Page 26 - Maldonado_Stanley_1976

22 SMITHSONIAN CONTRIBUTIONS TO THE. EARTH SCIENCES

///////
'//////// ///// ////////
/ / / ./ / / / / / / / / / / / / / / / / / / / / / ! :::· :0/1
/////////////////////////
,',',",' ","9",",'/"/"/",.',",",","/","/"/"/",",",' l:* . .'~:! * Rock and Grave!
/ / / /6/ / / / / / / ,. / / / / / ,. / / / / / / / ~------- .........
/ ," // ," // ..," ," ," ,.,. // ," //// ," ..," ," //..,"?-~-·----..t -L_!.__, STRAIT OF SICILY
D . Sand llnd Sllt
/////////////////
///////////////~------- SURFACE SEDIIEIT DISTIIIUTIOI
/ / / / / / / / / / / / / /~ / / / / / / / / / -' ___ o.___ _______ _
~--! • Clay
',',',',',',',',' ~
, ,/~---------~--- 1--; VMud

l
l~~~li ----+--t-~~r ~!.Jr~------.,~~of-Aif-~~~---=-

l
~·
l~

i

///////////////////////
* //////////////////////
// /////// ///.1'///t.l'//
FIGURE 16.-Map showing surficial sediment distribution in the Strait of Sicily.
(From Akal, 1972.)

related to a volcanic source. A survey of the day is found in some basins; (3) moderate to well-
minerals in various Strait of Sicily environments stratified sand and mud units that include gravity
is detailed by Blanc-Vernet and others (1975). flow deposits (sand and mud turbidites, grain flow
units) andjor ash layers interbedded with hemi-
pelagic mud; this assemblage is typical of deep
DEFINITION oF MAJOR SEDIMENT TYPES IN CoREs
basins and the Strait Narrows. Graduai transition
Our study emphasizes the vertical and regional from one lithological assemblage to another is also
distribution of sediment types recovered in cm·es. recorded in the cores.
Three main assemblages are recognized in Strait of Cores containing assemblages 2 and 3 generally
Sicily cores: (l) coarse, calcareous sand layers in- display an upper 5- to 40-cm thick layer of oxidized
terbedded with mud and sandy lutite deposits; this light brown (5 YR 6/3) or yellowish brown (10
association prevails on shallow banks; (2) pre- YR 6 /4) mud; olive gray mud lies below this and
dominantly homogeneous (nonstratified, biotur- the vertical color change is usually transitional.
bated) light olive gray (5 Y 5 /2) to dusty yellow The five major sediment types distinguished in
(5 Y 6j4) mud in which the most important struc- Strait of Sicily cores include: (l) coarse calcareous
tures are biogenic ones; this type occurs most com- sand; (2) sand- to silt-size sediment; (3) ash; (4)
monly in the neritic-bathyal environments and also mud; and (5) sapropel and organic ooze.