. Rocks that form a bigger mass are composed of tiny particles of minerals compressed together due to pressure and temperature. There are three (3) types of rocks which can interchangeably transform form one type to another. Igneous Rocks, Sedimentary Rocks, and Metamorphic Rocks.

4. MAGMA – Molten material found beneath the surface of the Earth Cools down and solidifies IGNEOUS ROCKS – may either occur on the surface or beneath the ground EXTRUSIVE OR VOLCANIC IGNEOUS ROCKS- formed on the surface INTRUSIVE OR PLUTONIC IGNEOUS ROCKS – formed beneath the ground Surface of the Earth – Igneous Rocks are slowly broken down into smaller fragments through the process of WEATHERING. SEDIMENTS Different agents of erosion will transport down to nearby bodies of water/deserts In the spite of DEPOSITION, sediments undergo processes SEDIMENTATION, COMPACTION & CEMENTATION Some rocks remain on the surface of the Earth Some rocks are buried and will be subjected to great pressure and intense heat METAMORPHIC ROCKS SEDIMENTARY ROCKS Further heating and exposure to extreme pressure and temperature

5. Igneous rocks Formed from solidification of lava when a volcano erupts. 2 BASIC TYPES Intrusive or Plutonic Igneous Rocks- Granite, Diorite, Gabbro, Pegmatite, Dunite , Periodite Extrusive or Volcanic Igneous Rocks- Basalt, Andesite, Obsidian, Pumice, Rhyolite, Scoria and Tuff.

6. INTRUSIVE OR PLUTONIC IGNEOUS ROCKS – formed beneath the ground EXTRUSIVE OR VOLCANIC IGNEOUS ROCKS- formed on the surface

7. IGNEOUS ROCKS CAN BE CLASSIFIED ACCORDING TO: Mode of occurrence Texture Mineralogy Chemical composition Geometry

8. TEXTURE Describes the physical appearance of the rock based on the size and arrangement of its crystal components. Igneous rocks can be classified as follows: Fine-grained igneous rocks – consist of large crystals and likely formed far below the surface of the Earth Coarse-grained igneous rocks – consist of large crystals and likely formed far below the surface of the Earth Porphyritic igneous rocks – consist of large crystals embedded on a group of smaller crystals Glassy igneous rocks- formed when a molten rock is ejected by a volcano into the atmosphere causing the lava to cool instantly.

9. SEDIMENTARY ROCKS Formed by the accumulation of sediments. 3 BASIC TYPES CLASTIC SEDIMENTARY ROCKS CHEMICAL SEDIMENTARY ROCKS ORGANIC SEDIMENTARY ROCKS

10. CLASTIC SEDIMENTARY ROCKS Composed of clasts which are little pieces of broken rock particles that have been joined together as a result of COMPACTION and CEMENTATION. Examples: Breccia, conglomerate, sandstone, siltstone, shale are product of mechanical weathering.

11. CHEMICAL SEDIMENTARY ROCKS Formed as a result of repeated flooding and evaporation. When water evaporates, it leaves a layer of dissolved minerals behind like; Rock salt, iron ore, chert, flint, some dolomites, and some limestones.

12. Organic sedimentary rocks Formed from the accumulation of plant and animal debris. Examples; coal, some dolomites, and some limestones.

13. Metamorphic rocks Have been modified by heat, pressure and chemical processes usually while buried deep below the Earth’s surface. Can be FOLIATED or NONFOLIATED FOLIATED METAMORPHIC ROCKS – have layered or banded appearance caused by exposure of minerals to heat and pressure. Examples: Gneiss, Phyllite, Schist, Slate NONFOLIATED METAMORPHIC ROCKS- do not display layering or banding that are present in foliated rocks. Examples: Hornfels, Marble, Quartzile , Novaculite

14. WHAT FACTORS CAUSE THE DIFFERENT SHAPES AND STRUCTURES OF THE EARTH? EXOGENIC PROCESSES- caused by exogenic factors or agents supplying energy for activities that are located at or near the Earth’s surface. Processes that are caused by exogenic factors are; Weathering - 2 TYPES : physical weathering and chemical weathering Erosion Mass wasting Denudation

15. weathering Process of degradation or breaking down of rocks into smaller fragments known as SEDIMENTS. It occurs when mechanical force is applied on rocks or through chemical reactions happening on the surface or within the rocks. PHYSICAL WEATHERING- also called mechanical weathering and it is caused by the breaking apart of rocks without changing their chemical composition. The following are examples that illustrate physical weathering. FROST HEAVING AND WEDGING- this occurs when water seeps into the rocks or occupies spaces in between rocks and freezes, acting like a wedge. PLANT ROOTS- Huge trees that produce large roots anchor themselves on rocks and force their way into them.

