The Earth's heat loss from the planet's crust baffled scientists for decades, until now. Scientists discovered a new class of hydrothermal vent system that could precisely explain previous global climate.
A hydrothermal vent is an opening in the seafloor out of which flows mineral-rich water that has been heated by magma. The new seafloor vent system could clear up the long-standing debate between actual observations that the Earth's crust is losing heat and the Earth's theoretical cooling rate.
The discovery was made by researchers from the University of Southampton and the National Oceanography Centre (NOC) in the United Kingdom. The research team used a combination of remotely operated vehicles and robot-subs to observe the vent system on the seafloor.
"Theory has long predicted that there must be more cooling in certain locations on the Earth's crust than we could account for using the known mechanisms and this new class of hydrothermal vent system may account for that difference," said NOC geologist Bramley Murton, who supervised the research.
Other hydrothermal vent systems use volcanic heat from magma chambers. The newly discovered hydrothermal vent system type makes use of hot rocks being pushed upward and toward the seabed by tectonic spreading centers, which are low-angle faults.
The research team believes that the new hydrothermal vent system type can be found across the globe in various tectonic seafloor spreading locations. The new vent systems will shed new light on the Earth's cooling mechanism, added Murton.
The new hydrothermal vent system type was discovered during a Caribbean expedition at the Von Damm Vent Field. The driving process of the new vents is not completely understood, rendering them unaccounted for in existing scientific models that explain how chemistry and heat travel upward from the Earth's crust.
The new vents are also nearly invisible to the conventional techniques utilized in searching for hydrothermal vents. The research was published in the journal Nature Communications on Dec. 22, 2015.
To measure the vent field, the team used sonar on an autonomous underwater vehicle, the Autosub6000, which then mapped the vent field. The team then sent a remotely operated vehicle (ROV) to the vents to collect mineral samples and hydrothermal fluids. The ROV's multi-beam sonar was also utilized to produce a high-resolution map.
An analysis of the samples proved both chemistry and minerals were different form the ones taken from other hydrothermal vents. The chimneys and mounds found in other vents are mostly made up of copper sulfides and iron, while on the Von Damm Vent Field, the 50-meter-tall (almost 165 feet) chimneys and mounds are largely made up of talc, a mineral rich in magnesium.
“This research also means that ocean models of magnesium and calcium budgets will need to be updated and could lead to more accurate insights into the Earth’s past climate,” the researchers concluded.
Photo: NASA Goddard Space Flight Center | Flickr