Mixing Zephyr Program
Dive 2936

Port Observer: Robigou
Starboard Observer: Juniper
Pilot: Williams
Date: 6/14/95

Summary

Dive Objectives: This dive goals are - Visit Clam bed and document site (diffuse flow)

- Document EM flow meter deployed in 1991

- Sample (major) white smoker at Clam Bed

- Check sonar map by zigzagging west-east on the horst until High Rise Field is reached.

- Boardwalk. Work on flange (at AB) video survey, temperature survey, sampling survey and finally recover complete flange in water-tight flange sampling box.

Summary: On descent we realize we’ll have to use transponders 7.5 and 8.5 for navigation on this dive. On bottom at 5446-7648 D2152 A21m H149. not very far from Clam Bed which we reach at 9:45. For one hour we work at Clam Bed. Sampling of the white smoker using manifold port outer major Temperature was 216C. (5439,7678,2186,2,206). Schulz's EM meter was documented by video for examination by ALVIN pilots for later recovery. Documenting the clams in the depression before heading north toward next way point.

10:19-11:44 zigzag Geology Heading toward 5500, 7800 first way point along a northern zigzag pattern to look at the geology of the valley between Clam Bed and High Rise and possibly better defining the SONAR map. We had problems with navigation since we crossed the base line during the progression of the sub northward, but we used distance traveled and heading to keep zigzagging.

-First encounter of an area with a white smoker and a large tubeworm field ( 5487,7784,2178,4,014).

-Second encounter of new area with large dead sulfide blocks and some hydrothermal activity, tubeworms and diffuse flow 5548,8103,2177,4,070

-Third area with hydrothermal activity. At least 3 chimneys, 2 dead and 1 active and tubeworm fields on both port and starboard as well as diffuse flow staining on sediments 5651,8152,2172,8,087

Arriving at High Rise. We are now encountering large active sulfide structures which are south of the Fairy Castle sulfide structure. We have reached what we call the High Rise Field. I see 2 spires 8 m high and there is a Debbie Stakes marker (#14). No black smoker on this structure 5679,8144,2173,9,108. Large tubeworm field in the typical High Rise setting. At the base of large fault offset and climbing up the wall on which top are located sulfide structures. 5705,8173,2160,4,142.

At Boardwalk 5726,8282. we arrived at Boardwalk on the south side of the structure and crab around toward the west to reach the north side. Then went up toward the top of the structure and found the markers AL and AB very rapidly. Work on flange at marker AB started 5751,8283,2144,10,103. Imaging the walls surrounding the flange (back, side, underneath). Imaging top of flange 5731,8339,2146,9,124. Imaging top of flange and front of flange with hand-held camera through forward porthole (Blee). High-T probe temperature measurements on top of the flange 23 measurements were taken in a suite of 4 lines from the marker to the edge of the flange in different directions. For details refer to drawings and explanations in dive narrative. Measurements of temperature inside the pool 335.8C maximum temp. Depth of pool 4 inches in center. Fluid sampling: Manifold sampling in pool Port inside major temp: 330.1C. Port gt temp: 329.2C. Manifold sampling of diffuse flow on top of flange. Starboard gt temp: 10.8C. Starboard outer major temp: 11.4C (DID NOT WORK). Starboard inside major temp: 9.8C 5752,8286,2147,11,139. Marker AB moved to the left side of flange 5751,8283,2146,12,095

Position during sampling of the flange, 5751,8283,2147,13,087. Taking still images from forward porthole of the flange scar left. And moving the marker AB back underneath the flange scar.