16. BURROWING ANIMALS - Some animals create their home by making holes on the rocks. ABRASION – Rocks in the rivers, seas, valleys, mountains, deserts, degrade or disintegrate due to friction or repeated collisions or impacts. TEMPERATURE CHANGES- Sudden changes in temperature weaken the integral structure of rocks, resulting to weathering.

17. Chemical weathering Involves the chemical decomposition or rocks due to the chemical reaction of minerals within rocks and the environment, Some agents of chemical weathering are as follows; WATER – It dissolves the soluble minerals present in rocks. OXYGEN- It facilitates the oxidation process in the presence of water in some metallic minerals, such as PYRITE. LIVING ORGANISMS- Organisms, such as lichens, produce weak acids that slowly corrode the rocks. ACIDS- Carbon Acid is formed when carbon dioxide present in the atmosphere reacts with water. It easily decomposes LIMESTONES and MARBLES. Acid rain is formed from nonmetallic oxides. These oxides are formed from the burning of coal and natural activities that react with rain water to form acids in the atmosphere.

18. Erosion and mass wasting EROSION happens when fragments of rocks move form place to another. MASS WASTING is the movement of large fragment of rocks down the slope due to gravity. Landslides., mudslide, slumps, and debris flow are all examples of mass wasting.

19. 2. ENDOGENIC PROCESSES- are caused by endogenic factors, or agents supplying energy for activities that are located within the Earth or below the Earth’s surface. They refer to the movement of the Earth’s lithosphere resulting to formation of various landforms. MAGMATISM- explains the movement of magma to form igneous rocks. This is the process reasonable also for mountain formation. PLUTONISM- also known as VOLCANISM, explains that the rocks are formed in fire by volcanic activity.

20. What causes the deformation of the earth’s crust? 1. PLATE TECTONICS- formulated during the 1960s This Plate Tectonic Theory explains that the lithosphere was so brittle that it was divided into major plates considered to be floating over the hot liquid of asthenosphere. 7 MAJOR PLATES North American - African - Antartic South American - Eurasian Pacific - Australian

21. 6 MINOR PLATES Cocos - Scotia Caribbean - Arabian Nazca - Philippine

22. CONTINENTAL DRIFT THEORY- ALFRED WEGENER created a map of the Earth by fitting the continents into one. He then hypothesized that the continents were joined together into one supercontinent known as PANGAEA about 225 million years ago. Since then, as explained in the plate tectonic theory, the continents were constantly moving that resulted to the splitting of the supercontinent into two major continents GONDWANALAND LAURASIA

23. Wegener’s Theory required evidence to support the claim. Aside form the fact that the continents look like a jigsaw puzzle, other evidences were gathered. Fossils of a dinosaur known as the MESOSAURUS that had been found in South America and Africa, but nowhere else in the world. Fossils found in Antartica , Africa, Australia, South America and India supported the claim of Wegener. These were fossils of a fern called GLOSSOPTERIS.

24. The continental drift may be proven by evidence, but what is causing the movement? According to geologists, the movement of the plates can be attributed to 3 possible forces, and one of them is GRAVITY- the most common force that shapes the surface of the Earth. The plates are made up of denser materials than the asthenosphere, allowing them to be pulled by gravity and making them sink and gradually move across each plate. Another possible cause is CONVECTION CURRENT that exists within the asthenosphere. Geologist explain that the materials within the asthenosphere circulate due to differences in temperature. Hotter materials go up to the Crust, while colder materials are pushed to the center of the Earth, moving in a circular pattern. As the materials move, they slightly push the plates above, causing the plates to move. The 3 rd possible cause is the THERMAL PLUME or known as the MANTLE PLUME. Thermal Plumes are vertical columns of molten materials that rise up from the mantle towards the bottom of the lithosphere and spread out beneath the plates, causing the plates to move.

