laboratory 1 Flashcards
The 3 categories rocks can be classified in?
Igneous, sedimentary and metamorphic
What are igneous rocks?
IGNEOUS ROCKS: rocks formed when
molten material/magma or lava cools and
solidifies.
Visually, these rocks appear to have crystals and are NEVER LAYERED.
IGNEOUS ROCKS are further subdivided into INTRUSIVE and EXTRUSIVE IGNEOUS ROCKS
What are sedimentary rocks?
SEDIMENTARY ROCKS: rocks formed
from sediments, bits of preexisting rocks
and pieces of once-living organisms
(e.g., mollusks and other invertebrates)
Furthermore, SEDIMENTARY ROCKS:
➢ have layers
➢ feel gritty (i.e., rough texture/feels like
it is coated in sand)
➢ often break easily
What are metamorphic rocks?
IGNEOUS or
SEDIMENTARY ROCKS that have been
transformed by high pressure, high heat, and/or
contact with hot magma.
Find such conditions:
➢ deep in the Earth
➢ where tectonic plates meet
NOTE: Transformation/METAMORPHISM
process does NOT melt rocks, it just turns them
into DENSER (remember de
What ultimately forms igneous rocks and near what?
Molten rock/magma that ultimately forms IGNEOUS
ROCKS originates within Earth near:
➢ TECTONIC PLATE BOUNDARIES
➢ HOT SPOTS
As magma rises what are two things that can occur?
(i) MAGMA gets trapped below surface/never makes it to Earth’s surface.
(ii) MAGMA feeds active volcanoes and erupts onto Earth’s surface
These two fates result in different IGNEOUS ROCKS.
What does magma trapped below surface that cools slowly, solids over thousands or millions of years form?
Rocks formed this way = INTRUSIVE IGNEOUS ROCKS
Also known as PLUTONIC IGNEOUS ROCKS since PLUTO = Ancient Roman god of the underworld!
Since cool slowly, MINERAL CRYSTALS have time to grow to larger sizes
Examples of Igneous rock
Basalt, pumice, obsidian, rhyolite, scoria, dacite, granite, gabbro, diabase, diorite, pegmatite, peridotite
Examples of sedimentary rock.
breccia, caliche, chalk, chert, coal, conglomerate, diatomite, limestone, sandstone, shale, dolomite, siltstone, rock salt, gypsum, ironstone, coquina
Examples of metamorphic rock
marble, anthracite, gneiss, hornfels, mariposite, novaculite, quartzite, phyllite, schist, skarn, slate, soapstone
Characteristics of intrusive igneous rocks
-INTRUSIVE IGNEOUS ROCKS have COARSE GRAINED TEXTURE (i.e., they have crystals that
have grown to MACROSCOPIC/visible sizes)
-Within each rock, first CRYSTALS to form (i.e., first to solidify) have more regular shapes as can grow freely into surrounding molten rock.
-Later forming CRYSTALS forced to fill irregular spaces remaining between previously solidified/neighbouring minerals.
What if MAGMA escapes onto Earth’s surface via an active volcano?
EXTRUSIVE (or VOLCANIC) IGNEOUS ROCK forms when MAGMA/LAVA exits a volcano or rises up to surface through a fissure.
What is a fissure?
a crack or fracture in the rock
In extrusive rocks where and how fast does magma/lava cools down?
Here, MAGMA/LAVA cools above, on and/or very near to Earth’s surface.
MAGMA rising to surface can either get trapped below surface or feed active volcanoes and erupt onto surface.
Cooling/solidication of MAGMA/LAVA begins instantaneously and occurs rapidly due to cooler temperatures at surface/in atmosphere.
What does rapid cooling imply?
Rapid cooling means CRYSTALS don’t have time to grow as saw with INTRUSIVE IGNEOUS ROCKS.
Thus, EXTRUSIVE IGNEOUS ROCKS have FINE GRAINED TEXTURE (i.e., individual
grains/CRYSTALS too small to see with naked eye).
Characteristic of extrusive igneous rocks
➢ have GLASSY TEXTURE (e.g., OBSIDIAN which
does not actually contain MINERAL CRYSTALS)
➢ have gas bubbles trapped within (e.g., SCORIA)
What is a rock?
Naturally occurring solid mass/object made of one or more GEOLOGICAL MATERIALS.
What is geological materials?
include MINERAL CRYSTALS, NON-
MINERAL solids (e.g., glass), bits of other rocks, fossils
What does geological materials may be?
➢ ORGANIC (i.e., come from living organisms/have carbon and carbon-
hydrogen bonds)
➢ INORGANIC (i.e., not from living organisms, generally no carbon or at
least NO carbon-hydrogen bonds)
What is a crystal?
➢ solids whose ATOMS/MOLECULES/IONS are arranged in a
“highly ordered” repeating pattern
➢ solids that have a highly ordered MICROSCOPIC
arrangement of ATOMS.
Likewise, such solids are referred to as CRYSTALLINE
SOLIDS.
Can all solids be referred to as crystalline solids?
Not all solids are CRYSTALLINE SOLIDS.
Some solids (e.g., glass, igneous rock OBSIDIAN which is a
natural glass) are NON-CRYSTALLINE.
What would the opposite be called!?!
AMORPHOUS (aka NON-CRYSTALLINE): a substance whose
atoms are NOT arranged in a “highly ordered” pattern.
What is crystallization?
➢ Process by which CRYSTALS form and
grow.
Beyond the MICROSCOPIC arrangement,
MACROSCOPICALLY (i.e., to naked eye)
CRYSTALS have specific geometric shapes
with flat surfaces.
What is a mineral?
An INORGANIC, NATURALLY OCCURRING, HOMOGENOUS SOLID with DEFINITE CHEMICAL COMPOSITION and ORDERED/CRYSTALLINE ATOMIC STRUCTURE.
Inorganic characteristic of a mineral.
➢ not made up of living matter
➢ not derived/originating from living matter
➢ not made up of ORGANIC materials (generally
speaking, ORGANIC materials are materials containing
the element CARBON or at least not containing
CARBON-HYDROGEN bonds)
