THE MARINE ENVIRONMENT

SEC. 20.1.1 - PHYSICAL OCEANOGRAPHY

SEC. 20.1.2 - MARINE CHEMISTRY

SEC. 20.1 . 3 - MARINE GEOLOGY ,

by

Pat Wilde

From

S o c i e t y o f Mining Engineers:

Mining Engineering Handbook Vol. I1

A. B. Cummins and I . A. Givens: Ed i to r s

COMMITTEE ON O C E A N . ENGINEERING COLLEGE Of ENGINEERING

UNIVER S I T Y OF CAL IFORNlA

B E R K E L E Y

i .

f 20.1.1-PHYSICAL OCEANOGRAPHY . .

. . . i PAT WILDE

1 The findnmentnl parameters measuryd in pl~ysicd occnnogrnphy are: (1) three-

< SME . ' 1 dimensional position, (2) tempernture nnd (3) salinity (more exnctly, conductivity). Otlier important pnmmetcn, such ns pressrlre, density, wntcr particle velocity, sound velocity and light transmittnnce are a t lcnst in part derived from the funda-

Mining Engineering . : 1 mental -

Three-Dimensional Position . . North-South-Parallels of latitude-degrees, minutes and seconds of arc, assuming

. . the eauator RS 0' with the North Pole 90°N and the South Pole 90"s: 1" latitude is . -... ~

Handbook I . . 1 approkmately equal 60 nautical mi; therefore 1 min latitude S 1 nautical mi, E 6,080

. . it, and 1 marine lengue = 3 nautical mi.

. . . . . . . I . i TABLE 2O-1-Area. Volume and Mean Depth of t h e Oceans (Menard and Smith')

I 1 7 1 Two Volumes Mean Depth.

' ' Volume 2

. . . . . . . . . ' . . . . . , . .,

. . . *. '. . * , , . . . , . . :

_ARTHUR B. CUMMINS - . . . . .I G

' I . . . . i ,

.- , . . ,

' ' Chairman, Editorial Board . ' i

. . . : . . . . ,~ . . . . ' . 2

. . . . . . . _ Editor . . . : . . . . : .. . . t

. . ! ' , - , . , ... . . . . . . . . . . . . . . . . . :: Sponsored by . i . . . .

, . . Seeley JV. Rludd Memorial Fund of AIhlE I . . Society of, Mining Engineers of AIME . . '

. ... . . U.S. Bureau of hIincs, Dept. of tile Interior , . :.. ' , , . , ' ,: ,.:

. . . . . . . . . .

. . . .

. , , a ', ..: ',..: ,.,, :- , < . ' 1 . 1 , . , . . . I . .

,, _ .,,.,,: ',.., Society of Mining Engineers . . . . . . . . . . of

The American Institute of Mining, ~ e t a l l u r ~ i c a l , and Petroleum Engineers, Inc. ' I . . . . ' , . c . .. . .:,, New York, New York - -- \ . . . . . ,,<< ;\:.72,i . . . . . . . . . .

1073 . . . . .

m, . . '

' Area, Volume, Menard and . ' Oceans and Adjacent Seas : 10gSq Km lo,# Cu Km Smith

....................................... Pacific 166.241 Asiatic Mediterranean.. ..................... 9.082 Bering Sen.. ............ , ............. ! ..... 2.261 Sea of Okhotsk.. ........................... 1.392 Yellow and East China sens.. ................ 1.202 Sen of Jnpnn.. ............................. 1 .O13

......................... Gulf of California.. 0.153 Pacific and adjacent seas, total.. .............. 181.344

..................................... Atlantic. 86.557 American Mediterranean.. .................: 4.357 Mediterranenn. ............................ .2.510 Black Sea.. ................................ 0.508 Bdtic Sea.. ............................ i .. 0.382 Atlantic and adjacent seas, totnl.. ............ 94.314

.................................... Indian.. 73.427 Red Sea.. ................................. 0.453 Persian Gulf.. ............... : ............. 0.238 Indinn and ndjncent seas, total.. ............. 74.118

........................................ Artic 9.485 Arctic Mediterrnnean.. ..................... 2.772 Arctic and adjacent seas, total.. ............. 12.257

Totals and mean depths.. ................. 362.033

I East-West-Meridians of longitude--degrees, minutes, seconds of arc assuming Greenwich, England, ns 0" or the prime meridian (French charts often use Paris as the prime meridinn) ; meridinna e ~ s t of prime meridinns to 180" are east longi- tude; meridians west of prime rneridlan to 180" nrc west longitude.

VerlicnGDeptli in linear units-fathoms, feet, meters, (US. now only major country that uses fatlloms for depth measlire), datum sea surfnee. One fathom = 6 f t = 1.8288 m. Echo sounding depth recorders rending (1) in fathoms nssume a ' speed of sound in seawater of SO0 fathoms (1,463 m) per sec, (2) in meters, 1,500 (820 fnthoms) per sec. Corrections for variations of the speed of souild in seawater nre given in Matthews Tnbles' for the ocenn divided into 46 regions. The area, volume nnd depth of the world's oceans and seas nre listed in Table 20-1.

Temperatura 'Centigrnde (Celsius), "Fnhrenheit. "Fahrenheit = 9/5"C + 32. Temperature is

mensurcd by (1) substances with a, lincnr cocficient of thermal expansion (mercury thermometer), (2) temperature-sensitive resistor (resistance thermometer or thermistor), (3) a crystnl whose oscillation ircquency is temperature dependent

T e m p

*i"

MAIN /THE;;ElME

LOW M I D HIGH LAT I T U D E S LAT ITUDES. LATITUDES

.,

Flg. 20-1-Typical mean temperature profiles in the open ocean (Pickard').

