USGS CMG P-2-07-MB Metadata

Three days of vibracoring with the ROV Ventana's newly outfitted 14'
aluminum cores were planned in the upper Monterey Canyon. The primary goal was
to acquire an approximately 130-meter long transect of cores across the
sediment waves in the Monterey Canyon floor at water depths of approximately
285 meters. Processing and analysis of these cores will be used to study the
origin of the sediment waves. High resolution AUV mapping of the canyon floor
and sediment waves was acquired during a previous MBARI cruise on June 18, 2007.

Vibracores up to 14 feet in length with aluminum liners were obtained
with the ROV Ventana.  The cores were logged on a GeoTek whole-core-logger at
USGS on the day following their collection so that results could be used to
redirect the ongoing core collection.  The cores will be used to study the
origin of the sediment waves.

1400/JD177 R/V Point Lobos departs Moss Landing


1610/JD177 ROV Ventana dives for first core


2200/JD177 ROV Ventana dives for last core


1630/JD177 R/V Point Lobos arrives in Moss Landing


1400/JD178 R/V Point Lobos departs Moss Landing


1515/JD178 ROV Ventana dives for first core


2140/JD178 ROV Ventana dives for last core


2245/JD178 R/V Point Lobos arrives in Moss Landing


1400/JD179 R/V Point Lobos departs Moss Landing


1510/JD179 ROV Ventana dives for first core


2155/JD179 ROV Ventana dives for last core


2300/JD179 R/V Point Lobos arrives in Moss Landing


This cruise was the first use of a 14' aluminum core tube with the ROV
Ventana's vibracoring system.  A Homer Beacon was used to position the cores.
The core sites within 60 meters of the beacon were selected by diving to the
beacon, then moving off on a course of 290o or 110o to a pre-selected
distance.  Core sites further away were approached using ROV navigation to
locate the general area (~10m) and using the beacon to record the range.
Eighteen cores were collected along the transect.  The last core was taken
where the bottom was suspected to be softer sediment to test the full
penetration of the 14' core tube.      Cores recovered on the first day
recovered a much shorter amount of sediment in the cores than was expected.
Before each core was removed from the ROV Ventana, water was drained from the
portion of the core tubing not filled with sediment by using a hacksaw to
create a small hole in the core tube above the sediment.  Cores were then
capped, labeled, and split into sections (if core was over 1.5m).  Alterations
were made on the second and third days of coring to increase the penetration
of and recovery in the core tube.

MBARI's remotely operated vehicle (ROV) Ventana was used to obtain
vibracores. The ROV Ventana had a 14' aluminum core tube attached to the
vibracoring system in addition to the underwater cameras it typically carries.
The ROV Ventana is connected to the R/V Point Lobos by a surface slack cable
through which it communicates with pilots in the onboard control room.  The
cores were positioned relative to a Homer Beacon that was placed at (36.7931N,
121.8438 W) during the first dive and removed at the end of the third day of 
coring.