Geology & Geophysics
The Cauldron Beneath the Seafloor
Just over 20 years ago, scientists exploring the mid-ocean ridge system first made the spectacular discovery of black smokers—hydrothermal chimneys made of metal sulfide minerals that vigorously discharge hot, dark, particulate-laden fluids into the ocean.
Read MoreMid-Atlantic Ridge Volcanic Processes
Long before the plate-tectonic revolution began in the 1960s, scientists envisioned drilling into the ocean crust to investigate Earth’s evolution.
Read MoreIndian Ocean’s Atlantis Bank Yields Deep-Earth Insight
I never imagined I would spend six weeks of my life “wandering around” the seafloor exploring an 11 million year old beach, and it never occurred to me to look for a fossil island. But that’s what I did, and that’s what we found on two research voyages separated by more than a decade.
Read MoreMelt Extraction from the Mantle Beneath Mid-Ocean Ridges
As the oceanic plates move apart at mid-ocean ridges, rocks from Earth’s mantle, far below, rise to fill the void, mostly via slow plastic flow.
Read MoreExploring The Global Mid-Ocean Ridge
There is a natural tendency in scientific investigations for increased specialization. Most important advances are made by narrowing focus and building on the broad foundation of earlier, more general research.
Read MoreDiscovery of “Megamullions” Reveals Gateways Into the Ocean Crust and Upper Mantle
urposes. From the end of the nineteenth into the first half of the twentieth century, drilling was used to penetrate the reef and uppermost volcanic foundation of several oceanic islands, and these glimpses of oceanic geology whetted the scientific community’s appetite for deeper and more complete data.
Read MoreOcean Seismic Network Seafloor Observatories
Our knowledge of the physical characteristics of Earth’s deep interior is based largely on observations of surface vibrations that occur after large earthquakes. Using the same techniques as CAT (Computer Aided Tomography) scans in medical imaging, seismologists can “image” the interior of our planet. But just as medical imaging requires sensors that surround the patient, seismic imaging requires sensors surrounding the earth.
Read MoreA Current Affair
oal of probing the earth’s inaccessible deep interior. But the technique remains something of a mystery even to many marine scientists. It has been used widely on land, particularly for regional-scale surveys, but only a few full-scale MT surveys have been carried out on the seafloor.
Read MoreMarine Snow and Fecal Pellets
Until about 130 years ago, scholars believed that no life could exist in the deep ocean. The abyss was simply too dark and cold to sustain life. The discovery of many animals living in the abyssal environment by Sir Charles Wyville Thompson during HMS Challenger’s 1872-1876 circumnavigation stunned the late 19th century scientific community far more than we can now imagine.
Read MoreExtreme Trapping
One of oceanography’s major challenges is collection of data from extraordinarily difficult environments. For those who use sediments traps, two examples of difficult environments are the deepest oceans and the permanently ice-covered Arctic Basin.
Read MoreThe Rain of Ocean Particles and Earth’s Carbon Cycle
WHOI Phytoplankton photosynthesis has provided Earth’s inhabitants with oxygen since early life began. Without this process the atmosphere would consist of carbon dioxide (CO2) plus a small amount of nitrogen, the atmospheric pressure would be 60 times higher than the air we breathe, and the planet’s air temperatures would hover around 300°C. (Conditions similar to these are found on Earth’s close sibling Venus.
Read MoreDeploying the Rain Catchers
Deployment of a deep-ocean sediment trap mooring begins with the ship heading slowly into the wind.
Read MoreMonsoon Winds and Carbon Cycles in the Arabian Sea
The monsoon, a giant sea breeze between the Asian massif and the Indian Ocean, is one of the most significant natural phenomena that influences the everyday life of more than 60 percent of the world’s population.
Read MoreGround-Truthing the Paleoclimate Record
Sediment Trap Observations Aid Paleoceanographers
The geological record contains a wealth of information about Earth’s past environmental conditions. During its long geological history the planet has experienced changes in climate that are much larger than those recorded during human history; these environmental conditions range from periods when large ice sheets covered much of the northern hemisphere, as recently as 20,000 years ago, to past atmospheric concentrations of greenhouse gases that warmed Earth’s polar regions enough to melt all of the ice caps 50 million years ago. Since human civilization has developed during a fairly short period of unusually mild and stable climate, humans have yet to experience the full range of variability that the planet’s natural systems impose. Thus, the geological record has become an extremely important archive for understanding the range of natural variability in climate, the processes that cause climate change on decadal and longer time scales, and the background variability from which greenhouse warming must be detected
Catching the Rain: Sediment Trap Technology
WHOI Senior Engineer Ken Doherty developed the first sediment trap in the late 1970s for what has come to be known as the WHOI PARFLUX (for “particle flux”) group. Working closely with the scientific community, Doherty has continued to improve sediment traps for two decades, and these WHOI-developed instruments are widely used both nationally and internationally in the particle flux research community.
Read MoreThe Magnetic Thickness of a Recent Submarine Lava Flow
Submarine lava flows and their associated narrow feeder conduits known as dikes constitute the basic building blocks of the upper part of the ocean crust. We are only beginning to understand how lava erupts and forms on the seafloor by flooding topographic lows, flowing through channels or tubes, centralizing into volcanoes, or some combination of all of these.
Read MoreSedimentary Record Yields Several Centuries of Data
Natural climate changes like the Little Ice Age and the Medieval Warm Period are of interest for a few reasons. First, they occur on decade to century time scales, a gray zone in the spectrum of climate change. Accurate instrumental data do not extend back far enough to document the beginning of these events, and historical data are often of questionable accuracy and are not widespread geographically.
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