S o l i n i t y %O

33 34 35 36 37 33 34 35 36 33 34 35 36 37

1000 - 1 M I D

' LAT. MID C LAT. C

2000- n - 5 00 0)

D TROPICS

3000 -

r

40001 4 000- . . -

Salinity 0/00, parts per thousand, ppt. Classically done by nrgentometric titration of

the chlorinity (CL) (total halogens). Total dissolved solids (ppt) = 0.073 + 1.811 CL (ppt), although salinity (ppt) = 0.03 + 1.805 CL (ppt). Approximnte &qlinity detcrminat.ions can bc mnde by titrating 10 cu cm of senwater with n solu- tion bf 27.25 g per 1. The volume of AgNOs solution required in cubic

approximates the salinity (ppt) (Harvey').

; tlg. 20->Extinction coefficient (a) for light beam in pure water as a function of its wave ATLANTIC PACIFIC 1 length, I-m thickness of layer (Dietrich7).

t t Fig. 20-~-T~picnl mean snlinity profiles in the open ocean (Pickard').

(quartz thermometer) nnd (4) by infrared emissions (rndintion thermometer or bolometer).

Tcmpcrnture profiles in thc occan (Fig. 20-1) t.ypicnlly show a threefold zonntion: (1) n surface isotllcrmal mixed layer of Ilighcr tcmperntures, (2) n transition zone of dccrcnsing tcmpernture cnlled the thcrmoclinc, nnd (3) n deep rclatively isother- mnl zonc of lo\rest tcmpcratures. In gcncrd, tempcrnturc profilcs are stnble; that is, wnrmcr wntcr overlies colder wnter. Thc nvcrngc tcmpernture of seawater is about 4°C.

Most modern measurements are made conductametrically with an induction salinorneter where salinity (ppt) = 18OG55 CL (Cox'). Salinity profiles in the oceans genernlly look like tempcrnture profilcs. However, mnny exceptions are found. The vertical salinity distribution usually is unstable ns higher snlinity wnter due to evaporntion nt the surface overlies lower salinity water a t depth. The nverngc salinity of the oceans is about 35 ppt.

Pressure-Atmosphere = 1.01325 x 10' dynes per sq c m ; bnr = 0.98692 ntmo- spheres = 1 x lod dynes pcr sq cm; dccibnr = 0.1 bars. As the depth in the ocenn m meters is npproximntely numerically equal to the pressure in decibars, most

pressure values nre derived from depth mensurementa. However, pressure eensom also are used to measure depth in in-situ real-time remote probes.

Den~ity-~ = g per cu cm ; us.^,,. = (ps,~,p-l) 1,000. Density is a function .of salinity, temperature and pressure. Tables of in-situ density are bnsed on deviations from the stnndsrd ocean where the salinity = 35 ppt, temperature =O°C, nnd pressure = 1 atm (Xundsen8). The inverse of density, specific volume, @, often is used. The specific volume nnomnly, thus, is 8 = ~ S , T , P - ~ ~ s , o , I . The average density of the ocenns is about 1.025 g per cu cm, or u = 25.

Optical Propertiedndez of ~ejraction-A function of salinity and temperature, o r so.rro = 1.332497 + 0.000334 CL (ppt).

Absorption-In seawater with little pnrticulate matter the coefficient of absorp- tion is similar to pure water (Fig. 20-3) with tlie major nbsorption towards the

Flg. 20-4-a, velocity of sound V (in meters per sec.) in seawater as a function of ternpera- ture nnd salinity, neglecting pressure; b, a t different depths a t a temperature of O°C and a salinity of 35 % as a function of pressure (a and b after S. Kuwahara, 1938) (Dietrich').

red end of the spectrum. This is why most objects in seawater illuminated wih sunlight have a bluish cast.

Color-The color of seawater for clear skies with the optical center of incident light s t 0.47~ is (1) blue for clear open-ocean water where extinction is due to absorptive properties alone (see Fig. 20-3) ; (2) blue-green to green with the addition of organic particles, for example, near a cord reef; (3) yellow in rcgions of high humic content near major rivers, (4) chocolate-brown off coastal regions delivering silts and clays so that the sea color is due partially to light reflection off individunl particles, and (5) green, brown or red for high concentrations of plankton, as in red-tide blooms.

Acoustlc Properties-The velocity of propagation of sound wnves in the ocean can .- I . dl be appmrimnted by V --, where r = the adiabatic compressibility, a function [

of temperature and pressure ' ( ~ i g . 20-4),,

I

Tlie combination of a stepwise incrcase in the temperature profile nnd the ]incar increase in pressure with depth produces sound velocity profiles as shown in Fig. 20-5, which generally have velocity maxima nenr 1,000 m.

Circulation Surface-Fig. 20-6 shows the major s~rrface currents of the world ocean. The

basic circulation pattern is gyroidnl, clockwise in the northern hcmisphcrc due 10 the right-hnndcd Coriolis deflection and countcrclock~visc in the so~~thcrn 1,crnisphere ~vliere the Coriolis deflection is left-hanclcd. The western boundary c,rrrent~, such as the Gulf Stream nnd the Japan Current, are the swiftest, ngsin ' [ ~ e to. the rotation of the earth. An exception is in the South Pacific, where the Peru Current on the east boundary is the strongest, presumably due to the pileup of water in the Drake Passage between Antarctica and South America in the West Wind Drift.

Fig. 20-5-Examples of horizontal velocity of sound in the world ocean (Dietrich7).

Deep-The deep circulation of the oceans is monitored by tracing water masses, which are relatively homogeneous packets of water which move essentinlly along density surfaces horizontally from their place of formation. Tnble 20-2 lists some

. ,

of the major water misses.'The geographic prefix usunlly refers to the site of formation. Most of the deep-water characteristics of the oceans are produced in the winter,jn high latitudes where cold temperntures and freezing ice tend to mnke the water cold and more saline, thus more dense. This denser water flows toward the equator under less dense surface water, driving the oceanic cil.culntion, and imparts a polar character to the deep and bottom waters of the world occan.

