What Happens in an Underwater Lava Flow?

Lava, typically flowing at a scorching temperature of 1200 degrees Fahrenheit, can have catastrophic effects when it comes into contact with water. If a human is submerged in lava, all that remains is carbon and some minor mineral compounds. This phenomenon is eerily exemplified by the remains of a Roman soldier discovered during excavations at Herculaneum. The soldier's sword was melted into his thigh bone, indicating the extreme heat. Nearby skulls are also often surrounded by remnants of obsidian, created when the individuals' brains exploded due to the intense heat.

Underwater Lava Formation and Plate Tectonics

My grandmother and uncle, both passionate geologists, often shared stories about diamond formation at the ocean's depth. At the deepest points of the ocean, under immense pressure and with superheated lava, diamonds can sometimes form. While my grandmother's theory might not be entirely accurate, there is a possibility that lower-grade diamonds could form from the carbon in the hot magma lava.

Underwater volcanic activity plays a significant role in the formation of new land. The edges of tectonic plates often see lava pushing up along their perimeters, creating new ridges and landmasses. An example of this is the new sea mount south and east of Hawaii, known as Loihi, which is expected to break the surface within 10,000 years. This ongoing volcanic activity has been evident during my visit to Hawaii Island, where one can observe the creation of new land both above and below the ocean.

Geologic Impacts and Pillow Lava

The effects of underwater lava extend beyond the immediate area of the eruption. As lava flows into the water, it transforms into what is known as pillow lava. When lava emerges from underwater vents, it creates a hard crust as it cools. This crust prevents the interior from cooling too quickly, and pressure builds until the crust becomes too strong to contain the lava.

As the pressure increases, the lava breaks out at the weakest point, forming a new pillow further from the original source. This process repeats until the exit point freezes. This unique formation process results in a series of interconnected pillows, each larger than the last, creating a distinctive geometric pattern on the ocean floor. Pillow lava is not just a curious geological formation but also plays a crucial role in the expansion and evolution of oceanic crust.

Understanding the behavior of underwater lava and the formation of pillow lava is essential for advancing our knowledge of geologic processes and the dynamic nature of our planet. Whether it's volcanic activity creating new land or the transformative nature of pillow lava, these phenomena continue to fascinate scientists and adventure seekers alike.