Glossary
- Advanced Piston Corer (APC)search for term
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The Advanced Piston Corer (APC) is crucial for high-resolution climate and paleoceanographic studies. The APC is a hydraulically actuated piston corer designed to recover relatively undisturbed continuous 9.5 m long oriented core samples from very soft to firm sediments that cannot be recovered well by rotary coring.
- Alkalinitysearch for term
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Alkalinity is measured by titration. An acid of known strength (the titrant) is added to a volume of a treated sample of water. The volume of acid required to bring the sample to a specific pH level reflects the alkalinity of the sample. The pH end point is indicated by a color change. Alkalinity is expressed in units of milligrams per liter (mg/l) of CaCO3 (calcium carbonate).
- Anoxicsearch for term
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A total decrease in the level of oxygen, an extreme form of hypoxia or "low oxygen."
- APCsearch for term
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Stands for Advanced Piston Corer. The APC is a hydraulically actuated piston corer designed to recover relatively undisturbed continuous 9.5 m long oriented core samples from very soft to firm sediments that cannot be recovered well by rotary coring.
- Aquifersearch for term
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An underground layer of water-bearing permeable rock or unconsolidated materials (gravel, sand, or silt) through which water can flow.
- Archive Halfsearch for term
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When a core is split in half, it is the side that is saved and can only be studied without altering it so it can be preserved.
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- Atollsearch for term
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A coral island (or islands) that encircles a lagoon partially or completely.
- Basaltsearch for term
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Basalt is a common extrusive volcanic rock. It is usually gray to black and fine-grained due to rapid cooling of lava at the surface of Earth.
- Basement Rocksearch for term
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The rock layers that lie underneath layers of sediments
- BHAsearch for term
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Stands for Bottom Hole Assembly.
- Bioluminescentsearch for term
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Living organisms, such as algae or fireflies, that can produce visible light.
- Biostratigraphysearch for term
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The study of how fossils are distributed through time and space. These patterns can often be used with other data to date the rock layers.
- Biotic Extinctionsearch for term
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The complete death and disappearance of a life form. This term is more inclusive than the extinction of a species.
- Bridge Decksearch for term
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The bridge deck area, including the helm (steering) and navigation station, is the place from which the Captain and his mates run the ship.
- Calipersearch for term
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Caliper is a tool used for measuring the diameter of a borehole. The measurements are displayed as a caliper log. Open hole caliper logging tools often have four or more arms.
- Catwalksearch for term
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The catwalk is the core receiving platform; it is a covered area outside the Core Lab where each core is handed over to the Lab technicians that clean, measure, and cut it into ~1.5 meter sections.
- Cenomanian-Turonian Boundarysearch for term
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93 million years ago a large Ocean Anoxic Event occurred marking the boundary. At this time the oceans were deprived of oxygen and over 25% of marine invertebrates went extinct. Large charismatic marine reptiles such ichthyosaurs and pliosaurs were also wiped out.
- Chemistrysearch for term
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Chemistry is a physical science that deals with the composition, structure and properties of substances and the transformations they undergo. The JR has a large chemistry lab on the Forecastle Deck.
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- Climate Changesearch for term
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A long-term change in weather patterns
- Contouritessearch for term
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Contourites are the sediments deposited by, or significantly affected by, bottom currents (e.g. Mediterranean Outflow Water in the Gulf of Cádiz)
- Core Barrelsearch for term
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A hollow cylinder used for obtaining cores that is dropped inside the drillstring
- Core Catchersearch for term
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A one-way device that prevents a core from falling out from the inner core barrel once it has entered
- Core Labsearch for term
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Lab designed specifically for the description and analysis of sediment and hard rock cores

- Core Sample Archive Halfsearch for term
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When a core is split in half, it is the side that is saved and can only be studied without altering it so it can be preserved.
- Core Sample Working Halfsearch for term
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When a core is split in half, it is the side that can be tested and studied by scientists.