Kinetics-The driving force for the movement of seawater npparently is the ~ f f cc t of solar insulation on seawater on the rotating earth. Nenr shore, there Is the additionnl tidal effect of the sun-moon system. According to Ekmnn,'Ql~ere are three major hydraulic regimes in the ocenns: (1) a surface region where wind- driven frictional forces predominate, (2) nn intermediate zone where rot.ntionnl forces predominnte and (3) n lowcr region nenr the bottom where frictional drag forces predominate. Nenr shore, the upper and lower zones merge. In tlic deep

TABLE 20-2-Water Masses of tho Ocean (Defanto)

Temp., Salinity. Temp., Salinity, North Atlantic OC South Atlantic OC

1 , North Polar 1. Central water.. +5 t o $10 34.3-35.6 watcr.. . . . . . . . -1 to +2 34.0 2. Antarctic inter-

2. Subarctic water, . +3 to $5 34.7-34.9 mediate water +3 to +5 34.1-34.6 .. 3. Central water.. +4 to +17 35.1-36, 2 3. Subantarctic ..... .... 4. Deep water.. 4-3 to $4 34.9-35.0 water.. $3 to +9 33.8-34.5 .. 6. Bottom water.. + 1 to 4-3 34.8-34.9 4. Antarctic cir-

0. Mediterranean cum-polar water.. ....... 4-6 to +10 35.3-30.4 water. ...... t 0 . 5 to +2.5 34.7-34.8

6. Deep and bot- .. tomwater . O t o + 2 34.6-34.9

6. Antarctic bot- . tom water.. - 0.4 34.66

Waler Masscs of the Indian Ocean

Temp., OC Salinity, %Q

............... 1. Equatorial water.. 4-16 34.8-35.2 2. Indian central water.. ............ 6-15 34.E-35.4 3. Antarctic intermediate water.. .... 2-6 34 .434 .7 4. Subantarctic water.. ............. 2-8 34.1-34.6 6. Indian Ocean deep and antarctic

circumpolar water.. ............ 0.5-2 34.7-34.75 6. Red Sea water.. ................. 9 35.5

Water Masses of the Pacific Ocean

North Pacific Temp., I OC

Snlinity, %9 South Pacific

. . 1. Subarctic water. . 2-10 2. Equatorial water.. . 6-16 3. Eastern North

. . Pacific water.. ,. 10-16 4. Western North

.... Pacific wnter. 7-16 6. Arctic Intermediate

water ........... 6-10 6. Pacific deep wnter

and Arctic cir- cumpolar water. . ( - 1)-3

1. Eastern South Pacific water.. .... 9-16

2. Western South Pacific water.. .. 7-16

3. Antarctic interme- diate water. .... 4-7

4. Subantarctic water 3-7 5. Pacific deep water

and Antarctic circumpolar water.. ........ (-1)-3

Flg. 20-6-Tho surface currcnts of the oceans. The pattern of wres (clockwise in the . ocean, however, the nonfriction or eeostroohic (earth-turned) forces determino Northcrn IIemisphere and counterclockwise in the Southern) can be explained as a result of global wind pntterns-the prevxiling westerlies blowing from west to east a t nbout f the water moveme, 40°N and 40°S and the trnde winds blowing from east to west just north and south of Frictionless Flow the Equator (from "Tho Circulation of the Oceans," Walter h lunk l~ ) . Copyright 1955 by

Geoatrophic Eqwl Sn'enlific American, Inc. All rights reserved. a dP

where c - geostrophic velocity (oriented perpendicular to the direction of N-from high Dressure to low pressure-and (a) to the right of N in the Northern Hemisphere (b) to the

lelt of N in the Southern Hemisphere): a m specific volume - 1 per density; f = geo. a n '. " L~

strophic parameter = 20 sin 4; o = rotation earth; I$ - geographic latitude; - a N pressure gradient. . . .

8 . . Gradient Equation-For sloping isobaric surfaces, I

. . .- g tan 0 max j

c - . ,

f r where tan 0 5 slope of isobars. (, . .. - . .

Margules Equation-Where a lighter water mass overridcs a dcnscr, . . .. , . . . .

. . i . . .

f (po - PIC') tan y - - g (P' - PI

where y = slope of interface between two water masses, p = density of lighter water, c = geostrophic vclocity in lighter wnter, p' = density of heavier wnter, c' =. geostrophic vclocity in heavier water.

Hella,nd-Hansen Equation-To determine rclative velocities between two stations, knowing temperature and salinity profiles at each station: . -.

mhere CI = geostrophic velocity at'givon depth, co = geostrophio velocity at reference depth, AB = distance betwecn stations, PI - pressure at given depth, Po pressure at rcference depth, cue = specific volume Station B, a* = specific volume Station A

See Formin" for details. Friction Flow .

Wind-Generated Currents-At the sea surfnce empirically (Dietrich') . .

XW vo = - (Sin 4)M

mhere Vo = surface currcnt velocity; W = wind velocity, X = constant = 0.0126 if W in cm per sec, c = geographic Intitude.

Munk" believes that 700 cm per sec is the threshold velocity to initiate minddrift currents.

The decay of wind-generated currents with depth is given by E h a n M ae

- TZ V = V o e - , D = r V A,

D pw Sin (6

where V = velocity a t some depth e, Vo = surface current velocity, A. = eddy ; viscosity, p = density.

If z = D, Velocity V is directed 180" from the surface velocity, Vo, so, for pmcticd purposes, wind frictional effects cease. The depth where z = D is called , the depth of frictionnl resistance. I3eneath this zone the Row sho~ild be geostrophic.

Waves-As L = cT, wherc L = mave length, c = phase vclocity nnd T = wave period. Assuming linear theory, the rclntionships among mave vclocity, wave period, mave length and water depth are given by

I . . I i

where d = water depth. I For deep water, d/L > j5, practically, ' 1 .

