Basic Lava - Characteristics of Lava - Geography Notes

Basic lava is non-acidic and less viscous. Basic Lava flows for long distances before solidifying, it has gentle sides. Basic lava has a high iron and magnesium content but a low silica content. It has a darker appearance due to its high concentration of ferromagnesian minerals. In this article, we will discuss Basic Lava which will be helpful for UPSC/IAS exam.

Table of Contents

Basic Lava
Less Viscous
Basic Lava vs Acidic Lava
Conclusion
FAQs
MCQs

Basic Lava

What is Basic Lava?

Basic lava comes from shield volcanoes as it runs and flows faster because of low viscosity.
Viscosity is the resistance of a fluid to gradual deformation by shear or tensile stress is characterized as viscosity. In other terms, viscosity refers to the reluctance of a fluid to flow.
The iron and magnesium content in basic lava is high, whereas the silica level is low.
Because it is rich in ferromagnesian minerals, it has a darker appearance.
The resulting volcano has a large circumference and is gradually descending, forming a flattened shield or dome.
Volcanic rocks found where magma erupts to the surface are classified into four major types, or “clans”—basalt, andesite, dacite, and rhyolite.
Along the constructive boundaries, shield lava flow is prevalent (divergent boundary).

Basic Lava

Other Relevant Links
Active Volcanoes	Dormant Volcanoes
Extinct Volcanoes	Volcanic Materials
Types of Volcanoes	Acidic Lava

Less Viscous

Why is Basic Lava Less Viscous?

Basic lavas are the hottest lavas, with temperatures around 1,000 degrees Celsius and high fluidity.
They are dark-colored basalt with high iron and magnesium content but low silica content.
They emerge from the volcanic vent silently and aren't particularly explosive.
They move easily at a speed of 10 to 30 miles per hour due to their tremendous fluidity.
They have a wide range of effects, spreading out as thin sheets across long distances before solidifying.

Basic Lava Vs Acidic Lava

Basic Lava vs Acidic Lava

Basic Lava	Acidic Lava
Contain small amount of silica Highly fluid Low melting point Fast flowing Travel long distances Build gently sloping cones Quiet and without much explosive activity	Contain a large amount of silica Highly viscous/ sticky High melting point Slow flowing Seldom travel far Build steep-sided cones Explosive volcanic activity

Conclusion

Basic lava, also known as mafic lava, is characterized by its low silica content and high iron and magnesium content. While basic lava eruptions are generally less explosive than acidic lava eruptions, they can still pose hazards. Fast-flowing lava can inundate areas, and the release of volcanic gases can pose health risks.

Other Relevant Links
Geography Notes	Physical Geography
Geomorphic Processes	Geomorphology
Distribution of Oceans and Continents Basins	Minerals and Rocks
Endogenic Processes	Exogenic Processes

FAQs

Question: What is basic lava and how does it differ from other types of lava?

Answer: Basic lava, also known as basaltic lava, is characterized by its relatively low viscosity and high fluidity, allowing it to flow easily across the landscape. It is rich in magnesium and iron, resulting in a dark coloration. In contrast to acidic or intermediate lavas, which are more viscous and can trap gases, basic lava tends to produce gentle eruptions that create broad, shield-shaped volcanoes. The chemical composition and physical properties of basic lava influence its behavior during eruptions and the landforms it creates.

Question: What are the primary characteristics of basic lava?

Answer: The primary characteristics of basic lava include its low viscosity, high temperature (typically between 1000°C to 1200°C), and fluidity. These properties allow it to travel long distances from the eruption site before solidifying. Basic lava usually contains a high percentage of silica, along with significant amounts of iron and magnesium. This composition leads to the formation of basalt rock upon cooling. Additionally, basic lava is associated with less explosive volcanic activity, resulting in the formation of extensive lava flows and shield volcanoes.

Question: How is basic lava formed in geological processes?

Answer: Basic lava is formed from the partial melting of the Earth's mantle, particularly in tectonically active regions such as mid-ocean ridges and hotspots. When pressure decreases or temperatures increase sufficiently, mantle rocks melt to produce magma that is rich in iron and magnesium. As this magma rises towards the surface, it undergoes a decrease in pressure, leading to its eruption as lava. The solidification of this lava upon cooling forms basalt rock, which is a common type of igneous rock found in the Earth's crust.

Question: What types of landforms are created by basic lava flows?

Answer: Basic lava flows create distinctive landforms, primarily shield volcanoes and basalt plateaus. Shield volcanoes are characterized by their broad, gentle slopes formed by the accumulation of low-viscosity lava that can travel long distances. These volcanoes often have non-explosive eruptions, leading to the gradual buildup of layers. In contrast, extensive basalt plateaus form when large volumes of lava erupt from fissures, spreading over wide areas and solidifying to create flat, expansive landforms. Both landforms are indicative of the fluid nature of basic lava.

Question: What is the significance of basic lava in the context of volcanic activity?

Answer: Basic lava is significant in the context of volcanic activity because it influences the style and impact of eruptions. Its low viscosity allows for less explosive eruptions, reducing the risk to nearby communities compared to more viscous lavas. The formation of shield volcanoes from basic lava plays a crucial role in shaping the landscape and contributing to the Earth's geological features. Additionally, studying basic lava helps scientists understand volcanic processes and predict future eruptions, enhancing disaster preparedness in volcanic regions.

MCQs

1. What is another name for basic lava?

A) Rhyolitic lava
B) Andesitic lava
C) Basaltic lava
D) Pumice lava