- CORKsearch for term
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Stands for Circulation Obviation Retrofit Kit. A CORK is a set of scientific instruments designed to monitor conditions beneath the ocean floor.
- Derricksearch for term
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A derrick is a tower that holds the hoisting apparatus for raising and lowering the drilling apparatus on the ship.
- Detritussearch for term
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Small particles, debris, other material worn or broken away from a mass by water or glacial ice
- Downhole Loggingsearch for term
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Lowered instruments down into a drilling hole to collect measurements of the physical properties of rocks and sediments
- Drill Pipesearch for term
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The drill pipe is the pipe that surrounds the core sample and core liner. It has a drill bit at the bottom that drills through the rock to make the core.
- Drill Shacksearch for term
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The drill shack is the room from which drilling operations are controlled.
- Drillstringsearch for term
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The drillstring on The JR is a column, or string, of pipes that transmits drilling fluid (via the mud pumps) and rotational power to the drill bit at the bottom.
- Dropstonesearch for term
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Rock fragments that range in size from small pebbles to boulders. The critical distinguishing feature is that there is evidence that they were not transported by normal water currents, but rather dropped in vertically through the water colum. Dropstones are often carried and deposited by melting icebergs.
- Drydocksearch for term
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To remove a ship from water to a dry basin, typically for repairs
- Dynamic Positioning Systemsearch for term
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Dynamic positioning (DP or DPS) is a computer controlled system that automatically keeps a ship in its position and heading (called “on station”) by using her own propellers and thrusters.

- ELMOsearch for term
- Eocene Layer of Mysterious Originsearch for term
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(ELMO) Period of global warming that occurred approximately 53.7 million years ago (Ma). It appears to be the second major hyperthermal that punctuated the long-term warming trend from the Late Paleocene through the early Eocene (58 to 50 Ma).
- Extended Core Barrel (XCB)search for term
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The Extended Core Barrel (XCB) coring system is used in sedimentological, climate, and paleoceanographic studies.The XCB is used to recover 9.5 m long core samples from soft to moderately hard formations. The XCB is typically deployed when the formation becomes too stiff to piston core (i.e., upon piston coring "refusal") or when it is not hard enough to permit efficient recovery with the Rotary Core Barrel (RCB). The XCB cutting shoe extends ahead of the main bit in soft sediments but retracts into the main bit as the weight on bit increases when firm lithologies are encountered. The XCB uses the same bottom-hole assembly (BHA) as the Advanced Piston Corer (APC).
- Fantailsearch for term
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The fantail is an overhang at the extreme rear of the ship. On The JR, it is the same as the poop deck.
- Forecastle (Foc'sle) Decksearch for term
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A partial deck above the main deck at the bow
- Gabbrosearch for term
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Gabbros are dark igneous rocks formed when liquid magma is trapped under the Earth’s surface and cools there. Large portions of the oceanic crust are made of gabbros.
- Galleysearch for term
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The area of the ship where food and meals are prepared and served
- Gas Hydratessearch for term
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Ice-like minerals that form at the low temperatures and high pressures in the deep sea. These Hydrates contain gases, such as methane, that are trapped within the structure of the hydrate cristals.
- Gas Hydratessearch for term
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Ice-like minerals that form at the low temperatures and high pressures in the deep sea. These Hydrates contain gases, such as methane, that are trapped within the structure of the hydrate cristals.
- Geochemistrysearch for term
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The field of geochemistry involves study of the chemical composition of the Earth and other planets, chemical processes that govern the composition of rocks and soils, and the cycles of matter and energy that transport Earth's chemical components in time and space, and their interaction with the hydrosphere and the atmosphere.
- Geological Layerssearch for term
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Geological layers refer to layers of rocks and sediments with different textures and compositions that are found on land and beneath the ocean floor
- Geologysearch for term
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Geology is the science and study of the history of Earth and its life especially as recorded in rocks and sediments.
- Geophysicssearch for term
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Geophysics is the branch of earth science dealing with physical processes and phenomena the occur on Earth, such as earthquakes.
