Geology The rock cycle Earth materials and their stories Experiments in the lab and working with rock kits (in school) Plate Tectonics The Dynamic Earth The story of fossils The Geological History of the Arava Valley, and its margins The Geology of the Arava in the view of the Rock Cycle Geology and man in the Arava Valley ד"ר חנן גינת ד"ר ירון פינצי
The rock cycle In the view of EARTH MATERIALS
The rock cycle in the view of the rock groups
Some definitions: Minerals - The building blocks of rocks. Rocks are made of minerals; the minerals can be colored and made of different ingredients Rock - A naturally occurring aggregate of minerals or: Any mass of mineral matter which forms part of the Earth s crust. Rock may consist of only one mineral species (mono-mineral rock) or be an aggregate of mineral species. Rock Cycle - A cycle that shows how rocks are formed and the processes in the earth crust and above.
atom particles atoms molecules Minerals rocks Earth Materials Hierarchy
For rocks identification we use: - color - hardness - fizz with acid? - malleability - structure - special characteristics
Igneous Materials (rocks and minerals) Igneous Processes Igneous structures and phenomena
Some interesting questions: Write five questions about magmatic rocks and processes
Some interesting questions: 1.Why are there so many different kinds of igneous rocks? 2. What is a magma chamber? 3. What is a cold environment and a hot environment? 4. What is the difference between eruption and expulsion? 5. What is the engine that gives the power to the volcanic processes. 6. What is the right place of the igneous rocks in the rock cycle? 7. Are there really 70,000 km. of volcanic mountain in the deep oceans? (Igneous = magmatic)
Contents 1. The igneous rocks characteristic and the story behind them. 2. Simple experiment to demonstrate volcanic processes. 3. Identification of magmatic phenomena and their evolution 4. Virtual field trip in volcano environment (and mountains)
The red rocks rhyolite granite rhyolite porphir
The gray rocks (the intermediate rocks) andesite diorite Porphiritic andesit pumice
The black rocks gabbro basalt obsidian
Color/ Crystal size red gray black Fine grained (volcanic) Coarse grained (plutonic) porphir
The main reasons for the high variety of the igneous rocks are: 1. The crystal size Salol that crystallize above cold glass Observations: - small crystals - fast crystallization Salol that crystallize above hot glass Observations: - big crystals - slow crystallization Conclusions: Volcanic rocks Plutonic rocks 1. Igneous rocks with coarse crystals crystallize slowly in a hot environment 2. Igneous rocks with fine crystals crystallize fast in a cold environment
Demonstration of magmatic processes The water The Surface The sand The environment rock The heater The heating origin
What are these hot and cold environments? 1. Is it in different latitude (for example in Antarctica and Sahara Desert)? 2. Is it under the sea and above continent? 3. Or.???? Climate map
2. The origin of the magma and its composition
3. Different magmatic processes (definitions and pictures) explosion Injection intrusion eruption A. A blowing apart with force B. The act or process of moving out C. The act or process of pushing under the surface D. A liquid passed through a needle or small opening
Geological quiz Find the right name of the phenomena and the necessary conditions that permit it. Columnar Basalt - Magma fast cooling - Weathering processes along the cracks
Ropy basalt - Very rubble lava
Dykes - Joints in the deep crust - vertical or horizontal injection of magma - weathering and exposure of the dykes
Travertine white sediments of hot water - Presence of groundwater - Presence of heat (as hot magma) - Presence of joints, that the hot water can come through
Mt. Etna, Sicilia, Italy http://www.sicilian.net/etna2002/
Stages of the development of a volcano You have to sort them to the right stages and to write the what happened in each stage
Mount St. Helen, USA 15.5.1980 6.10.2004 http://vulcan.wr.usgs.gov/volcanoes/msh/
New Zealand volcano
Some more pictures and figures
להמשך המצגת
המשך
Why are there so many kinds of magmatic rocks?
The global aspects The Earth Dynamic map mountains, subduction areas and the ocean ridges
Rings of fire
Volcanism along the east part of Ethiopia The Blue Nile Afar Valley
בזלות צעירות מאוד עדויות לזרימה
מלכודות אוויר וסדקים בבזלות הצעירות
Metamorphic rocks and processes New rock textures and new mineral assemblages develop when rocks are subjected to elevated temperatures and pressures. Changes that take place while the rock is still solid are called metamorphism. Metamorphic changes start at about 150 o C (equivalent to a depth within the Earth of 5 km) and cease around 800 o C where the rocks start to melt. The Pietà, Michaelangelo's most famous statue, was carved from marble, a metamorphic rock from the Carrara quarries in Italy.
What are the three types of metamorphism? The processes that cause changes in texture and in mineral assemblage in metamorphic rocks are mechanical deformation and chemical recrystalization.
The origin rocks Metamorphosed rocks Granite Gneiss Limestone Marble
Clay Schist Sandstone Quartzite
And Some times with new metamorphic minerals Schist Garnet Tourmaline Mica Schist Pore fluids allow dissolved minerals to be transported and reprecipitated elsewhere; they also speed up chemical reactions. FoliationThe schist
The composition of metamorphic rock is strongly controlled by the composition of the parent rock, but other factors also apply. The growth of new mineral phases during metamorphism is primarily controlled by temperature. High temperatures, pressures and abundant pore fluids result in metamorphic rocks with large mineral grains The original structure Elongated structure after metamorphism
The changes that occur during metamorphism often produce a texture called foliation. This is caused by the preferential orientation of newly-formed micaceous minerals Foliation in low-grade metamorphic rocks is called slaty cleavage. Both foliation and cleavage develop perpendicular to the direction of maximum stress
The diagram shows the conditions of pressure and temperature in which diagenesis, metamorphism, and melting occur in the Earth's crust. Metamorphic changes start at about 150 o C (equivalent to a depth within the Earth of 5 km) and cease around 800 o C where the rocks start to melt
How do solid rocks change? As temperature and stress increase on a sedimentary rock, like shale, different mineral assemblages are formed, ultimately resulting in the metamorphic rocks slate, phyllite, schist, and gneiss.
What are the metamorphic facies? For a given rock composition, the assemblages of minerals that are formed under a specific temperature and pressure are always the same. This fact allows us to define specific metamorphic facies.
Sedimentary rocks that are saturated with water and subjected to elevated temperatures and pressures undergo burial metamorphism. Regional metamorphism occurs under differential stress and elevated temperatures as a result of the collision of tectonic plates. Regionally metamorphosed rocks commonly extend over areas of thousands of square kilometers
Subduction Zone
Paired metamorphic facies are common in subduction zone tectonic environments. Ocean floor basalts exposed to variable pressures and temperatures form well-foliated greenschists and amphibolites, or weakly-foliated blueschists and eclogites.
The rock cycle In the view of EARTH MATERIALS
The diagram shows the conditions of pressure and temperature in which diagenesis, metamorphism, and melting occur in the Earth's crust. Metamorphism New rock textures and new mineral assemblages develop when rocks are subjected to elevated temperatures and pressures. Changes that take place while the rock is still solid are called metamorphism
The rock cycle through the view of internal and external PROCESSES