GEOPHONE . A transducer used in seismic work. When 

 it is placed in the ground it responds to any dis- 

 placements of the ground caused by the passage of 

 elastic waves arising from earthquakes, seismic 

 shots, explosions, etc. 



GEOPHYSICS. The study of the physical character- 

 istics and properties of the Earth. (27) 



GEOPOTENTIAL . The potential energy of a unit mass 

 relative to sea level, numerically equal to the 

 work that would be done in lifting the unit mass 

 from sea level to 'the height at which the mass is 

 located; commonly expressed in terms of dynamic 

 height or geopotential height. The geopotential 

 S at height z is given mathematically by the 

 expression, 



gdz. 



■1 



where g is the acceleration of gravity. (24) 



GEOSPHERE . The "solid" portion of the earth, in- 

 cluding water masses; the LITHOSPHERE plus the 

 HYDROSPHERE. 



Above the geosphere lies the ATMOSPHERE and 

 at the interface between these two regions is 

 found almost all of the BIOSPHERE, or zone of life. 

 (12) 



GEOSTROPHIC . Referring to the balance, in the at- 

 mosphere, between the horizontal coriolis forces 

 and the horizontal pressure forces. (24) 



GEOSTROPHIC WIND . A wind that blows parallel to 

 straight isobars, with no tendency to curve, 

 because of a balance of forces. These forces are 

 the pressure force (high to low) and Coriolis 

 (apparent deflecting force due to the rotation of 

 the earth). Such a wind blows along a great circle. 

 A GRADIENT WIND blows parallel to curved isobars . 

 (17) 



GEOSYNCLINE . An elongated trough in which sedi- 

 ments accumulate to considerable thickness (up to 

 40,000 ft.) where they are available from neigh- 

 bouring land masses by erosion. Such geosynclinal 

 areas, for example the southern North Sea, have a 

 tendency to prolonged subsidence. (27) 



GFCI . Gulf and Caribbean Fisheries Institute. 



GFCM. General Fisheries Council for the Mediter- 



GHARBI , A fresh westerly wind of oceanic origin 

 in Morocco. (12) 



GIANT FLOE . See FLOE. 



GLACIAL DRIFT (GLACIAL ALLUVIUM) . Rock debris 

 which has been transported by glaciers and deposit- 

 ed either in place as the ice melts, or carried 

 some distance by accompanying melt water before 

 deposition. (27) 



GLACIER . A mass of land ice, formed by the further 

 recrystallization of FIRN, flowing slowly (at pres- 

 ent or in the past) from an accumulation area to an 

 area of ablation. 



This term covers all such ice accumulations 

 from the extensive continental glaciers of prehis- 

 toric ice ages, to tiny snowdrift glaciers. Nearly 

 all glaciers are classified according to the topo- 

 graphical features with which they are associated, 

 for example, highland glacier, plateau glacier, 

 piedmont glacier, valley glacier, cirque glacier. 

 They are also classed according to their seasonal 

 temperatures, or melting characteristics as tem- 

 perate glaciers, or polar glaciers. If a glacier 

 is flowing it is active or living; but an active 

 glacier may be advancing or retreating depending 

 upon the rate of flow compared to the rate of abla- 



tion at the terminus. A glacier which has ceased 

 to flow is termed stagnant or dead . (12) 



GLACIER ICE . Any ice that is or was once a part of 

 a GLACIER. It has been consolidated from FIRN by 

 further melting and refreezing, and by static pres- 

 sure. Glacier ice may be found in the sea as an 

 ICEBERG. (12) 



GLACIER ICEBERG . An iceberg derived from a glacier, 

 piedmont ice, or confluent ice. It is usually much 

 smaller than a tabular iceberg and is bluish or 

 greenish in color, with little or no snow covering. 

 It often contains many crevasses. (17) 



GLACIER TONGUE . See ICE TONGUE. 



GLACIO-EUSTATISM . See EUSTATISM. 



GLACON. A fragment of SEA ICE ranging in size from 

 BRASH to a MEDIUM FLOE. (25) 



GLASS-RANGES OF PROPERTIES . 

 Specific Gravity 

 Specific Heat (cal/gm - °C) 

 Thermal Conductivity 



(cal/sec-cm -°C) 

 Coefficient of Expansion 



(10-7/°C) 

 Refractive Index 

 Photoelastic Fringe Constant 



(5461 A) 

 Light Transmission 

 Dielectric Constant 

 Dielectric Strength 



(volts/mil) (0."25) 

 Volume Resistivity (ohm-cm) 

 Poissons Ratio 

 Young's Modulus of Elasticity 



(10° psi) 

 Compressive Yield Stress 



(10^ psi) 

 Flexural Strengths (treated) 



(psi) experimental 



guaranteed minimum 

 Delayed Elastic Recovery 



(% of unit strain) 

 Creep After 10 Years at 



200,000 psi 

 Creep After 168 Hours at 



800,000 psi 

 Maximum Temp, for No Creep 



(500 hrs.) (°C) 

 Anneal Point (°C) 

 Softening Point (°C) 

 Working Point (°C) 

 Toxicity 



2.18 and up 

 0.17 



0.0025 



8 to 127 

 1.47 and up 



1150 lbs/in. order 

 up to 90% 

 3 . 8 and up 



17 



250 



10^2 to 10 



0.18 to 0.24 



8 to 17 



0.8 to 1.25 



120,000 

 35,000 



0.5 



330 to 710 

 350 to 1200 

 400 to 1500 

 750 to 1700 



GLIMMER ICE . Newly-formed Ice within CRACKS or 

 holes of older ice, or in the puddles upon older 

 ice. (25) 



GLITTER . The spots of light reflected from a point 

 source by the surface of the sea. Statistical 

 analysis of glitter patterns has revealed relation- 

 ships from which the roughness of the sea can be 

 determined by the study of photographs of the 

 glitter. (12) 



GLOBAL SEA . The concept of all of the sea-waters 

 of the earth as being but parts of one global 

 ocean, constantly intermixing. (27) 



GLOBIGERINA . A very small marine animal of the 

 foraminifera order, with a chambered shell; or the 

 shell of such an animal. In large areas of the 

 ocean the calcareous shells of these animals are 

 very numerous, being the principal constituent of 

 a soft mud or globigerina ooze forming the ocean 

 bed. (17) 



GLOBIGERINA OOZE . See GLOBIGERINA. 



GMT. See GREENWICH MEAN TIME. 



52 