- Geoscientistssearch for term
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Scientists who study geology, geophysics or geochemistry
- Greenhousesearch for term
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The planet's climate has been fluctuating between two dominant states: the Greenhouse and the Icehouse. These two climate sets generally last for long periods of time (many millions of years) and should not be confused with Ice ages or Glacial and Interglacial periods. A "Greenhouse Earth" or "Hothouse Earth", is a period in which there are no continental glaciers whatsoever on the planet, the levels of carbon dioxide and other greenhouse gases (such as water vapor and methane) are high.
- Greenhouse Conditionssearch for term
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Refers to warm environmental conditions, such as during the early Eocene, when the Polar Regions were free of ice and there were relatively high levels of carbon dioxide in the atmosphere
- Greenhouse Effectsearch for term
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An atmospheric heating phenomenon caused by carbon dioxide, water vapor, methane, and other gases trapping more of Sun’s heat, resulting in higher temperatures on Earth’s surface
- Hold Decksearch for term
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The very bottom deck of the ship, used for storage
- Hotspotsearch for term
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An area of volcanic activity that is found within a tectonic plate and is not caused by a subduction zone. Hawaii, Yellowstone and the Louisville Seamount Trail are all examples of hotspots.
- Hullsearch for term
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The body of a ship that provides buoyancy
- Hydrogeologysearch for term
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The study of water in the Earth's crust
- Hydrogeologysearch for term
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The study of water in the Earth's crust.
- Hyperthermalsearch for term
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Geologically brief time intervals (<200,000 years) of global warming and massive carbon input.
- Icehousesearch for term
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The planet's climate has been fluctuating between two dominant states: the Greenhouse and the Icehouse. These two climate sets generally last for long periods of time (many millions of years) and should not be confused with Ice ages or Glacial and Interglacial periods. An "Icehouse Earth" is a period in which continental ice sheets are present, and wax and wane throughout time known as glacial (ice age) and interglacial periods. During an Icehouse Earth, greenhouse gases tend to be less abundant, and temperatures tend to be cooler globally. The Earth is currently in an icehouse stage - ice sheets are present on both poles.
- Icehouse Conditionssearch for term
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Refers to glacial environmental conditions, such as during the early Oligocene, when the Polar Regions were covered in ice and there were relatively low levels of carbon dioxide in the atmosphere
- Immersion Suitsearch for term
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A special type of waterproof dry suit (also known as a Gumby suit) that protects the wearer from hypothermia from immersion in cold water, after abandoning a sinking or capsized vessel
- Iron Roughnecksearch for term
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The piece of equipment that attaches sections of drill pipe to each other, much like a large, mechanical wrench
- Isotopesearch for term
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Isotopes are atoms of the same element that have the same atomic number (the same number of protons and electrons) but different atomic weights (different numbers of neutrons).
- Jointsearch for term
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On The JR, three 9.5 meter joints of drill pipe are threaded together to make a single stand of pipe.
- K-Pgsearch for term
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The K-Pg, or Cretaceous-Paleogene boundary, marks the mass extinction event 65.5 million years ago that is most famous for killing the dinosaurs.
- Lab stacksearch for term
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The multi-floor area of the ship that houses all the scientific laboratories on board the ship
- Lithospheresearch for term
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The outermost shell of the Earth that includes the crust and the uppermost portion of the mantle. The lithosphere is rigid, yet able to bend, move, fracture and break into tectonic plates.
- Loggingsearch for term
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Lowering instruments down into a drilling hole to collect measurements of the physical properties of rocks and sediments
- Logging Scientistsearch for term
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A person who analyzes data from logging instruments – those lowered down into a drilling hole to collect measurements of the physical properties of rocks and sediments.
- Main Decksearch for term
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The highest deck of the hull, usually but not always the weather deck
- Marine Biologysearch for term
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Marine biology is the scientific study of living organisms in the ocean or other marine or brackish bodies of water.