For shallow water, d / L < 1/25, practicnlly, c = (gd)H (Wiegcl"). I

THE MARINE ENVIRONMENT 20-11

Tides-The interaction of the gravitational fields of the enrth, moon and sun product the periodic rise and fnll of the oceans called the tides. The average

. intervnl between two high or two low tides is 12:25 hr, or one-half a lunar pnssoge. Diurnal and semidiurnnl deviations from the lunnr time nre caused by the sun's ficld. Nenr new and full moon, the moon-sun fields reinforce each other to produce mnximum high and low water, called spring tides. Near the first and third quarter

2 r Imminghom: semi diurnal type, f :O+I

1 San Fronciso: mixed,hinont seml diurnal type, Fr0.90 -I

Monib: mixed. dan im full dunol type. F= 2.15

b S m full diurnal type, f * 18.9 . . , . . . . :-. .

. . ; ..-..

l l g . 20-7-Tidc curves for March 1930 phases of the moon. N and S are the largest north- ern and southern declination of the moon; Q, passage of the moon through thc Equntor (Defant*).

moon, the fields are in opposition, producing a minimum tidnl rnnge, called nenp tides. Modifications of the ideal tidnl cycles are caused by the configuration of thc sea bottom nnd thc constlinc, nnd thus are pnrticulnr to the locale. Fig. 20-7 8h0ws some representntive tides.

Where geograplrical frictional effects on tlre tidal cycle arc lnrgc, for cxnmple, . in eomplcx estuaries, u pnrticulnr tide is not repented for 18.6 yr, \\*lien tlic sua-n~oon

return to n given porition. Thus, 10 years of record nre neceanry to completely describe tidnl fluctuntions.

, , . .: ' . . . , . . . . 20.1.2-MARINE CHEMISTRY I . ..

Composition Major Ions-Seawater is not simply evapornted river water, as the ions in

each are in different proportions. Unlike river wnter, which may have n variable dissolved ionic content, seawater hns the property thnt the major dissolved ions are in relatively constant proportion to each other (Dittmar"). I3y determining the concentrntion of one ion the others may be computed. Tnble 2 0 3 gives the

TABLE 20-3-ton-Chlorlnlty Relatlonshlps of the Major Ions In Sea- water (CI, B. F: Sverdrup and others;ld Na, K. Mg, Ca, Sr, Culkln and

COX;^' Br, SO,, Morrls and Rileyl')

Ion Concentration, G per kg

Sr* = 0.0004 CL Br- = 0.003473 CL " B- = 0.00023 CL F p: 0.00007 CL

Sod' 3 0.1400 CL

TABLE 20-4-A Recipe for Artiflclal Seawater (Lyman and Flemlngla)

NnCI ........................... 23.477 NaHCO: ......................... 0.192 MgClr .......................... 4.981 KBr ............................. 0.096 NnlSOa.. ....................... 3.917 IIsBO: ........................... 0.026 CnClr.. ........................ 1.102 SrCIr. ............................ 0.024 KC1 ............................ O.GG4 NaF ............................ 0.003

H10 to 1,000 g; allow for water of hydration to produce water of CL = 19 ppt.

senwnter relationships in terms of chlorinity, the most commonly determined pnram- eter. The concentrntions of 60 elements in seawater is givcn i p Sec. 20.1.4 (Tnble 20-17).

Tnble 20-4 shows a recipe for artificial seamnter (Lyman and Flemingu). T~ace low-Trnce metals do not show the constancy of proportion of the

mnjor ions (Tnble 20-5) bu t vary midcly in concentration. Other Parameters

pH-pH, or -log[Ht1, of seawater u s ~ ~ d l y is mensured with glnss electrodes. Surface values average about 8.1 with n minimum value of nbout 7.6, corresponding t o the depth of the oxygen minimum (Fig. 20-8). Thus, the senwntcr is slightly nlknline throughout the entire verticnl column.

Alkalinity-4cnwatcr is a good pH buffer. Therefore, i t usudly is titrnted with a strong ncid, IICI, to determine excess base. The various pnrnmetcrs measured nre :

1. Titration nlknlinity E [IICOs-] + 2[CO,-] + [HrBOl-] + [OH-] - [IT'] 2. Carbonate nlkalinity = [I1CO:-l + ~[COI-]

titrntion nlknlinity 3. Specific alkalinity - chlorinity

Diesotved Qase-Tablo 20-6 gives tho saturation valucs of the major dissolvcd 1 giwcs in acbwatar with varying tcmpcrnturc nnd anlinity. Oxygen-Oxygen is introduced into senwntcr by surlncc mixing with the nt- '

I mosphere and by photosynthetic plants. Oxygcn distribution in the oceans (Fig. I

20-9) is monitored by biological nctivity nncl the presence of oxidizable organic

I matter. Thus, the oxygen content is not completely a function of solubility. The I

I TABLE 205-Concentration of Traco Metals In Seawater

1 Concen- Concen- tration in tration in Senwater, Seawater,

Ppb* Ppb*

................ Chromium.. 0.13-0.25 Molybdenum.. ................ 4-12 ................... Cobnlt.. 0.1-0.04 Nickel.. ...................... 0.75-2 ........................ Copper ..................... 0.7-27 Silver 0.145

..................... Gold.. 0.016-0.4 Tungsten.. ................... 0.12 ....,........... ........................ Manganese. 1.7-114 Zinc.. 1-20

Mercury.. .................. 0.16-0.27

* Ppb = parts per billion. . . - -

Flg. 20-0-Distribution of pH with depth a t 10°12'N, 26'36'W (data from Meteor Etpe- ditwn, 1026-97) (Pickardb),

fell-defined '--- -..- c..

oxygen profile usunlly shows n I\ rn a t nbout 1,w m where dead orgnnic matter raining down ~IUIIL N I J U G ~ : l r g r o m of high productivity reduces the oxygen content to below thnt supplied from the surfnce or from oxygen-rich deep wnters. Such an oxygen reduction can occur near shore in barred deep fjords and other nreas of poor circulation wit11 high organic debris.

Nitrogen-Apparently, nitrogen is affected little by biologicnl activity. Therefore, its concentrntion in senwnter is n direct function of solubility (Table 206).

