Several kilometers from a volcano, a geologist observes an old lava flow made up of dark-colored basalt rock. The geologist infers that the lava must have had
a.
high silica content.
b.
high viscosity.
c.
low viscosity.
d.
medium viscosity.
Answers
The correct inference of geologists, in this case, is given by option c: low viscosity.
- Dark rocks that are found near volcano mountains are called basalt rocks are igneous stones formed from the sudden cooldown process of lava after its eruption which has a very low viscosity.
- The fluidity of lava is limited by its viscosity. Low viscosity indicates that massive lava pours from the volcano in this situation.
- In this case, the temperature of volcanic eruption is also very high or can be said highest.
- Also, the silica content, in this case, is very low because significant silica content implies that the viscosity of lava is high and its fluidity is low.
- Hence, in this case, geologists infer that the viscosity of lava must have had been low because of composition factors, temperature, and igneous rock.
Answer:
The geologist infers that the lava must have had c.low viscosity
Explanation:
The old lava flow observed by the geologists' several kilometres from the volcano was the dark-coloured basalt rocks which are formed from the abrupt cooling down of the magma.
These rocks have low viscosity and low gaseous content so they travel far than the actual site of the eruption. They flow down the side of the volcano to the rivers of the hot magma. These eruptions are not very fatal to human life.
These rocks have a low silica content which causes their viscosity to be low and makes them resistant to flow. So, they move quickly and move around more than 20 kilometres from the original site.
So, the geologists concluded that these basalt rocks which were found several kilometres from the volcano had low viscosity.
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