Approaching the Red Planet from the Kitchen

Approaching the Red Planet from the Kitchen
by Riko Seibo
Tokyo, Japan (SPX) Jan 29, 2025

Rootless cones, small volcanic landforms typically ranging from several meters to a few hundred meters in diameter, form through explosive interactions between surface lava and water bodies such as lakes and rivers. Unlike conventional volcanoes that arise from deep magma sources, rootless cones emerge when lava covers a water-containing layer, triggering bursts of steam and gas.

These features, also known as pseudocraters, are prevalent in Iceland, with smaller occurrences along the coastline of Hawaii's Big Island. However, extensive rootless cone fields have been observed on Mars, making their formation mechanisms an important subject in planetary geology.

Associate Professor Rina Noguchi and graduate student Wataru Nakagawa from Niigata University conducted controlled laboratory experiments to replicate the formation of rootless cones using a creative approach. They employed heated starch syrup as a stand-in for lava and a blend of baking soda and cake syrup to simulate a water-containing substrate.

In natural environments, lava reaches temperatures above 1000C, leading to rapid vaporization and expansion of water, driving explosive interactions. However, starch syrup only heats up to approximately 140C before caramelizing, which is insufficient to generate steam explosions.

To circumvent this limitation, the researchers leveraged the thermal decomposition of baking soda - a chemical reaction commonly seen in making karumeyaki, or Japanese honeycomb toffee.

When heated by the syrup, sodium bicarbonate releases carbon dioxide, causing intense foaming that mimics the explosive processes involved in rootless cone formation. Cake syrup was introduced to control viscosity. By varying the syrup thickness in a beaker, the researchers examined how vent size and number were influenced.

"We observed that conduits often failed to maintain their structure because they were disrupted by nearby forming conduits," explained Assoc. Prof. Noguchi. Their findings indicate that conduit competition, alongside water competition, plays a crucial role in rootless cone distribution.

Thicker syrup layers exhibited more intense conduit competition, leading to a higher failure rate among conduits - consistent with Mars, where thicker lava deposits are associated with fewer rootless cones. Conversely, in areas with abundant conduits, explosions diminished due to water scarcity, resulting in smaller cone edifices. These findings align with Martian observations where regions covered by thin lava sheets show few or no rootless cones.

Further evidence supporting this concept comes from failed conduit structures seen in terrestrial lava deposits, suggesting that conduit competition is a universal factor in rootless cone development. These experimental results, combined with geological surveys, underscore the importance of conduit merging and separation, driven by lava thickness, in shaping rootless cone distribution and size.

This study not only deepens our understanding of rootless cone formation on Earth but also enhances interpretations of similar landforms on Mars. Moving forward, researchers plan to integrate detailed fieldwork with remote sensing data to refine formation models, thereby improving assessments of past environmental conditions linked to rootless cone development.

Research Report:Experimental verification for self-organization process on the spatial distribution and edifice size of rootless cone