Page 111 - Petrology of Sedimentary Rocks

ENVIRONMENTS

DUNES LOESS
- - .._
BAR or BEACH LAGOON
ABYSSAL NERITIC

Gvl
Sand

Silt
Clay

_-e-w- r
&dhinq --- -- -- -a--- ---- - -. .’ ,
a-9
-w-e-
C(&dhe ,_--_- ----- ------- -____- - _--__ _---a
hcid
NOTE : All above factors affected by geologic history. For example the sediments we
find now in the neritic zone may have actually formed when sea level was much lower--
anciecbeaches are often buried under several hundred feet of water and their
characters wiil be those of beach sands although they are now deep in the neritic
zone. Beaches contain gravel if (1) gravel is the result of past geologic history
(e.g. glacial); (2) hard rocks outcrop at the coastline; (3) competent rivers carry
gravel to the sea.

MANTLE
FLOOD- RIVER ALLUVIAL
DELTA

Fldpl4m, swsnp and nedtie

Gvl
Sand
Silt
Clay

ouid+ng ,-, r---. . r----x ‘---. *, n ,------------------ ----e a
R&m9 A :e_ e-J-\ _ _ .; 2 l ..2 ..* \ -*-.*
\ i
pHAlkaliwAcid --------. -------- _/ ----*-
- -___^____d ---me----., c
\ a ---w- /*
‘s ----- /MC
NOTE : Proportion of gravel in the various loci depends on (1) nearness to hard rock
outcrops or older reworkable gravel deposits, (2) competency of currents.
105