eq: what differences exist between types of lava flow?
TRANSCRIPT
VOLCANOES: LAVA FLOW
EQ: What differences exist between types of lava flow?
LAVA FLOW Depends on:
TemperatureSilica content/Chemical compositionSlope of the landViscosity (the state of being thick, sticky,
and semifluid consistency)
TYPES OF LAVA Pillow Lava Pahoehoe (paw-hoey-hoey) A’a (ah-ah) Block Lava Rhyolite Lava (Rie-o-lite)
PILLOW LAVA Most abundant type of lava Large, elongated, interconnected lobes
that are elliptical or circular in cross-section
Important when looking at old rock sequences Indicates the presence of water
The underwater equivalent to pahoehoe Made mostly of basalt
PILLOW LAVA
PILLOW LAVA
PILLOW LAVA
PAHOEHOE 2nd most abundant type of lava flow. Smooth, billowy, ropy surface Relatively thin flow (few inches to a few
feet thick) Lava cools slowly, moves slowly Made mostly of basalt
PAHOEHOE
PAHOEHOE
PAHOEHOE
A’A Rough, jagged surface Aa lava flows tend to be thicker
compared to pahoehoe Cools quickly and moves fast Made mostly of basalt
A’A
A’A
A’A
BLOCK Block lava has a surface comprised of
large angular blocks. Block lava also refers to solid rock that
is ejected during an eruption.
BLOCK
BLOCK
BLOCK
RHYOLITE Rhyolite Lava is light in color, contains
69% silica or more. Rich in potassium or sodium.
RHYOLITE
RHYOLITE
RHYOLITE