Program Focus 3: Scientific Seafloor Coring

The modular Seafloor Drill (SFD) program being launched by Global Oceans and Fugro for scientific seafloor coring has significant potential for accelerating research in several important areas, including research into the deep biosphere, geophysics, past deep-water structure, and sea level research. Our lab anticipates developing proposals to utilize these new tools and we look forward to working collaboratively with Global Oceans to optimize their use on multi-project cruises.

Jess F. Adkins, Ph.D., Professor of Geochemistry and Global Environmental Science, California Institute of Technology, Division of Geological and Planetary Sciences, Pasadena, CA, USA

Geotek Ltd is partnering with Global Oceans and Fugro Worldwide to support scientific analysis of cores obtained from the modular seafloor drills deployed on Global Oceans expeditions. Geotek has a long association with scientific coring campaigns and is uniquely experienced in both the academic and commercial sector offshore operations. Geotek has a wide range of skills and expertise ranging from core handling to detailed core analysis that will offer significant value to scientific seafloor coring. 

“Geotek’s sea-going modular core processing, Multi-Sensor Core Logger (MSCL), and X-ray CT laboratories installed on Global Oceans MARV vessels will provide a suite of advanced instruments, together with technical support, to enable consistent, accurate and cost-effective scientific analysis of cores.

Peter Schultheiss, Ph.D., Founder & Managing Director, Geotek Ltd, UK. Participant in over 50 ocean-going expeditions worldwide on academic and commercial oceanographic research, survey, drilling and deep submersible vessels.


 

MARV-DEPLOYED MODULAR SEAFLOOR DRILLS

SFD-Deploy_2Global Oceans and Fugro, headquartered in the Netherlands, have formed a strategic alliance to develop a long-range program for mobilizing Fugro’s modular seafloor drilling systems (SFDs) for scientific seafloor coring. This effort will engage with scientists in several disciplines that utilize seafloor coring in their research to align scientific operational requirements with program deployment.

The Fugro systems integrate proven drilling technology with ROV telemetry (image lower left) in two seafloor-operated drills – Seafloor Drill 1 and Seafloor Drill 2. This strategy aligns with Global Oceans’ objective of enabling utilization of commercial sector resources for scientific research, especially where they are facilitated by deployment from MARV vessels.

The alliance also makes available to the science community the extensive technical resources of Fugro, a global offshore technology services provider, committed to bringing the SFDs into productive service for scientific research – optimized for deployment by Global Oceans for collecting scientific data and cost-rationalized to align with research funding.

SFD1OPENING AVENUES OF RESEARCH

The SFD’s functional capacity and maximum operational depth provide several advantages in obtaining cores in the “intermediate” range of core lengths – up to 150 meters – which is between cores of several hundred meters in length obtained from ship-based drill rigs with large derricks deployed through the International Ocean Discovery Program (IODP) program; and shorter cores in the range of 10-40 meters available from gravity and piston coring.

When coupled with the SFD’s deep operational rating to 4,000 meters of water depth, this intermediate-range coring capacity opens up a greater expanse of the seafloor, especially for deep biosphere research and deep ocean structure studies utilizing pore fluid analysis (see below).

The design of the SFDs also revolutionizes scientific drilling in shallow water environments which is important for studies of submerged reef sequences. The ability of the SFDs to operate while sitting on the seabed, rather than from a riser vessel, confers an advantage because operational integrity is not compromised by excessive ship motion often encountered with sea state variability in shallower waters. Coupled with the smaller scale of deployment logistics for SFDs and the ability to deploy these systems from chartered vessels with the Global Oceans MARV model, the result is an improved capacity for economically scaling up sampling of submerged reefs globally.

MAPPING RESEARCH NEEDS TO SFD TECHNOLOGY

ROV-vanA structured process of working with the science community to map scientific coring needs onto SFD technology and operational capacity is being developed by Global Oceans and Fugro Worldwide in the Netherlands.