Carbon Dioaride-Cnrbon dioxide is supplied to senwnter by plnnts plus respiring snirnnb, in nddition to the ntmosphere. The solubility of C02 varies grently, pnr-

TABLE 2

0-6

-Co

eff

icie

nts

o

f S

atu

rati

on

of

Atm

os

ph

eri

c G

as

es

(C.)

in W

ate

r (C

on

ce

ntr

ati

on

s o

f O

xyg

en.*

N

itro

ge

nb

an

d C

arb

on

Dio

xid

ee

as M

I p

er

La

nd

Mg-A

tom

s p

er

L in

Eq

uil

ibri

um

Wit

h 7

60 T

orr

=1 A

tmo

sp

he

re o

f D

es

ign

ate

d G

as

) (S

ve

rdru

p a

nd

oth

ers

13

' Fo

x (1909).

Dis

till

ed w

ater

, F

ox (1909);

seaw

ater

, Rak

estr

aw a

nd E

mm

el (1938b).

Bu

ch e

l a1 (1932).

afte

r B

ohr.

Con

cent

rati

ons

repr

esen

t am

ount

s of

fre

e C

O1

and

H~C

OI.

my

'

. *;I

DE

PT

H I

N K

ILO

ME

TE

RS

3."

-

2z 1

*

0

m

P

N

F:

0,

%2

I I

I I

I 0

.sL

' f x

z Y

t-0

. ..

. .

, .

N

# 2)

- 0-

Z

P

-I

E. -

D

" ;:-

0, p.

. .

IR

8-

.. C

C

. <

z,

s g

0,

$5

;

. .

gz-

3

'5 G

Es

A

rcti

c (S

outh

of

Gre

ento

ndl

m

CI

-aa

4-

C

. .

g w

1

::u ::

z.2

g 2.

5

52

-

- a L

-

0-

-2 0.

Tem

pera

ture

coz

. cO

ig- b-

kfg-

24'

M g-

Ato

ms

Chl

orin

ity,

o/,

?rll

/L O/L

O.............

49.24

4.40

16.......

....

. 40.1

3.GO

20 ............ 38.0

3.40

Ato

ms

N/L

1.59

1.33

1.26

02

Nl

Ato

ms

Ml/

L

N/L

14.63

1.31

9.36 1.08

8.96 1.03

MI/

L

29.38

24.8

23.6

MI/

L -

1118

980

947

MI&

23.00

15.02

14.21

Mg-

Ato

ms

O/L

2.62

2.22.

2.12

Ato

ms

C/L

50.2

44.0

42.5

M g

- A

tom

s N

/L

2 06

1.73

1.64

cot

MI/

L

17.80

11.56

10.99

MI/

L -

782

695

677

XlI

/L

1715

1489

1438

rag-

Ato

ms

C/L

35.1

31.2

30.4

Ato

ms

Ato

ms

C/L

M

I/L

O

/L

77.0 36.75 3.28

66.8 30.6 2.75

64.5 29.1

2.61

titularly invenoly with tempemture (Table 20-6). CO, dissociates rendily by tho following rcnctions :

I120 + COz 9 R~COI IX&Os 9 H+ f IICOs- t

HCOs- @ H+ + C0s- A t the p H of seawater-about &the bicarbonate ion, HC0,-, is the dominnte

dissolved specie.

26.1.3-MARINE GEOLOGY

Physiography of the Sea Floor-Fig. 20-10 shows the frequency distribution of oceanic depth with respect to area. Thd sliape of the curve outlines the gross physiographic provinces: (1) the continentnl shelf, from 0 to 200 m ; (2) the continental slope, from 200 to 3,500 rn; (3) the deep sen, from 3,500 to 6,000 m (mcnn depth of the occnn, nbout 4,000 m) ; (4) trenches, from 6,000 to about 10,000 m. A more complete description of the physiographic provinces is given in Table 20-7.

. ' TABLE 20-841assification of Deep-Sea Sediments (Classification Modified From Reveilel9) (Submarine Deposits by Wilde)

f

P e l a ~ i c Depoaita: Sediments that were a t one t ime within 200 m of the ocean surface and arrived a t the bottom by settling through the ocenn . A. Oozcs-skeletal remains of organisms greater than 30 %:

1. Calcium-carbonate ooze: a. Globigerina b.' Ptcropod c. Coccolith remains d. Mixed with clay, hydroxides, volcanic glass, detrital quartz and feldspar

2. Siliceous ooze: a. Rndiolarian b. Diatom remains c. Mixed with clny, hydroxides, volcanic glass, detrital quartz and feldspar

B. Red clay-skeletnl remnins less than 30% quartz, feldspar, mica, clny n~inerals ! mixed with meteoritic spherules, manganese nodules, shark's teeth and vertebrate hard

parts 1

Tekoemus Depoaita: Sediments derived from the lnnd and aarried to the site of deposi- tion by bottom currents

A. Organic muds-skeletal remains greater tlinn 30 %, clay in apprecinble amounts 1. Cnlcium carbonate, mud and sand:

a. Carbonate shells and clay b. Mixed with volcanic nnd detrital particles

2. Siliceous mud and sand: a. Siliceous shells and clny b. 'Mixed with glauconite, detritnl and volcnnic particles.

B. Inorgnnic muds-skelctnl remains less than 30% 1. Clay muds: detritnl pnrticles 2. Silty or sandy muds: detritnl pnrticles

'

3. Volcanic muds and sunds: volcnnic particles

Submarine deposits: Sediments that never were exposed to the atmosphere A. Dctritul-erosion products from submarine erosion or from submarine volcnnic

, ' eruptions mixed with pelngic deposits B. Chemical-authigenic formation on the sen floor:

1. Authigenic clays 2. Mangnnese nodules 3. Phosphate nodules, mixed with pelngic and terrigenous deposits

. : . . . . . . . . . . . . . . . . . 9 . ' .

' Marlne Rock type^ . . Sediments

Classificalwn-A clnssificntion of -deep-scn sediments is given in Table 20-5. Shelf dcposits, because of their obvious aflinities with the continents, usunlly

nre not givcn a unique mnrine clssification. Table 20-9 gives the areal c x k ~ l t of the cornmoncst marine sediments.

dlincmlogy-The minernls in encl~ sediment clnss nrc further identified by .their origin (Tnblc 20-10).