- Marine Geophysicssearch for term
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Geology that deals with the physics of the ocean, including seismology, volcanology, and geomagnetism
- Mbrfsearch for term
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Meters Below Rig Floor or MBRF adds the vertical distance between the water line and the rig floor to Meters Below Sea Level or MBSL. The height of the rig floor above the water line changes as we use fuel, pump ballast, take on supplies, etc.
- Mbsfsearch for term
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Meters drilled or logged below seafloor.
- MECOsearch for term
- Mediterranean Outflow Watersearch for term
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The Mediterranean Outflow Water (MOW) corresponds to the water flow coming from the Mediterranean Sea into the Gulf of Cadiz through the Straits of Gibraltar.
- Middle Eocene Climatic Optimumsearch for term
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After the PETM the Eocene climate went through a period of general cooling with a series of hyperthermals. The Middle Eocene Climatic Optimum (MECO) occurred42 million years ago a sharp increase in carbon dioxide caused a warming trend that lasted about 600,000 years..
- Moon Poolsearch for term
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A moon pool is an opening in the floor of the ship, giving access to the water below, allowing technicians or researchers to lower tools and instruments into the sea.
- MOWsearch for term
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Stands for Mediterranean Outflow Water.
- OAEsearch for term
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See Ocean Anoxic Event.
- Ocean Anoxic Eventsearch for term
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Also known as an OAE, it is an event where the oceans become completely depleated of oxygen. OAEs have happened many times in the past and are often associated with mass extinction events.
- Oceanic Circulationsearch for term
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The circulation of large-scale ocean currents that is driven by differences in the density of seawater at different locations. The density of seawater changes depending on how much surface heat and freshwater it receives.
- Oligocene-Miocene Boundarysearch for term
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Occured 23 million years ago. It is not set at an easily identified worldwide event but rather at regional boundaries between the warmer late Oligocene and the relatively cooler Miocene.
- OsmoSamplersearch for term
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A device consisting of an osmotic pump connected to a long section of small-bore tubing used to collect water samples
- Paleclimatologysearch for term
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Paleoclimatology is the study of climate change taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, and rocks to determine what climate was like in the past.
- Paleo Combosearch for term
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The Paleo Combo is a downhole logging tool that measures the natural gamma radiation, density, and magnetic susceptability (amount of magnetic material) in the sediment.
- Paleocene-Eocene Thermal Maximumsearch for term
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Also called the PETM, the Paleocene-Eocene Thermal Maximum was a super-warm climate event that occured 55 million years ago. During this time, the Earth released massive amounts of greenhouse gasses and temperatures rose to the highest levels in the last 80 million years. During the PETM there was no ice on Earth. It was so warm that the poles were covered in cyprus swamps and redwood forests. The PETM is also characterized by a mass extinction of foraminifera in the deep sea.
- Paleomagnetismsearch for term
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Paleomagnetism is the study of the record of the Earth's magnetic field preserved in various magnetic minerals through time.
- Paleontologysearch for term
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Paleontology is the study of the history of life on Earth, as reflected in the fossil record.
- Peer Reviewsearch for term
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The evaluation of a scientist’s work, usually in the form of a paper, by other scientists to ensure good science has been conducted
- PETMsearch for term
- Petrophysicssearch for term
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Petrophysics is the study of the physical and chemical properties that describe the occurrence and behavior of rocks, soils and fluids.
- Physical Propertiessearch for term
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Physical properties describe the physical characteristics of rocks and sediments such as appearance, texture, color, odor, density, solubility, porosity, magnetic, and other properties of rocks and sediments. The JR has many physical properties instruments housed in the core lab.
- Physical Sciencessearch for term
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Physical science is an encompassing term for the branches of natural science that explore non-living systems, in contrast to the biological sciences.
- Poop decksearch for term
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The poop deck is a partial deck above a ship’s main afterdeck (toward the back of the ship).
