OCEAN ____________ Chapter 12

 ________ enter the ocean through rivers, glaciers, waves, winds, dissolution of ___________ particles, and chemical reactions.  Once in the ocean _________ are moved through waves, currents, and _________ activity.

___________ STUDY TOOLS AND TECHNIQUES  _________ Sampler – collects a ________ sample of the top sediment  ________ Corer – Hollow _________ pushed into sediment. Used to collect a sequence of _________ layers  ___________ Tools – transmit _________ waves through water and into _________. Used when looking for _____ or natural gas.

Bottom ___________ Grab _______

________ Corer

_____________ – THE STUDY OF SEDIMENT LAYERS  Scientists use deep-sea ___________ to study:  Rock and __________ composition  _________________  Deposition patterns  Based on these they can:  Estimate the age of ______________ layers  Estimate previous ______________ patterns (ancient ocean currents)  Estimate __________ sea levels

_______________ – THE STUDY OF PREHISTORIC OCEANS  From __________ samples we have been able to estimate prehistoric ocean ______________ and climate with accuracy  Research of the Earth’s ancient __________ currently emphasizes deep-ocean ____________ called siliceous oozes  ______________ have played a key role in _______ develop current theories that propose that _______ once had oceans

__________ ORIGINS  1. _____________ sediments – come from ______ erosion or ___________ eruptions  Most common = Quartz, _________, and clay  These are the majority of ___________ found  2. __________ sediments – originate from ___________ and cover a large area of the ___________  Silica and __________ carbonate come from shells and hard skeletons of __________ organisms  2 nd most _____________ sediments found

SEDIMENT ORIGINS  3. _____________ sediments – result from _____________ reactions with seawater  Sources of _________ minerals include submerged rock, new crust formation, ____________ vent water, river runoff  4. ____________ sediments – come from _______ space (tektites)  Cosmic dust and ____________ impacts from asteroids and comets  About 15,000-30,000 metric tons of ________ dust settle on the Earth each year; least ____________ of the sediments

SEDIMENT SIZES  ___________ are classified on grain size – the diameter of the particle  Grain size and current _________ affect the erosion and _________ (moving and settling down) of sediment  Clay & _____ – smallest particles, require high energy to move because they ___________ together  _______ – medium sized, takes the least amount of energy to erode  _______ – larger particles require more energy to erode because they’re heavy.

_____________, TRANSPORTATION, & DEPOSITION  ___________ – very high water speed causes the sediment to float without __________ the bottom (suspension)  _____________ – high water speed moves the sediments by bouncing or _________ along the bottom  ____________ – water speed is too low to move sediments; ___________ are put down

HJULSTROM DIAGRAM  ___________ diagrams are useful for determining if an area is an __________ or depositional environment.  The diagram displays _______ size on the X-axis and water _________ on the Y-axis  The diagram shows the water speed needed to _______, transport, or deposit ___________ of a given size

 Once ________________, sediments on the ocean floor do not move greatly, therefore, older ________ is always on the bottom while younger __________ are deposited on top.  Sediments cover the ____________ topography of the ocean floor, creating the ___________ plains.

OCEAN SEDIMENTS Part 2

SEDIMENTATION ON ____________ SHELF  Waves are the most __________ influence that keep particles from ________

RECENT VS. RELICT SEDIMENTS  Recent __________ – accumulated since the sea level ___________. Found near the beach.  ________ Sediments – accumulated and were left ________ when sea level was lower. Found farther out on the _____________ shelf

CONTINENTAL-SHELF SEDIMENTATION RATES  Main source of ______________ on cont. shelf is from mouths of rivers  _____________ on the shelf is more rapid than in the deep ocean  At the mouths of large rivers, sedimentation can occur at rates of 1 meter per 1000 years  The cont. shelf sediments are primarily ___________ and ____________

SEDIMENTATION PROCESSES ON THE DEEP-OCEAN BOTTOM  Main source of ____________ in deep ocean are the remnants of _____________  Deep ocean sediments are high in ____________ material  ______________ and hydrogenous are rare  Rate of ____________ is VERY ___________  less than 1 cm per 1 ____________ years  Sediments are thickest of __________ plains and thinnest or absent on the mid-ocean ridges and _____________

CONT. SHELF SEDIMENTATION AFFECTS THE DEEP OCEAN  _____________ sediment on the cont. shelf avalanches down the ____________ slopes  Avalanches called __________ currents  Turbidities consist of layers of _____________ sand mixed with the deep-sea _____________

THE CARBONATE COMPENSATION DEPTH (CCD)  ________ is a point at which __________ carbonate dissolves as fast as it accumulates from above  _________ the CCD calcareous (calcium carbonate) ooze dominates  _________ the CCD siliceous (silica) ooze dominates  The slow ____________ of siliceous remains and high plankton productivity allow siliceous _________ to accumulate throughout seafloor.

CCD CONTINUED  CCD varies with region due to ___________ and water __________  Atlantic and ___________ Ocean = 4,500 meter (14,750 feet)  __________ regions – CCD is more shallow – siliceous oozes dominate ____________ sediments in polar regions

_________ PELLETS  Scientists find that ocean floor _____________ is usually similar to particle composition of water above it  This is due to __________ pellets  ___________ consume the calcareous or silicon organisms  They ____________ their waste  The dense fecal pellets ________ quickly and form __________ ooze

MINERAL NODULES  Nodules are _____________ sediments  Ferromanganese _______ = iron and manganese  Found on over ________ of the Pacific floor  ____________ nodules = phosphorite and other trace minerals  Found on the __________ banks and continental shelves  _________ grow at a rate of about 1 – 200 millimeters per million years  Scientists believe that ____________ processes cause the chemical precipitation

____________ & NATURAL GAS  Oil and __________ gas found under the ocean contribute ________________ (that’s billion) dollars in annual revenue  More than ____ of the world’s crude petroleum and ___ of its natural gas come from _____________ deposits on the continental shelf

OTHER ___________ WITH ___________ IMPORTANCE  Ferromanganese and phosphorite nodules have potential _________ value  Mining metal _______ deposits found at deep-sea __________ vents could be ____________ feasible  Sand and ________ are an important resource for the _____________ industry