Mixing Zephyr Program
Dive 2934

Port Observer: McDuff
Starboard Observer: Allison
Pilot: Williams
Date: 6/10/95

Summary

Dive Objectives: 1) sample A1 and A4 vents at Milli-Q

2) evaluate Milli-Q as a site for camera deployment and deploy camera at either here or at Cannaport

3) survey Milli-Q for instrumentable flanges

4) continue Mesotech survey of the Bastille complex (not completed, replaced with survey of Grotto and Lobo)

5) survey Grotto, Lobo and Hulk for camera sites and instrumentable flanges (only Grotto examined)

Summary: We landed on the west wall. After orienting, we took a course ~065 toward Milli-Q flying without the bottom in sight (depth ~2165), lowering to the bottom in the vicinity of Milli-Q. Phillip almost immediately sighted the 1E marker. We examined the structure, looking for possible camera sites. After identifying one below marker A4, we proceeded to do the fluid sampling at A4 (~1115L), using the port side samplers in the order port outboard major, port inboard major, port gas tight. Temperature reached 364 C.

We then moved downslope to deploy the camera and the temperature probe. During deployment of the temperature probe we observed the camera lights on at 11:50:15L.

The smoker at marker A1 was then sampled (~1215L) (there is a cluster of three--two small ones at the edge of the structure and a third larger one closest to the marker and behind the other two). The starboard bottles on the manifold were used (starboard outboard major, starboard inboard major, starboard gas tight). Temperature reached 363 C.

We then circled Milli-Q, looking for flanges that would be suitable for instrumentation. None were found.

After a short break, we then transited north, toward the SE corner of Grotto, arriving ~1245L. We then began a reconnaissance of Grotto looking for both potential smoker and flange sites for instrument deployments. We moved up the east side of Grotto (between Grotto and Dante). There were many large (1-3 meters) blocks of oxidizing sulfide at the base of the structure. There were many large flanges along this wall with seemingly healthy fauna on the upper surface. However there was no indication of overflow from any of these and the ones we examined more closely were "dry" or extremely shallow (millimeters of fluid, with many small ridge of sulfide minerals filling the pool. Some portions appeared oxidized. At the northern end we moved up the structure and then moved slowly to the west, observing a series of smokers along this edge. Several of these looked suitable for a camera deployment include ones at (4942,6138,2188) heading 274; (4923,6141,2186) heading 080 and (4952,6144,2188) heading 321 (these were fixes off the 10-10.5 kHz pair). During this work within the Grotto we located the thermoelectric generator in the vicinity of marker K (about 1318L, we did not see marker K in the vicinity until later) and placed marker BA there.

We then completed the dive with a Mesotech survey of the Grotto-Lobo pair, running several N-S tracks from 6100 to 6200.