- RCBsearch for term
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Stands for Rotary Core Barrel. The RCB is a rotary coring system designed to recover core samples from firm to hard sediments and igneous basement.
- Reentry Conesearch for term
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The Reentry Cone and Casing (RECC) system is a permanent seafloor installation (or legacy hole) that helps scientists return to and re-enter a particular hole.
- Rhyzon samplerssearch for term
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Rhyzon samplers are soil moisture probes that enable discrete sampling with minimal disturbance to the sediment surface. The method does not require filtering or removal of wet sediment from the piston core.
- Rotary Core Barrel (RCB)search for term
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The Rotary Core Barrel (RCB) is a rotary coring system designed to recover core samples from firm to hard sediments and igneous basement. The RCB is crucial for oceanic crustal hard rock studies.
- Salinitysearch for term
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The amount of salt in seawater, usually measured in parts per thousand
- Seamountsearch for term
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A mountain in the sea that is at least 100 meters high and is not found on a continental shelf.
- Sediment Driftsearch for term
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Sediment, such as sand, mud, silt, and clay, carried and deposited by deep ocean currents.
- Sedimentologysearch for term
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Sedimentology is the study of sediments such as sand, mud (silt), and clay, and understanding the processes that deposit them. Sand, silt, and clay are defined according to their grain sizes, with sand composed of coarser grains and clay composed of finer grains.
- Seismic Explorationsearch for term
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Seismic exploration is the search for geologic resources such as crude oil, natural gas, and minerals by using sound waves to produce images of the rock layers below Earth’s surface. Seismic maps are helpful in determining the best places to drill.
- Seismic reflectionsearch for term
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Seismic reflection is a method of geophysical exploration that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as an "air gun".
- Splicesearch for term
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The splice is a composite core section representing the best available representation of a complete stratigraphic column at a site. It is composed of core sections from adjacent holes such that coring gaps in one hole are filled with core from an adjacent hole.
- Stratified Watersearch for term
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Water stratification occurs when water with different salinity (halocline) and/or temperatures (thermocline) form a barrier because their properties prevent them from mixing.
- Stratigraphic Correlationsearch for term
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The process of taking observed and recorded data on multiple cores, and using the similarities to create a composite view of the area sampled. Because of the wiggle in data from multiple holes, this is sometimes called "Wiggle Watching".
- Survival Suitsearch for term
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A survival suit (or more specifically an immersion survival suit), is a special type of waterproof dry suit that protects the wearer from hypothermia from immersion in cold water, after abandoning a sinking or capsized vessel.

- Thermistorsearch for term
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A temperature-sensitive resistor used to measure temperature
- Thrusterssearch for term
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A thruster is a small (relatively) propulsive device used by a ship to keep it in a particular position. The JR has 12 thrusters that are controlled by the Dynamic Positioning System.
- Time Series Analysissearch for term
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Time series analysis is the study and interpretation of data taken at equally spaced time intervals.
- Tripping pipesearch for term
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“Tripping” simply means raising or lowering the drill string
- Turbiditessearch for term
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A sedimentary deposit formed by a turbidity current.
- Turbidity currentssearch for term
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Turbidity currents can be set into motion when mud and sand on the continental shelf are loosened by earthquakes, collapsing slopes, and other geological disturbances. The turbid water then rushes downward like an avalanche, picking up sediment and increasing in speed as it flows.
- Tween Decksearch for term
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These are smaller storage levels/partial decks within the hold deck. The JR has an upper and a lower tween.
- Vertical Seismic Profile (VSP)search for term
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A VSP differs from a conventional reflection profile in that the receiver is clamped successively at different borehole depths within the Earth.
- Weatheringsearch for term
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The breaking down of rocks, soils, and minerals through contact with the Earth's atmosphere, biota and waters.
- Working Halfsearch for term
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When a core is split in half, it is the side that can be tested and studied by scientists.
- XCBsearch for term
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Stands for Extended Core Barrel. The XCB is used to recover 9.5 m long core samples from soft to moderately hard formations.