Sediment Distribution-Fig. 20-11 shows the major environmental factors of the oceans.

Terrigenous Deposits-Terrigenous deposits are found adjacent to land areas, pnrticularly where there are high volumes of sediments carried t o the sea. Most t>errigenous materid is deposited on the sh~llom shclf. I n many nreas, such as off central Cnlifornia, the Eastern Senboard of the United States and in the Bay

TABLE 20-%Area Covered by Marine Sedlments (Kucnento) ' . . . . . .

1 enhnnced by localized supersaturntion or changes in the oxidntion-reduction potcntinl 2 new the scdimentacnivnter intcrfoce.

f Ferromanganese Ozide Deposits-Fcrromangnncsc oxides are found i n two distinct forms: (1) nodulcs and (2) crusts. Nodules occur rts bottom surfncc features in

!

Aren. Millions % of Type of Deposits Sq Km Sea Floor 5

I

. . . . . .................... . Shelf.. , 3 0 ' 8 . .............. I . . - . , . . Terrigenous.. ;. 63 18 Pelagic.:. .......:.. ; ........ 268 74 "

I .......... . Globigerina ooze.. 126 35 . : 1 Pteropod ooze.. 2 1 .............

\ .............. Diatom o o z ~ . 3 1 9 ........... i Radiolnrian ooze. 7 2 ................ Red clay.. 102 28

TABLE 20-1O-Genetic Classlflcation of Marlne Mlnerals . ,

1. Authigenic: minerals formed directly in the seawater ' ' . 3

2. Pyroclastic: detritus from volcanic eruptions 3. Biotic: hnrd pnrts formed by an organism in its life procese 4. Terrigenous: erosion products from the continents . , (. . . . 5. Dingenetic: minerals altered from their state ns a response to

mnrine environment 6. Extrsterrestrinl: material from outer space

' of Bengnl, large volumes of sediments nre cnrricd to the deep sea via submarine cnnvons nnd deposited in large submnrine fnns nnd nprons.

Pelagic Deposits-Pclagic dcposits arc almost exclusively dcep-sea in arens of little terrigenous contribution. Organic deposits or oozes are found ns n function

o f organic productivity in the surface water, t.he rate of solution of the orgnnic hard part, nnd the depth of wntcr. Oozes mill form in regions where the rate of production exceeds the rate of solution in the wntcr column. Carbonate oozes,

' which nre relatively solublc, are found in shallow to intcrmediaie depths.

Siliceous OoeesSiliccous oozes, ~l1ic11 nre relatively insoluble, occur where cithcr (1) siliceous organisms IIRVC a highcr productivity tllnn c~rbonnte organisms, or. (2) silica hnrd pnrts are prescrvcd at the expense, of carbonate hard parts due to diffcrentinl solutions in the wnkr column.

Inorgatlic Clnys-Inorgnnic pelngic dcposits, such ns rcd clays, are found in rcgions of (1) low orgnnic produclivity or (2) deep mntcr where surfnce-produced orgnnic mattcr hns dissolved before sinking to t.lie bottom.

Chemical Deposils-Chclnicnl dcposits are limited to arens (1) of vcry low rates of pel~gic or terrigcnous deposition or (2) where cl~emical precipitation is

Fig. 20-11-The marine environment (ICuenen~O).

deep water often associnted with red clay. One mcnns f o ~ rrnation and growth may be the migration of iron and mangnncsc ions in solut~on from the reducing layer within thc sediments to the surface oxidizcd lnyer where the metnllic

, ions precipitate much like desert vnrnish. Crusts u p to sever$ centimeters thick

- ..#

I.. +=

E

G d 0

4

0 .- a

s M

i 5

U )

t4 ." I..

K

* 0 .- C 0

6i

0 .- + ul oi w 0

2 !$

0 .- 9 M

1 -c

. . . . ?.'i..,- ".., - . ,. . . T: , . .!J E ~ v ~ n o i u ~ s k l b 20-21 ." . :. ,;. ,

. ,.I ; , . ., n . . -. f ~ m i -. outcrops on the tops and flnnkv of sen mounts where iron and mnnganese I . A . , , 11ns nppurcntly been rolenscd by undcrwetcr wontl~ering of iron- nnd mnnganeuc-rich

bnsnlts. ...

Phosphorile Dcposils-Phosphorite deposits occur as (1) nodules nnd crust by replncement of calcite by npntite in offshore carbonate bnnks in the presence of phospl~orous-rich upwelling water or (2) phosphatic muds-again in regions of upnrelling of deep phosphorous rich water.

~\felalliferous ~lrilids-Iron oxide, Fe20.1, geothite with sphnlerite, ZnS with other trnce metals nssocinted wit.h the hot saltv brines occur in certain closed basins in the Red Sea. The origin of suth deposits still is uncertain. The high metallic content suggests these deposits are a result of interaction of percolating sen-water with continental rocks in regions where the oceanic ridge-rise system intersects continental crust.

Igneous Rocks Bnsalts are the most common igneous rocks encountered o n the sen floor.

Tholeiitic basnlts are found in deep-sen nreas, whereas nlknli bnsalts are found nssociated with islands. Mnfic rocks, such ns scrpcntines and peridotites, have been dredged from some trenches and from oceanic ridges.

! . . . . . : , TABLE 20-12-Blotlc Minerals

' . I . . , . i Organism Preserved Part Mineral . .

