Okeanos Explorer (EX1103L2): Exploration and Mapping, Galapagos Spreading Center: ROV, Mapping, and CTD

Vessel: NOAA Ship Okeanos Explorer; Expedition Dates: July 7 - 28, 2011

Project Principals: Jeremy Potter, NOAA/OAR/OER (Expedition Coordinator); Mashkoor Malik, NOAA/OAR/OER (Mapping Lead)

This cruise was composed of two legs. During the first, the Okeanos Explorer collected multibeam and meteorological/oceanographic (METOC) data during the ~ 15.5 day transit from San Diego to the area of operations in the Galapagos Spreading Center. For the second leg, primary objectives included utilization of the full suite of Okeanos Explorer capabilities (i.e., ROV, mapping, CTD, and telepresence). Daytime operations focused on ROV dives to explore targets identified using bathymetry collected during Leg I and from other ships during previous expeditions. Nighttime operations consisted of vertical CTD casts and multibeam data collection.

Paramount Seamount

Area

Paramount Seamount; Approximately 225 Nautical Miles North of the Galapagos Islands

Overview

Date:	July 14, 2011
Max Depth:	597.6 Meters
Bottom Time:	6 Hours 44 Minutes 2 Seconds

Purpose

The location of this dive on the eastern side of Paramount seamount at approximately 600 meters depth was chosen based on multibeam, backscatter and current data. The goal was to characterize the biological communities on the Seamount, and make comparisons with 2010 INDEX expedition to the Sangihe Talaud region in Indonesia.

Site of strong hydrothermal signal

Area

Site of strong hydrothermal signal; Approximately 175 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 15, 2011
Max Depth:	1976.8 Meters
Bottom Time:	6 Hours 23 Minutes 34 Seconds

Purpose

To descend with the ROV Little Hercules to a site on the Galapagos Rift where strong hydrothermal plume signals were detected a few weeks ago during tow-yo operations. Traverse toward WP2- Plume target 2a, exploring the vicinity for hydrothermal activity.

Site 2a

Area

Site 2a; Approximately 175 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 16, 2011
Max Depth:	1970.8 Meters
Bottom Time:	6 Hours 8 Minutes 31 Seconds

Purpose

Site 2a has light-scattering properties dozens of meters off the seafloor and a strong hydrothermal plume signal was located here during the first leg of this expedition. The goal of this dive was to explore an area near 1970 meters where fresh lava flows were observed at the end of Dive 02 and to continue exploration for active hydrothermal venting.

Site 2a

Area

Site 2a; Approximately 175 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 17, 2011
Max Depth:	1968.7 Meters
Bottom Time:	5 Hours 20 Minutes 55 Seconds

Purpose

Our seafloor target was a position 100 meters SW of our active hydrothermal plume signal (called 2a) near 1970 meters. This dive continued the exploration for hydrothermal activity on the Galapagos Rift where strong hydrothermal plume signals were detected.

Site 2a

Area

Site 2a; Approximately 175 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 18, 2011
Max Depth:	1972 Meters
Bottom Time:	5 Hours 41 Minutes 44 Seconds

Purpose

The purpose of this dive was to target a hydrothermally active area discovered during dive 04 that may have not been fully explored. From there, we plan to move east of the massive inactive sulfide towers located at the end of the dive 04 to explore to the East/Southeast in the axial graben.

Site 2c

Area

Site 2c; Approximately 190 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 19, 2011
Max Depth:	1975.1 Meters
Bottom Time:	6 Hours 29 Minutes 38 Seconds

Purpose

The goal of dive 06 was to begin exploration at approximately 1980m on the southwestern margin of the axial ridge and proceed northeast upslope to the top of the ridge and the EX1103 Plume Target 2C area, before continuing to the east.

Rosebud

Area

Rosebud; Rosebud hydrothermal vent site, approximately 300 Nautical Miles Northwest of the Galapagos Islands

Overview

Date:	July 20, 2011
Max Depth:	2449.7 Meters
Bottom Time:	4 Hours 25 Minutes 17 Seconds

Purpose

To locate an area that hosts the Rosebud hydrothermal vent site at 2450m for further exploration of the Rift in this region, which will likely be along east -west trending fissures just north of the field. Rosebud has not been visited since 2005, when Riftia tubeworms and bathymodiolid mussels dominated vent openings. The field was 60m x 40m with white seafloor markers, "A" and "B" on the eastern side, "F" and "L" centrally located, and "C" on the western side.

Site 4aE

Area

Site 4aE; Approximately 320 Nautical Miles Northwest of the Galapagos Islands

Overview

Date:	July 21, 2011
Max Depth:	2607.4 Meters
Bottom Time:	5 Hours 50 Minutes 21 Seconds

Purpose

To dive below a high hydrothermal plume signal discovered during the last leg of this expedition now referred to as "4a". This is an unexplored region, but multibeam surveys suggest that there is a well-defined axial volcanic ridge with walls separated by approximately 500 meters.

Site 4aW

Area

Site 4aW; Galapagos Rift eastern limb, approximately 320 Nautical Miles Northwest of the Galapagos Islands

Overview

Date:	July 22, 2011
Max Depth:	2581.4 Meters
Bottom Time:	6 Hours 37 Minutes 48 Seconds

Purpose

The objective of Dive 9 of this program was to descend to a location (85 54.648 00 46.104) on the eastern limb of the Galapagos Rift and to explore the landing site before moving to the west - northwest in search of hydrothermal vents. A strong hydrothermal plume signal (4a west) was observed a few weeks ago in this area. This area is ~1.7 kilometers west of dive 08 site, at a depth of 2560m.

Site 4aW

Area

Site 4aW; Galapagos Rift eastern limb, approximately 320 Nautical Miles Northwest of the Galapagos Islands

Overview

Date:	July 23, 2011
Max Depth:	2566.5 Meters
Bottom Time:	4 Hours 48 Minutes 20 Seconds

Purpose

To descend with ROV Little Hercules on Dive 10 of this program to the active hydrothermal field we discovered on the previous dive on the eastern limb of the Galapagos Rift just north of a east-west running fissure. The goal of this dive is to relocate the field, document what we believe to be small recently colonizing animals (e.g., tubeworm and mussels), and determine the E-W extent of the field, before continuing our exploration to the west.

Off-axis Sulfide Mounds

Area

Off-axis Sulfide Mounds; Approximately 300 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 24, 2011
Max Depth:	2716.9 Meters
Bottom Time:	3 Hours 42 Minutes 1 Seconds

Purpose

To locate and explore the Off-Axis Sulfide Mounds.

Ecuadorian Rift

Area

Ecuadorian Rift; 390 Nautical Miles Northeast of the Galapagos Islands

Overview

Date:	July 25, 2011
Max Depth:	2878.9 Meters
Bottom Time:	4 Hours 8 Minutes 29 Seconds

Purpose

To dive with ROV Little Hercules to an axial volcano near 85 01.967W 1 43.806N on the eastern side of the Ecuador Rift. There had been no previous visits to this volcano.