25. SEAFLOOR SPREADING MID-ATLANTIC RIDGE Part of a continuous submarine mountain chain called the MID-OCEANIC RIDGE which girdles the entire globe LATERAL MOTION OF CONTINENTS YOUNG AGE OF OCEANIC CRUST confirms indicates SEAFLOOR SPREADING AND PLATE TECTONICS THEORIES- 1960s (Seafloor Spreading Hypothesis which states that the oceanic crust is created as the seafloor spreads apart along mid-ocean ridges) ROBERT S. DIETZ & HARRY H. HASS (Prepared detailed maps of the ocean floors and the mid-Atlantic ridge and rift system that seemed to support the Continental Drift Theory) BRICE C. HEEZEN, MARIE THARP & OTHERS (Paleomagnetism- record of the orientation of Earth’s magnetic field recorded in rocks) S. KEITH RUNCORN. (Vine Matthews Hypothesis- record of changes in the Earth’s magnetic field when magnetic stripes were discovered formed at spreading centers of the mid-ocean ridges) FRED J. VINE & DRUMMOND MATTHEWS (Magnetic Stripes- indicated reversals of the direction of the Earth’s magnetic field recorded in rock as new ocean crusts were created at mid-ocean ridges) LAWRENCE MOLEY/confirmed by WALTER PITMAN

26. ISOSTASY Refers to the state of gravitational equilibrium between the Erath’s lithosphere and asthenosphere such that the tectonic plates float at an elevation, which depends on their thickness and density. It explains how different topographic heights can exist at the Earth’s surface. When a certain area of lithosphere reaches the state of isostasy, it is said to be in isostasic equilibrium. Isostasy can be observed where the Earth’s strong lithosphere experts stress on the weaker asthenosphere over geological time. It flows laterally such that the load of the lithosphere is accommodated by height adjustments.

27. Plate boundaries 3 TYPES OF PLATE BOUNDARIES Transform fault boundary occurs when two plates slide or grind past each other. Divergent boundary occurs when 2 plates move away from each other. The divergence of two continental plates creates a rift variety. Convergent boundary occurs when 2 plates come together or move towards each other. The convergence of 2 oceanic plates creates island arcs and trenches. *** THE CONVERGENCE OF AN OCEANIC PLATE AND A CONTINENTAL PLATE RESULTS IN THE FORMATION OF VOLCANIC MOUNTAIN REANGE AND TRENCHES. THE CONVERGENCE OF 2 CONTINENTAL PLATES CREATES FOLDED MOUNTAIN RANGE.

28. folds and faults FOLDS are bent rock layer or series of layers that are originally horizontal and subsequently deformed. 2 MOST COMMON TYPES ANTICLINE- fold in the sedimentary strata resembling an arc. SYNCLINE- linear downfold in the sedimentary strata *** synclines and anticlines very in symmetry.

29. FAULTS are fractures in the crust along which appreciable displacement has occurred on a scale from centimeters to kilometers. Graben- a valley formed by downward displacement of the fault-bounded block. Horst- is an elongated, uplifted block of crust bounded by faults. 4 TYPES OF FAULTS Normal Fault Reverse Fault Trust Fault Strike-slip Fault

30. NORMAL FAULT – a dip slip fault in which the rock above the fault plane has moved relative to the rock below. REVERSE FAULT- a dip slip fault in which the material above the fault plane moves up in relation to the material below.

31. THRUST FAULT – a reverse fault with dip less than 45 degrees. STRIKE-SLIP FAULT- a fault on which the movement is horizontal.

32. How did the earth evolve? 1. PRECAMBRIAN TIME AS THE SUN IS FORMED, THE SOLAR SYSTEM STARTED TO CONSTRUCT. THE FORMATION OF THE SOLAR SYSTEM GAVE BIRTH TO THE PLANET EARTH. IT WAS 4.6 BIL;LION YEARS AGO, AS ELEMENTS COMBINED TO FORM THE PLANETS. THE EARTH’S 4.6 BILLION –YEAR HISTORY IS SUBDIVIDED INTO 4 MAJOR UNITS OF TIME. PRECAMBRIAN TIME- earliest of the Earth’s history.

33. 2. PALEOZOIC ERA major interval of geologic time that began 541 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history. However, the amphibians could only reside near water for them to deposit their eggs. Later they developed the ability of producing shells allowing them to carry their eggs anywhere on land. Reptiles and insects emerged.

34. 2. MESOZOIC ERA Also known as the age of the dinosaurs. This was the time when gymnosperms emerged and the land was dominated by reptiles. Mammals started to evolve too, but were held back by the dinosaurs. The supercontinent Pangaea began to separate, forming the rocky mountains.

35. 2. CENOZOIC ERA The Cenozoic is Earth's current geological era, representing the last 66 million years of Earth's history. It is characterized by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configuration of continents.