' : r - L , - . , ; , t Foraminifera Test Calcite '

i Coccolithophorids Platelet Calcite I Pteropods Shell Aragonite ........ Dintoms Skeleton Opaline silica

i Rndiolnria Skeleton Opnline silicn Silicoflngellates Skeleton Opaline silica Sponges Spicules Opaline silica

1 . - ... .-..*! Acntharid radiolaria Skeleton Celectite Fish Skeleton and scales Apatite Mammals Skeleton Apatite

. . . Bncteria - Mn oxides, sulfates

... .__. -. ._-

. . ; .. . ,. Table 20-13 lists the chemical composition of typical marine sediment and I rock types and comparison values for average continentnl sediments, granites and

. . - . , . *. basalts. . ., . . St~cture--The thickness of the crustal rocks underlying the ocean basins is . . .

much thinner than for the continents. The distance to the Mohorovicic discontinuitv. the boundnry between the crust and the mantle, is only about 10 km (including 5 km of wnter in the ocean bnsin) ns opposed to 35 krn for the continentnl areas).

The layering of material in the ocean bnsins is given in Table 20-14' bnsed on explosion seismic work. Acoustic profiling methods using electric nrcs, exploding wires or nir bubble collapse can see only through seawnter nnd the first sediment layer. Thus, in ncoustic profiling the top of the second layer is the neoustic basement. Reflectors in the first layer cnn be volcanic nsll layers or turbidite terrigenous sandy lnyers. I n shnllow water on continentnl shelves nnd slopes, deeper penetrntion than 0.5 krn cnn be obtnined. As oceanic sediments hnve acoustic velocities on the order of that of senwnter (Table 20-141, penetrntion often is given in seconds a-9 shown on the recorder. Thus, 1 sec of pcnctration equnls npproximntely 400 fathoms = 2,400 f t for a recorder with a fixed speed of sound = SO0 fathoms per sec.

T o generalize, the shelf nrens of the oceans nre underlain by continental granitic basement rocks while the deep ocean is underlnin by true oceanic bnsnltic rocks.

TABLE 2

0-13-

Ch

emic

al C

om

po

siti

on

of

Typ

ical

Ma

rin

e S

edim

ent

and

Ro

ck T

ypes

I.

'-

I1

111

, .

V

. VI

VIE

- VIII

IX

:

X

XI

=v

,.

Avg

. XI1

.' O

cean

ic

Oce

anic

O

cean

ic

Red

Sea

A

vg.

Red

C

alc.

:

Sii

c.

hln

A

vg:

Avg.

Tho

lei-

A

lkal

i P

eri-

G

eo-

Red

Sea

S

ed.

Cla

y O

oze

Ooz

e N

odul

e G

ral1

1t.e

B

asal

t it

ies

Bas

alt

doti

tes

thit

e S

ulfi

de

......

......

. S

lot

57.95

A11

0a. ..

......

.'.. 13.39

Fer

Oz.

. ............

3.4

7

FeO

. .....

......

.. 2.08

AIg

O..

...........

2.65

. CaO.. ..

.........

5.89

....

....

...

Na

rO..

1.1

3

. K

zO..

...........

2.6

6

.............

Hz

0

3.23

CO

1 .....

......

...

5.3

8

......

....

CaC

Oa.

. ...

......

A

IgC

01..

1.6

1

2.91

' 0

.01

Z

nO

0.7

12.2

0.17

0.1

6

0.0

7

11 Afn

.04

1.1

-

1.1

0.1

6

0.93

CuO

0.3

4.5

..

.. ~

~ -

-. -

I. P

etti

john

.tl

p.

106.

VII. P

irss

on a

nd K

nopf

.2'

p. 209.

:: :..

...

. ,

.- .

. . -

.

.-

.

. .

11.

El

1lra

keel

and

Rile

y.2'

V

III.

E

ngle

and

oth

ers,

16 p

. 723.

. .

.-.

. -

: /

-.

.

..

.

..

-

..

..

.

..

..

..

..

111. El

Wak

eel

and

Rile

y.':

IX.

En

gle

and

oth

ers,

l6 p

. 723.

- .

I ,:

,.

- .

. .

i i' -.

.

..

.

. .

5,

.:

;

IV. El

Nak

eel

and

Rile

y.',

; '

- X

. E

ngle

an

d F

ishe

r." p

. 11

38.

: -

. -.

I-

,

. . .

..

.

-.

- .

..

..

.

..

.

. .

., .

. L'

. V

. hl

ero,

fJ p

. 179.

XI.

Bis

hoff

,t' p. 384.

. i

3!

: -,

.. .-

. . .:

. .

. .

- ..

;

i .

..

-

..

..

>.

-.

- VI.

Pim

son

and

Kno

pf,'*

p.

169.

-

. XII. B

isho

ff,*

' p. 384.

- ,i .

, ..,

. .

..

.

.. ,

. .

i-

-.

ar

rr

L

Hb

b

OW

NN

0-3

,a z 5.

1

2 2 1.

-. 3

u"S

a

%-

a;:

g3

" Y

B I

tonturcs of tho scs floor. The gcologicnlly nctive acannio ridged and plnte botindnries .nppcnr to play IL significant pnrt it1 tho formation of some potcntinlly ccollomic mnrinc mineral deposits. .-

REFERENCES:

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2. Menard, H. W., and Smith, S. M., "Hypsometry of Ocean Basin Provinces," Journal o/ Geophysical Research, Vol. 71, 1966, pp. 4305-4325.

3. Harvey, H. W., The Chemi~lry and Fertility of Sea Waters, Cnmbridge University Press, 1966.

4. Cox, R. A., International Oceanographic Tables, Unesco, New York, 1966. 5. Pickard, G. L., Descriptive Physical Oceanography, l'crgamon I'rcss, New York. 1963. 6. Knudsen, M., IIydrographic Tables, G. E. C. Gad, Copenhagen, Denmark, 1901. 7. Dietrich. G., General Oceanography, John IViley, Ncw York, 1963. 8. I'vlunk, W., "A Critical Wind Speed for Air-Sea Boundary Processes," Journal of

Marine Research, Vol. 6, 1947, pp. 203-218. 9. Defant, A., Physical Oceanooraphy, Pergamon Press, New York. 1961. 10. Ekmnn, V. W., "On the Influence of the Earth's Rotation on Ocean Currents,"

K. Svenaka Vetenskapad, Vol. 2 , No. 11, 1905. 11. Formin, L. M., The Dynamic Method in Oceanography, Elsevier, Amsterdam, 1964. 12. Munk, TV., "The Circulation of the Oceans," Scientific American, Vol. 193, No. 3,

1955, pp. 96-104. 13. Weigel, R. L., Oteanographical Engineen'no. Prentiee-IInll, Englewood Cliffa, N.J.,

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by N.M.S. Challenger During the Years 1873-1876," Phgsics a d Chemislry, 1884, pp. 1-251.

