properties of Igneous Rocks - research the 3 rock specimens below. These specimens are examples of three varieties of igneous rocks: scoria, basalt, and gabbro. In certain ways these three rocks are an extremely similar: they space all dark gray and are written of essentially identical chemical components. This shows that the basalt and also the gabbro space made the the exact same minerals. The scoria is fine-grained or glassy and therefore contains no clearly shows minerals. Once minerals room present, they space the same ones as found in the basalt and also gabbro. In other methods the specimens are different. Using the table below, briefly define how these three rocks differ from each other.

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SCORIA

BASALT

GABBRO

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How do the differences listed above in grain size and also the existence of wait pockets arise?
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Only two of this rock species are discovered in sills. Which space they and where space they located within the sill? Why?
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All 3 rock types may be found within the lava flow. Wherein would castle be situated within the flow? Why?
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In the Andes Mountains, huge bodies that magma (molten rock) were intruded upward right into older rocks and also solidified to kind formations referred to as batholiths do of igneous rocks (see the figure below). In part places, the magma was required into cracks and solidified to form cross-cutting bodies made the igneous rocks called dikes. Few of the cracks prolong to the surface of the earth and also molten absent made its means upward and was erupted in ~ the surface as lava flows which solidified to form igneous rocks.
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Examine the adhering to specimens: pumice, obsidian, rhyolite, granite, and pegmatite. All these rocks room chemically similar. The pumice and obsidian room glasses and contain no minerals. The rhyolite, granite, and also pegmatite contain mineral which space the very same or similar.

PUMICE

OBSIDIAN

RHYOLITE

GRANITE

PEGMATITE

How do the pumice and obsidian different from each other?
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How carry out the rhyolite, granite and also pegmatite different from each other in terms of grain size?
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How walk the differences in between these 5 specimens originate?
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PUMICE - cooled down an extremely fast from lava and also has vesicles that suggest that gases to be escaping from the rock - microscopic crystals.

OBSIDIAN - also cooled down very fast indigenous lava and that is why the glassy appearance v no crystals.

RHYOLITE - is a mixture the crystals the were cooling down progressively inside the magma chamber and also then a volcano explosion lugged them as much as the surface embedded in a soil mass the cooled really quickly.

GRANITE - cooled gradually inside the magma chamber fairly closer to the surface - tool size crystals.

PEGMATITE - cooled in ~ depth within the magma room - huge crystals.


Igneous rocks are split into 2 groups: volcanic (extrusive) and PLUTONIC (intrusive).
VOLCANIC or EXTRUSIVE igneous rocks come from solidified LAVA. Because LAVA COOLS quickly (outside the Earth"s surface) crystals (grains) execute not have actually time to grow, as such volcanic or extrusive igneous rocks have actually tiny, sometimes microscopic crystals, or castle don"t have actually crystals at all.

PLUTONIC or EXTRUSIVE igneous rocks come from solidified MAGMA. Due to the fact that MAGMA COOLS slowly (inside the Earth"s surface) crystals (grains) have time to grow, therefore plutonic or intrusive igneous rocks have actually medium size to large crystals.


In addition igneous rocks according to thier chemical composition room subdivided in to two main groups: MAFIC and also FELSIC.
MAFIC igneous rocks room DARK in shade due to your chemical composition which is around 50% silica, Mg (magnesium), Fe (iron) and also Ni (nickel).
FELSIC igneous rocks are LIGHT in color due to your chemical ingredient which is around 70% silica, K (potassium), Al (aluminum) with plentiful light mineral (in color) favor quartz and feldspar.

Igneous rocks have plenty of different textures depending upon rate of cooling (fast or slow).

Igneous rocks can be:


GLASSY - looks prefer a glass and also has no crystals (grains), rocks cooled very fast.
VESICULAR - has vesicles (air pockets) developed by escaping gases once the lava reached the Earth"s surface. Crystals room microscopic, rocks cooled fast.
APHANITIC - crystals space tiny, rock cooled quick from lava outside the Earth.
PORPHYRITIC - mixture of embedded crystals in a well groundmass. Cooled in two stages: magma cools slowly developing medium to huge crystals ad then those installed crystals mixed with Lava come in an explosion that cools really fast.
PHANERITIC - medium size to big crystals that room cooled native magma inside the Earth.

Name of rock = SCORIA

Type of rock = VOLCANIC/EXTRUSIVE

Composition = MAFIC

Cooling price = fast FROM LAVA

Texture = VESICULAR

Name of absent = BASALT

Type of absent = VOLCANIC/EXTRUSIVE

Composition = MAFIC

Cooling price = rapid FROM LAVA

Texture = APHANITIC (tiny Crystals)

Name of absent = GABBRO

Type of rock = PLUTONIC/INTRUSIVE

Composition = MAFIC

Cooling price = slow-moving FROM MAGMA

Texture = PHANERITIC (medium dimension crystals)

Name of rock = OBSIDIAN

Type of absent = VOLCANIC/EXTRUSIVE

Composition = FELSIC

Cooling price = quick FROM LAVA

Texture = GLASSY

Name of rock = PUMICE

Type of absent = VOLCANIC/EXTRUSIVE

Composition = FELSIC

Cooling price = fast FROM LAVA

Texture = VESICULAR

Name of rock = RHYOLITE

Type of rock = VOLCANIC/EXTRUSIVE

Composition = FELSIC

Cooling price = TWO phase COOLING: CRYSTALS COOLED SLOWLY and also THEY embedded IN LAVA EJECTED indigenous A VOLCANO

Texture = PORPHYRITIC (medium dimension crystals embedded in a fine groundmass)

Name of absent = GRANITE

Type of rock = PLUTONIC/INTRUSIVE

Composition = FELSIC

Cooling price = slow-moving FROM MAGMA

Texture = PHANERITIC (medium dimension crystals)

Name of absent = PEGMATITE

Type of rock = PLUTONIC/INTRUSIVE

Composition = FELSIC

Cooling price = slow FROM MAGMA

Texture = PHANERITIC (large size crystals)

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Magmatic intrusions and also lava operation - There are intrusions that magma asociated through igneous rocks. Some of the intrusions shown above are SILLS and DIKES.

LAVA operation - igneous material erupted ~ above the Earth"s surface. In a lava flow the height layer will certainly consist of SCORIA (gases escaped conveniently - microscopic crystals), the center layer will certainly consist of BASALT (rock cooled closed to the surface ar - small crystals), and also at the bottom the the intrusion eruption away from the surface ar GABBRO will type (rock cooled underground - large crystals).

SILLS - space horizontal igneous intrusions that never reach the surface. Because these rocks cool undeground, one can only discover BASALT and GABBRO. BASALT will be cool closer to the Earth"s surface and GABBRO will cool deep underground.

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DIKES - are vertical igneous intrusions that never reach the surface and additionally cool underground and there one can find only BASALT and GABBRO.

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