Woods Hole Oceanographic Institution

Cruise Planning Synopsis


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AT42-17: Kelley "Pythia's Oasis"

Ship

R/V Atlantis

Vehicles

AUV Sentry, ROV Jason

Cruise Party

Deborah Kelley: Chief Scientist, Principal Investigator
Univerity of Washington, School of Oceanography 1501 NE Boat St P.O. BOX 357940 Seattle, WA USA 98195
+1 206 685 9556
dskelley@uw.edu

Departure: Sep 17, 2019

Newport

Arrival: Oct 3, 2019

Newport

Operations Area

Due west of Newport Oregon
Lat/Lon: 44° 29.0′ N / 125° 4.0′ W
Depth Range: 800 / 1400
Will the vessel be operating within 200 NM of a foreign country? NA
Are visas or special travel documents required? no

Science Objectives

During a single remotely operated vehicle (ROV) dive in 2015, a remarkable seep site called Pythia’s Oasis was discovered 19 km inboard from the toe of the accretionary prism of the Cascadia Margin at a water depth of ~1040 m. The site is unlike any seep yet described along active margins, hosting an intense fluid-dominated venting system issuing low-salinity, hydrocarbon-bearing fluids at 11.8 C, greater than three times above background seawater values. The emanating fluids carry low concentrations of suspended particles from a discrete orifice, reminiscent of a mid-ocean ridge hot spring. The bubble component of the vent rises as a plume > 450 m into the overlying hydrosphere; it has been active for at least three years. A second adjacent site includes an extensive collapse zone hosting multiple seeps issuing diffuse, schlieren flow reflecting egress of warm and/or low salinity fluids. Two other plumes have also been documented. The goal of this two-year collaborative effort is to characterize the geology and chemistry of this extraordinary seep site to test three specific hypotheses:

1. Fluids originate from a meteoric source, and thus, play no role in the seismogenic behavior of the margin, but may contribute to element transport between land and ocean, impacting the current understanding of coastal hydrogeology.

2. Fluids originate from smectite-illite dehydration in the accreted sediments rather than at the plate boundary, providing important information on fluid production and overpressure development within the accretionary prism above the plate boundary.

3. Fluids originate from high temperature metamorphic reactions at depth in the seismogenic region of the Cascadia Subduction Zone (CSZ), resulting in extreme overpressures at the plate boundary. If so, either these dehydration reactions explain the partially locked behavior of the fault in this section of the margin or suggest that the locked seismogenic zone may not correspond to moderate overpressures as postulated for Nankai and Costa Rica.

Science Activities

During this expedition utilizing Jason and Sentry, the key science activities include 1) completing a high resolution bathymetric map of the Pythias site and surrounding area; 2) completing a photomosaic of the keep seep sites for documentation of the geology, tectonics, seeps, and associated biology, 3) conducting multiple surveys with Jason for sampling and seafloor/seep characterization; 4) fluid sampling of the seep sites using IGTs' and major samplers for fluid chemistry; collection of multiple push cores for pore fluid chemistry, 5) conduting a heat flow probe survey (Rob Harris-OSU) in a 'pogo' fashion; and 6) use of the OSU core facility infrastucture (Paul Walczak -container, flat rack, coring shack, and Hiab crane) to recover a series of cores.

Additional Info

Pre-cruise Planning Meeting: Teleconference

Stations:

  Station 1
  Distance: 50-60
  Days: 16
  Latitude: 44° 29.0’ N
  Longitude: 125° 4.0’ W

Supporting documentation:

Funding

Funding Agency: NSF
Grant or contract number: OCE 1658201

Scientific Instrumentation for R/V Atlantis

Other Science Vans:

Shipboard Equipment

12 kHz Pinger for Wire Use
A-Frame
ADCP 75 kHz
Bathymetry System 12 kHz
Bathymetry System 3.5 kHz
Crane
Deionized Water System
Fume Hood
Multibeam
Navigation - Heading
Navigation - Position
Science Underway Seawater System
Sippican XBT System (Mark 21)
Transponder Navigation - Sonardyne USBL

Shipboard Communication

Basic Internet access via HiSeasNet

CTD/Water Sampling

911+ Rosette 24-position, 10-liter bottle Rosette with dual T/C sensors
SBE43 oxygen sensor
Wet Labs C*Star transmissometer (660nm wavelength)
Wet Labs ECO-AFL fluorometer
Wet Labs FLNTURTD Combination Flourometer and Turbidity Sensor

Critical CTD Sensors

pH

MET Sensors

Air temperature
Barometric Pressure
Relative Humidity
Short Wave Solar Radiation
Wind speed and direction

Sediment Sampling

Gravity corers

Sample Storage

Climate Controlled Walk-in
Freezer -70°C 25 cu. ft.
Freezer -70°C 3.2 cu. ft. ea.
Refrigerator 8.6 cu. ft.
Scientific Walk-in Freezer
Scientific Walk-in Refrigerator
Storage Notes:

Navigation

Will you be using Long Base Line (LBL) navigation? no
How many nets? null
How many tansponders? null
Will you be using Ultra-short baseline (USBL) navigation?no

Navigation

GPS
USBL
Navigation Notes: May conduct concurrent sentry and jason dives

Winches

CTD Winch with .322" Electro-mechanical wire
Hydro Winch with .25" hydro wire
Trawl Winch with 9/16th trawl wire
Winch Notes: See note under OSU coring facility - during precruise meeting with Paul Walczak and Evan Solomon (Co-Chief) it will be important to talk about use of the Alvin LARS system for coring.