Scientific application of the SFDs requires definition of core specifications, quality thresholds for scientific analysis, and the costs associated with deployment. Technical challenges common to scientific coring that can be effectively addressed by the SFDs include:

  • Ensuring stratigraphic correlation and recovery between adjacent cores
  • Operational performance on soft seabed and slopes
  • Correlating pore fluid profiles accurately between adjacent cores, by core depth
  • Maintaining retrieved core integrity through reef sequences comprised of coral, reef rubble and sand

SFD-Ops-4

PARTNERSHIP WITH GEOTEK

Enabling a rapid assessment of quality and lithology of sampled cores is often critical to realizing research objectives on an expedition. Global Oceans and Fugro Worldwide are collaborating with Geotek Limited in the UK to achieve this with a range of core processing, Multi-Sensor Core Logger (MSCL) and X-ray CT systems as an integrated component of SFD field support. This analytical capacity is housed within modular lab systems and shipped to each expedition vessel where they are installed on deck.

MSCL systems can non-destructively acquire P-wave velocity, density, magnetic susceptibility, electrical resistivity, X-ray fluorescence and color spectrophotometry, as well as total and spectral natural gamma activity. These geophysical measurements are combined with full 3D X-ray CT volume or rapid 2D multi-angle X-ray radiographs to provide a detailed analysis of the cores in advance of destructive logging.

The integration of MSCL and X-ray CT technologies on MARV vessels maximizes scientific output, and its near-real time data feed allows scientists to be reactive to sampling conditions, providing them with an ability to make key scientific or operational decisions in the field – which might not otherwise be possible with conventional coring or logging methods.

SFD-on-deckIn addition to whole core analyses, research objectives often require in-field core processing, description, photographic archiving and sub-sampling. Configuration design of the modular SFD program therefore includes climate-controlled core processing capacity within dedicated modular labs equipped with Geotek’s research-quality core splitting instrumentation, high-resolution Geoscan V cameras, and spacious workspace for visual logging and sub-sampling.

RESEARCH SUPPORTED BY INTERMEDIATE SEAFLOOR CORING

Seafloor coring seeks to answer questions about issues ranging from the dynamics and impact of global climate change, global biogeochemical cycles and geophysics – all of which is supported by deployment of the SFDs. Areas of research focus include:

Bullet1Studies of the Last Glacial Maximum (LGM) using sediment pore waters – This work focuses on reconstruction of the temperature and salinity of bottom waters at the LGM.  Cores that are over 100 meters long are capable of documenting the past history of bottom water variables through their record in pore waters.  This diffusion based problem provides unique information about the past ocean stratification and circulation state, helping us to better understand how the climate moves from glacial to interglacial states.

Bullet1Ocean behavior over many timescales – Movements of mass, heat and carbon in the ocean are an integral part of the dynamics of the ocean-atmosphere system.  Historically sediment cores have provided one of our most important records of past climate change.  Long cores from the SFD allow scientists to reach further back in time than traditional piston coring and to sample past climate change at very high resolution.

Bullet1Deep Biosphere Research – studies microbial communities below the ocean floor to understand the metabolic rates, survival strategies, and influence of these organisms on global biogeochemical cycles. Modular seafloor coring systems and methods have recently contributed important data to this field.

Bullet1Submerged Reefs – prehistoric coral reefs provide, through isotope analysis, archives of tropical climate variability and seasonal/intra-seasonal cycles (e.g. El Niño-Southern Oscillation, ENSO), and provide insights into sea level change and the relative resiliency of reef ecosystems to strong global climate change.

Bullet1Marine Geology and Geophysics – Scientific coring is an important component of research in these fields with applications in understanding the structure, composition, and dynamics of the earth’s crust.

As Global Oceans and Fugro collaborate in mobilizing the SFDs to expand research that is dependent on scientific coring, we look forward to contributing to a greater understanding of our planet’s biological and physical dynamics, its deep past, and the role the oceans play in global climate change.