COLOR CODE THE PATHWAY TO IGNEOUS ROCKS! A R O U N D W E G O
VOCABULARY FOR IGNEOUS ROCKS IGNEOUS ORIGINS volcanoes active volcano dormant volcano magma plutonic rocks intrusives lava volcanic rocks extrusives IGNEOUS TEXTURE interlocking crystals very coarse coarse fine glassy texture vesicular texture porphyry pegmatite IGNEOUS COMPOSITION felsic minerals mafic minerals
WHAT IS A VOLCANO? THE SOURCE OF IGNEOUS ROCKS!
WHERE ARE THE ACTIVE VOLCANOES LOCATED TODAY? VOLCANOES!
ACTIVE, DORMANT, OR EXTINCT VOLCANOES What s the difference? The timeframe depends on where the volcano is located Active recent activity such as eruptions or earthquakes or visible magma Dormant not showing recent activity Extinct unlikely to erupt again
WHERE are the World s Mountain Chains compared to VOLCANOES Brooks Range
EVIDENCE-BASED CONCLUSIONS MP#3 QUARTERLY ASSESSMENT 1. Using your own work - Describe at least three clear patterns of worldwide volcanic activity. Include: Introduction statement followed by three pattern statements. For each pattern, describe the pattern, use directions (N,S,E & W) to explain where it is located, and the geographic features (mountains, islands, oceans, seas, continents, etc..) associated with the pattern. Use specific volcano numbers as evidence. Be complete. 2. Draw a line to separate Part 1 from Part 2 on your sheet. Now use evidence from the volcano map provided to answer the same question. It has a lot more data and patterns may be easier to see. You can discuss the patterns with your partner before you write your answer.
NOTEBOOKS, please! Geographic Patterns and Earth s History 1. Evidence comes first (e.g., what s the pattern of volcanoes and geography today?) Observations (data) Complete details Unbiased as much as possible 2. Interpretations second! (e.g., why does that pattern of volcanoes and geography exist) Inferences Explanations based on data (evidence) These might be biased, so be critical!
LET S USE DETAILED OBSERVATIONS TO DESCRIBE THE PATTERNS OF VOLCANOES (AND EARTHQUAKES) USING GEOGRAPHY!
HOW does geography relate to VOLCANOES?
VOLCANOES
SEISMOLOGY (EARTHQUAKES)
Remember, the EVIDENCE LOCATIONS OF VOLCANOES AND EARTHQUAKES - CAME FIRST before plate boundaries could be drawn!
Some are located at plate boundaries
But some are not at plate boundaries FIND THE MANTLE HOT SPOTS!
WHY ARE THERE VOLCANOES AT DIFFERENT TYPES OF PLATE BOUNDARIES?
WHY ARE THERE VOLCANOES AT DIFFERENT TYPES OF PLATE BOUNDARIES? VOLCANOES are MOST FREQUENTLY FOUND at plate boundaries
WHY ARE THERE VOLCANOES AT DIFFERENT TYPES OF PLATE BOUNDARIES? VOLCANOES are SOMETIMES FOUND at plate boundaries
WHY ARE THERE VOLCANOES AT DIFFERENT TYPES OF PLATE BOUNDARIES? VOLCANOES are NOT USUALLY FOUND at plate boundaries
AN ERUPTING SHIELD VOLCANO USUALLY ISN T EXPLOSIVE AND IT LASTS A LONG TIME! HAWAII has flowing BASALT MAGMA from a magma chamber hot spot below the ocean floor
AN ERUPTING COMPOSITE VOLCANO LIKE MT. ST. HELENS EXPLODES VIOLENTLY BECAUSE OF STICKY LAVA PLUGS! DIFFERENT IGNEOUS ROCKS RESULT FROM DIFFERENT ENVIRONMENTAL Mt. St. Helens formed a PUMICE CALDERA at the surface from the explosive gases CONDITIONS
WHERE S THE STRATOSPHERE?
WHERE S THE BIGGEST RISK FROM EXPLOSIVE SUPERVOLCANOES IN NORTH AMERICA TODAY? YELLOWSTONE has sticky RHYOLITE MAGMA over denser BASALT MAGMA
WHEN WE FIND IGNEOUS ROCKS, WE USE THEIR PROPERTIES TO INFER WHAT ENVIRONMENT THEY FORMED IN. IN PLACES WHERE NO VOLCANOES EXIST TODAY, WE CAN INTERPRET THAT TO MEAN THAT THERE ONCE WAS VOLCANIC ACTIVITY THERE! WE INTERPRET EARTH S DYNAMIC HISTORY FROM THE STORY THAT IS WRITTEN IN THE ROCKS!
VOCABULARY FOR IGNEOUS ROCKS IGNEOUS ORIGINS volcanoes active volcano dormant volcano magma plutonic rocks intrusives lava volcanic rocks extrusives IGNEOUS TEXTURE interlocking crystals very coarse coarse fine glassy texture vesicular texture porphyry pegmatite IGNEOUS COMPOSITION felsic minerals mafic minerals
Explosive gases and ejecta Explosive cool gases quicklyand ejecta ABOVE GROUND IGN ROCKS Fine crystals No crystals (glassy) Vesicular or non-vesicular GENERALIZED STRUCTURE of a VOLCANO WHERE MAGMA PLUTONICS & VOLCANICS GOES and COOLS Molten lava flow above ground cools quickly Or conduit Molten lava flows into water and cools really fast BELOW GROUND IGN ROCKS Coarse to very coarse crystals Non-vesicular MOLTEN MAGMA CHAMBER underground where it cools slowly
JUST READ the ROWS to see where igneous rocks formed and the COLUMNS to see what they are made of!
Explosive gases and ejecta PLUTONICS & VOLCANICS TWO TYPES OF IGNEOUS ROCKS DEPENDING ON WHERE Molten Lava MAGMA Flow COOLED!!!! http://geologyonline.museum.state.il.us/tools/lessons/12.1/lesson.html
Explosive gases and ejecta PLUTONICS & VOLCANICS Molten Lava Flow PLUTONIC ROCKS INTRUSIVE ROCKS cool SLOWLY below ground and have coarse or very coarsecrystals http://geologyonline.museum.state.il.us/tools/lessons/12.1/lesson.html
Explosive gases and ejecta PLUTONICS & VOLCANICS EXTRUSIVE ROCKS cool QUICKLY above Molten Lava Flow ground and have fine or no crystals and can have air bubbles (vescicular) VOLCANIC ROCKS http://geologyonline.museum.state.il.us/tools/lessons/12.1/lesson.html
For environment, JUST READ the ROWS!
TEXTURE results from the environment where the rock formed
IGNEOUS ROCKS VOLCANICS COOLING TIME CRYSTAL SIZES and ENVRONMENT of FORMATION GAS POCKETS LIKELY?
IGNEOUS ROCKS PLUTONICS COOLING TIME CRYSTAL SIZES and ENVRONMENT of FORMATION GAS POCKETS
Now, read the COLUMNS! MINERAL COMPOSITION of igneous rocks depends on the type of magma it came from!
ESTIMATING PERCENTS of each MINERAL
LET s IDENTIFY some IGNEOUS ROCKS
It s LAB TIME!!! Lab 18 Igneous Rock ID