16. Lyman, J., and Fleming, R. R., "Composition of Sea Water," Journal of Marine 12esearch, Vol. 3, 1040, pp. 134-146.

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17. Culkin, F. C., nnd Cox, R. A., "Sodium, Potassium, Magnesium, Calcium and Strontium in Sen Water," Deep-Sea Research, Vol. 13, 1966, pp. 789-804.

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10. Revella, R., "Marine Bottom Snmplcn Collected in tile I'ncific Ocean by the Carneoic on I ts Seventh Cruise," Pub. 556, 1944, Cnrnegie Institute, Washington, D.C.

20. Kuenen, H., Man'ne Geology, John Wiley, New York. Cl~aprnarl& Hall, London, 1950. 21. Pettijohn, F. J., Sedimentary Rocks, Harpers, New York, 1957. 22. El Wnkeel, S. X., and Riley. J. P.. "Chemical and hlineralo~ical Studies of Deep-

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BasnlGs and the Uppcr hlantlo," Bulletin Geologicnl Society of America, Vol. 76, 1965. pp. 719-734.

26. Engle, C. G. nnd Fisher, R. L., "Lherzolite, Anorthosite, Gabbro and Basnlt Dredged .

From tho Mid-Indian Ocean Ridge," Science, Vol. 160. 1969, pp. 1136-1141. 27. Dishoff, J. L., "Red Sea Geothermal Brine Deposits: Their hlineralogy, Chemis-

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28. Rnitt, R. W., "Tho Crustal Rocks," Chap. 6. The Seas. Vol. 3 of The Earth Beneath the Sea-History, Hill, M . N . , ed., John Wiley, New York, 1963, pp. 85-102.

29. Nafe, J. E., and Drake, J. L., "Physical Properties of Marine Sediments," Chnp. 29. Ref. 28, pp. 794-815.

30. Horn, D. R., IIorn, B. hf., and Delnch, M. N., "Sonic Properties of Deep-Sea Cores From the North Pncific Basin nnd Their Bearing on the Acoustic Provinces of the North Pacific," Tech. Rpt. 10, 1968, Lamont Geological Observatory.

31. mTilson, J. T., "The Development and Structure of t he Crust," Chnp. 4, The Earth . as a Planet, Kuiper, G., ed.,University of Chicago Press. Chicago, 1954, pp. 138-214.

. , ' ,,,' .

BIBLIOGRAPHY:

"Oceanography Information Sources," Committee on Oceanography, Div. of Earth sci; ences, National Academy of Sciences, National Research Council, Washington, D.C. 1966.

Fairbridge, R. W., The Encyclopedia of Oceanography. Reinhold, New York, 1966. I-Iedgpeth, J. W., ed., "Trentise on hlnrine Ecology and Paleontology," Memoir 67, Vol. 1,

1957, The Geologicnl Society of America, p. 1290. Ilill, &I. N., ed., The Sea, John Wiley, New York, 1963. "Guide to Submission of Data," Tech. Bull. No. 1, 1st ed., July, 1969, National Ocean-

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i s t ~ and General Biology, Prentice-Hall, Englewood Cliffs, N.J.. 1942. "Catalogue of Accessioned Publications," Sup. No. 2, 1970, World Da ta Center--A,

Oceanography, Washington, D.C. . .

. .. .,. 20.1.2-Marine Chemistry-see also Refs. 3, 7, 14-18 . . . , . . ,. . .

XlncKenzie, F. T., and Garrels, R. M., "Chemical Mass Balance Between Rivers and Oceans, American Journal of Science, Vol. 264, 1966, pp. 507-525.

XfcIlhenney, W. F.. and Zeitoun, M. A.. "A Chemical Engineer's Guide t o Sea Water," Chemicd Engineering, Nov. 1909, p. 81. . ..

Stewart. F. H., "hlarine Evaporites," Data of Geodemislry, Fleischer, M., ed., Chap..Y. Prof. Paper 440-Y, 1963, U.S. Geological Suivey. . . . . . . . .

. , . . . I ,*. . , '. , . . , . . . . . . ., . 20.1.3-Marine Geology-see also Refs. 19-32

. . . Alexander. T., "The Secret of Sprending Ocean Floors." Fortune, 1969, pp. 112-150. Benll, A. O., Jr., "Deep-sea Drilling Project Throws New Light on Gulf Sedimentation,"

Offshore Explor~tion, The Oil and Gas Jourtml, pp. 94-108. Cotter. C. H., The Physical Geograph~ of the Oceans, 1965. Emery, K . O., "Atlantic Continentnl Shelf Slope of the United States-Geological Back-'

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Symp. on Economic Importance of Chemicals From the Sea, American Chemical ! Society, 19G3. !

hfennrd, H. W., Man'ne Geology of the Pacific, McGraw-Hill, New York, 1064. 1 Orownn, E., "The Origin of Ocenn Ridges," Scientific American, Oct. 1969, pp. 103-119. j Pratt , R. M., "Atlantic and Contincntnl ahelf nnd Slopo of the U.S.-Physiography and

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Spec. Rpt. 44, 1955. Californin Dept. of Natural Resources, Div. of Mines. i :

Uchupi, E., "Atlnntic Continental Shelf and Slope of the US.-Physiography," Prof. Paper 5 2 9 4 , 19G8, U.S. Geologicnl Survey.

Wilde, P., "Minernl Resourccs," Chap. 13, California and Uae ofthe Ocean, Xeim, R., ed., i I Institute of hlarine Resources. 1965. Ref. 65-21. PP. 13-0-13-27.