Page 49: of Marine Technology Magazine (June 2020)

Researched & Written by Celia Konowe

Monterey Bay Aquarium Research Institute

MBARI: Hydrothermal Mapping is Heating Up

A recent paper by Monterey Bay seawater, the dissolved minerals crystal- tectonic (lasting 5,000 years, when the

Aquarium Research Institute (MBARI) lise, creating spires and chimneys up to 25 seafoor cools and contracts, forming has revealed almost 600 hydrothermal metres (80 feet) tall. cracks and faults); and hydrothermal (last chimneys around the Endeavour Segment Researchers few MBARI’s autonomous a few thousand years, when resurgent of the Juan de Fuca Ridge, about 350 ki- underwater vehicle (AUV), D. Allan B., magma heats fuids that percolate up lometres (220 miles) northwest of Wash- over the seafoor during seven surveys in through the cracks, forming vents). ington State. The vents, located in a valley 2008 and 2011, mapping the area at about Further implications for this work about 14 kilometres (8.6 miles) long and 1.25-metre (4-foot) resolution. Overall, include using MBARI’s new maps to plan 1.5 kilometres (0.9 miles) wide, has been the AUV completed 140 hours of dives research dives and the location of moni- studied previously, but never mapped until and mapped about 62 square kilometres toring equipment. now because of diffcult access. (24 square miles). Additionally, data can be used to esti-

Hydrothermal vents are created by Based on their work at Endeavour and mate the volume and mass of hydrother- magma beneath the seafoor that heats other mid-ocean ridges, researchers mal deposits in the chimneys, which is water within the surrounding bedrock, propose that these ridges may go through critical for understanding the distribution emerging from the seafoor in the form three phases of evolution: magmatic (last- of metal-rich rocks around vents, some of underwater seeps and geysers. When ing up to tens of thousands of years, when of which have been targeted for deep-sea this heated mineral water meets freezing magma erupts and covers the seafoor); mining.

A computer- generate view of the seafoor that shows some of the hydrothermal chimneys in the Endeavour hydrothermal vent feld. © 2020 MBARI www.marinetechnologynews.com

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