Wire use and application

CTD Winch with .322" Electro-mechanical wire
Trawl Winch with 9/16th trawl wire
Winch Notes: See note under OSU coring facility - during precruise meeting with Paul Walczak (OSU) and Evan Solomon (UW-Co-Chief) it will be important to talk about use of the Alvin LARS system for coring and for the heat flow probe (Rob Harris - OSU).

Standard Oceanographic Cables

Slip ring required? no
Non-standard wire required? no
Traction winch required? no
Science Van 1
Type/size: Storage Van same size as blue Jason van Location: Can store forward on Atlantis
Water: Power:
Science Van 2
Type/size: Flat rack for cores - same size as storage van Location: stored aft on the starboard side
Water: Power:
Science Van 3
Type/size: Coring Shack Location: starboard side just aft of the door for the CTD boom
Water: Power:
Science Van 4
Type/size: Shipping container (may combine with 1st mentioned container above Location: will discuss in precruise meeting
Water: Power:

Specialized Deck Equipment

Mooring Deployment/Recovery Equipment Required: no Type: 
Cruise Specific Science Winch Required: yes Type: Heat flow and coring
Nets Required: no Type: 

Over the Side Equipment

Will you be bringing any equipment (winches, blocks, etc.) that lowers instruments over the side? yes Details:
Hiab crane - starboard side just aft of the door for the CTD boom for coring

Special Requirements

Elecrical Power: no Identify 
Equipment Handling: no Identify: 
Inter/intraship Communications: no Identify: 
Science Stowage: no Identify: 
Water: no Identify: 

Additional Cruise Items/Activities

Explosive Devices:no Portable Air Compressors:no Flammable Gases:yes Small Boat Operations:no SCUBA Diving Operations:no

Hazardous Material

Will hazardous material be utilized?yesDescribe deployment method and quantity:
Will discuss during precruise

Radioactive Material

Radioiosotopes:no

Additional Information

Is night time work anticipated on this cruise?yesSpecialized tech support (Seabeam, coring, other):
Jason-sentry dives, coring, and heat flow surveysOther required equipment and special needs:

Scientific Instrumentation for HOV Jason



Current Chart(s):

Site Survey

Will you provide detailed charts of the work area(s)?no
If no, willl you need R/V Atlantis to generate maps of the work area(s)?no
Will you need post-dive maps of the work area generated?no

Navigation

Will you be using Long Base Line (LBL) navigation? no
How many nets? null
How many tansponders? null
Will you be using Ultra-short baseline (USBL) navigation?no
Will you be using Doppler/GPS navigation? no
What type of samples do you expect to collect?Sediment, carbonates, animals (maybe), fluids (IGT's) and majors

Elevators

Will you be using elevators to transport samples to the surface?yes
If yes, how many would you anticipate? perhaps would like to have it onboard, but may not use

Science Supplied Equipment

Are you supplying equipment to be used on HOV Jason yes
Has this equipment been used on Jason before? yes
Please give a brief description of the equipment, its intended purpose, the cruise # it was last used on if any and its deployment method.
We will supply the IGT gas-tight samplers - will have been used on AT42-12 Regional Cabled Array cruise
Does this equipment use an external pressure housing? yes
If yes, what is the pressure rating?
and test pressure?
Has the pressure housing been tested per Alvin Pressure Test requirements? yes
Pressure housing schematic with dimensions and include air and water weights.
Does the equipment have an associated computer or control panel for remote operation from the personnel sphere? no
Air weight of this equipment?
Water weight of this equipment?
Does the equipment require data or a power interface from the vehicle? yes
Does this equipment require hydraulic inputs from the vehicle? no
Hydraulic schematic of the equipment requirements.
Does this equipment require manipulation? yes
If yes, please describe how the equipment is to be manipulated:
Placement of nozzle in seep sites
Will this equipment be deployed off the vehicle? no
If yes, please describe how the equipment is intended for deployment:
No only includes placement by the manipulator into the sampling site
If yes, will the equipment be disconnected from the vehicle and left in situ? no
How long will the deployment be?
Will the equipment be recovered by the same vehicle? no
If recovering equipment deployed with another vehicle, provide pressure rating:
and test pressure:
Does this equipment use any glass spheres for either buoyancy or as pressure housings? no

Hazardous Material

Will hazardous material be utilized?no
Describe deployment method and quantity:

Additional Information

Brief operations description or comments:

Scientific Instrumentation for AUV Sentry



Current Chart(s):

What type of samples do you expect to collect?Only geophysical data and imagery

Site Survey

Will you provide detailed charts of the work area(s)?yes
If no, willl you need R/V Atlantis to generate maps of the work area(s)?no
Will you need post-dive maps of the work area generated?no

Navigation

Will you be using Long Base Line (LBL) navigation? no
How many nets? null
How many tansponders? null
Will you be using Ultra-short baseline (USBL) navigation?no
Will you be using Doppler/GPS navigation? no

Science Supplied Equipment

Are you supplying equipment to be used on HOV AbeSentry no
Has this equipment been used on AbeSentry before? no
Please give a brief description of the equipment, its intended purpose, the cruise # it was last used on if any and its deployment method.
Does this equipment use an external pressure housing? no
Has the pressure case been tested to the anticipated depth of deployment?& no
Pressure housing schematic with dimensions and include air and water weights.
Air weight of this equipment?
Water weight of this equipment?
Does the equipment require data or a power interface from the vehicle? no
Does the equipment meet the electrical requirements of the Sentry User Manual? no

Additional Information

Brief operations description or comments:

Checklist & Notes

Checklist

U.S. Customs Form: no
Diplomatic Clearance: no
Date Submitted:
Date Approved:
Agent Information:
Countries:
Notes:
Isotope Use Approval: no
Isotope Notes:
SCUBA Diving: no

Checklist

SSSG Tech: