Structure:

Introduction: (upto 30 words) Give a brief introduction to hotspot volcanos

Body: (upto 100 words) Explain how Hotspot volcanos occur and form island chains in the middle of the ocean.

Conclusion: (upto 30 words) Conclude by pointing out that, the study of island chains formed by Hotspots help to understand plate tectonics.

Supporting Points:

1. In geology, a hotspot is an area of the Earth’s mantle from which hot plumes rise upward, forming volcanoes on the overlying crust. A hotspot's position on the Earth's surface is independent of tectonic plate boundaries, and so hotspots may create a chain of volcanoes as the plates move above them.
2. In much the same way that plumes rise buoyantly in a lava lamp, plumes of hot mantle rock are theorized to rise buoyantly from the deep mantle.
3. When a plume rises to the shallow mantle, it partially melts and the melt upwells to the surface, erupting as a hotspot volcano. Hotspot volcanism is unique because it does not occur at the boundaries of Earth’s tectonic plates, where other volcanism occurs.
4. The mantle plumes that form hotspots are thought to be relatively stationary, while tectonic plates are not. As a plate continues to move away from the lava stream, it carries built up volcanoes with it; as these volcanoes cool and subside, they can produce lines of islands, atolls, and seamounts known as hotspot tracks.
5. The youngest, most active volcanoes are situated directly over the plume while progressively older (extinct) volcanoes populate the surface of the tectonic plate downstream of the active hotspot, in the direction of plate motion.
6. Scientists can use the tracks of hotspot volcanoes to study how tectonic plates have moved through Earth’s history compared to mantle sources.
7. Hawaii is perhaps the most well-known example of a hotspot track. Here, volcanic activity on the Island of Hawaii is slowly being replaced by activity on nearby Loihi Seamount. The Hawaiian hotspot is believed to have been active at least 70 million years, producing a volcanic chain that extends 6,000 kilometers (3,750 miles) across the northwest Pacific Ocean.
8. While the hotspot volcanism theory successfully explains the linear relationship between age and distance within some long-lived volcanic chains (e.g., the Samoan and Hawaiian Islands), it does not give an explanation for the temporal and spatial pattern of volcanism within others (e.g., Cook-Australs, Marshalls, Gilberts, and Line Islands).

This has lead to scientific debate about whether hotspots are actually deep phenomena or even “fixed” in position, with some researchers abandoning the hotspot plume theory altogether.