UNIT 2: ROCKS, SOIL & MASS MOVEMENTS

A concept map is a diagram showing the relationships among concepts. ▫graphical tool for organizing and representing knowledge ▫Concepts are represented as boxes or circles ▫Connected with labeled arrows in a branching structure. CONCEPT MAPPING

CONCEPT MAP #1: Forces & Motion Igneous, sedimentary, and metamorphic rocks are interconnected by a set of processes called the rock cycle. A common path through the rock cycle is for igneous rock to be weathered, transported and deposited to eventually become sedimentary rock. Then this sedimentary rock is subjected to high temperatures & pressures that turn it into metamorphic rock. Eventually the metamorphic rock becomes new igneous rock.

CONCEPT MAP #2: Matter & Energy There are many factors that affect the appearance of a rock. For igneous rocks, these factors include the composition and the rate of cooling. For sedimentary rocks, these include the types of sediment compacted (clastic, chemical, biological). For metamorphic rocks, these include the amounts of heat, pressure, and hot fluids the rocks are exposed to.

What do you already know? What is a rock? What are the three major types of rocks? What energy processes destroy and make new rocks?

Mineral Naturally occurring inorganic solid with a definite crystalline structure and specific chemical composition

Rock Naturally occurring solid made of one or more minerals Rocks are classified based on the way they form.

Three Major Types of Rocks 1.IGNEOUS = formed when liquid magma cools and hardens ▫From the Latin ignis meaning born of fire

2.SEDIMENATRY = formed from the sediments of other rocks already present or very near earth’s surface Three Major Types of Rocks

3.METAMORPHIC = formed under high pressure and heat for long periods of time  The heat and pressure cause the rock to change into new rock.  Metamorphosism = change of form Three Major Types of Rocks

SEDIMENTARY ROCK METAMORPHIC ROCK IGNEOUS ROCK HEAT & PRESSURE SEDIMENT MAGMA MELT ERODE & WEATHER COMPACTION & CEMENTATION ERODE & WEATHER ERODE & WEATHER MELT HEAT & PRESSURE COOL & HARDEN THE ROCK CYCLE

IGNEOUS ROCK Always begins as magma deep in the earth. The magma cools and hardens into crystals deep in the earth or nearer to the surface. Classified by where they form, texture, and composition

Two Types of Igneous Rock 1.Intrusive = formed deep within the Earth Examples: batholith, dike, sill, stock, laccolith

2.Extrusive = formed from lava at Earth’s Surface ▫Examples: volcanic rock, pumice, obsidian Two Types of Igneous Rock

Igneous Texture Depends on the size of the crystals Slower cooling = larger crystals ▫Intrusive rocks cool more slowly, creating larger crystals. ▫Called “coarse-grained” ▫Example: granite

Igneous Texture Faster cooling = smaller crystals ▫Extrusive rocks cool more quickly, creating smaller or no crystals ▫Called “fine-grained” ▫No crystals = glassy or amorphous ▫Examples: basalt, obsidian QUESTION: WHICH IS MORE DENSE- BASALT OR GRANITE? BASALT IS MORE DENSE the ocean floor is made of it while the continental crust is made mostly of Granite which is LESS DENSE! The Land will “float” on the ocean floor at subduction zones!

Igneous Texture Porphyritic Texture: when magma cools and harden under Earth’s surface, it can cool at different rates, causing varying crystal sizes. The result is called porphyritic. Larger crystals can even form on smaller crystals

Igneous Textures COARSE-GRAINEDFINE-GRAINEDGLASSY PORPHYRITIC

Composition What is it made of? What color is it? Six mineral combinations: Quartz Feldspar Pyroxene Amphibole Olivine Mica The combinations of the minerals determine the color of the rock. Types of Marble

Examples of Igneous Rocks 1. Granite 2. Rhyolite 3. Gabbro 4. Basalt 5. Obsidian 6. Pumice

Metamorphic Rock Metamorphosis means change ▫So, metamorphic rock is changed ingenous or sedimentary rock

Agents of Metamorphism Heat: changed occur between 100 o C and C Pressure: Extreme pressures 12-16km below Earth’s surface can change the crystalline structure, altering the type of rock Reaction to solutions (ex: hydrothermal vents)

Types of Metamorphism 1.Contact Metamorphism=rocks are heated through direct contact with magma or lava. 2.Regional Metamorphism=occurs over a large area. a.Is the most common type of metamorphism b.Widespread and intense heat and pressure deep in the earth cause changes in the rock. WHAT TYPE OF METAMORPHISM IS THIS EXAMPLE?

Classification of Metamorphic Rock 1.Foliated: Crystals are arranged in bands or layers a.Cleavage occurs along these bands 2.Unfoliated: do not have bands of crystals a.Do not cleave in layers b.Most contain 1 mineral (ex: marble is nonfoliated rock made of calcite)

Examples of Metamorphic Rock Parent rock- original rock before metamorphism takes place 1.Slate (Shale) 2.Gneiss (Schist, granite) 3.Marble (Limestone) 4.Quartzite (Sandstone) 5.Schist (Phyllite) 6.Anthracite (Bituminous coal)

Sedimentary Rock Sediments: form from the breakdown of igneous, sedimentary, or metamorphic rocks at Earth’s surface ▫Deposited in layers, and are compacted & cemented forming new rock. ▫Can be reformed into igneous rock by subduction at deeps-sea trenches (returned to the interior of the earth)

Examples of Sedimentary Rocks CLASTIC ROCKS CONGLOMERATEBRECCIASANDSTONESHALESILTSTONE Gravel size particles Angular particles Sand sized particles Very fineVery very fine

Examples of Sedimentary Rocks CHEMICALBIOCHEMICAL Limestone & GypsumCoquina & Chalk Precipitate from solutionShells and skeletons of marine organisms cemented together

Sedimentary Rock 75% of all rocks on Earth’s surface are sedimentary Mainly made of mud, sand, and gravel Moved by wind and water. Faster wind or water can carry larger particles.

Sedimentary Rocks Over millions of years mud, sand, grave, bones, and shells settle to the sea floor as sediments. They pile up in layers of meters thick. White Cliffs of Dover, England

Sedimentary Rocks As sediments pile up, the pressure becomes greater. ▫What happens to the sediments?  The pressure squeezes the sediment together, hardening it into rock. Results in rock layers or strata. This is the major characteristic of sedimentary rocks!

Features of Sedimentary Rock 1.Strata= layering of the rock when there is a change in the type of sediments deposited 2.Ripple Marks 3.Mud Cracks 4.Fossils= remains of animals and plants preserved in the rock.

Examples of Sedimentary Rock Conglomerate Breccia Sandstone Limestone Rock salt

IGNEOUSMETAMORPHICSEDIMENTARY How it’s formed: Examples: How does it change into other rock types? Explain thoroughly!! Becoming Metamorphic: Becoming Sedimentary: Becoming Igneous: Becoming Sedimentary: Becoming Igneous: Becoming Metamorphic: At least 2 other facts:   