SEDIMENTARY ENVIRONMENT

Question 1

SITES WHERE SEDIMENTS CAN ACCUMULATE AND BE SEDIMENTARY ROCKS

Answer 1

SEDIMENTARY ENVIRONMENT

Question 2

3
CRITERIAS IN RECOGNIZING SEDIMENTARY ENVIRONMENTS

Answer 2

1. PHYSICAL
2. CHEMICAL
3. BIOLOGICAL

Question 3

BEDDING CHARACTERISTICS, NATURE OF FORMATION CONTACTS, SEDIMENTARY
STRUCTURES, DIRECTIONAL PROPERTIES (I.E. RIPPLE MARKS, FLUTE MARKS, GRAIN
ORIENTATION

Answer 3

PHYSICAL-

Question 4

MINERAL COMPOSITION, AUTHIGENIC MINERALS

Answer 4

CHEMICAL

Question 5

BIOLOGICAL

Answer 5

FLORA AND FAUNA ASSEMBLAGES (FOSSILS)

Question 6

A BODY OF ROCK WITH SPECIFIC CHARACTERISTICS IT IS USED AS A STRICT
SENSE OF A ROCK PRODUCT
(SANDSTONE FACIES), IN A
GENETIC SENSE FOR THE PRODUCTS OF A
PROCESS BY WHICH A ROCK IS THOUGHT TO HAVE FORMED
(TURBIDITE FACIES), IN AN
SENSE FOR THE ENVIRONMENT IN WHICH A ROCK IS THOUGHT TO HAVE FOR
AS A TECTO-FACIES (POST-OROGENIC FACIES)

Answer 6

FACIES

Question 7

DEPENDENT ON THE FOLLOWING FACTORS:

Answer 7

• SEDIMENTARY PROCESSES
• SEDIMENT SUPPLY
• CLIMATE
• TECTONICS
• SEA LEVEL CHANGES
• BIOLOGICAL ACTIVITY
• WATER CHEMISTRY
• VOLCANISM

Question 8

ALLUVIAL FANS (FIGURE 1) ARE LOCALIZED AND THEIR SHAPE APPROXIMATES
A SEGMENT OF A CONE. THEY DEVELOP IN AREAS OF HIGH RELIEF, WHERE THERE IS A ABUNDANT SUPPLY
OF SEDIMENT. THESE FANS MAY DEVELOP IN HUMID ENVIRONMENTS, BUT ARE BEST KNOWN IN ARID
REGIONS WHERE EROSIONAL PROCESSES ARE NOT AS ACTIVE. THEY CAN PASS DOWNWARD THROUGH
A VARIETY OF SEDIMENTARY ENVIRONMENTS, OR BUILD INTO LAKES, ALLUVIAL OR DELTAIC PLAINS, TIDAL
FLATS, AND DEEP WATER BASINS

Answer 8

ALLUVIAL ENVIRONMENTS

Question 9

ARE THOSE AREAS IN WHICH RIVER FLOW DIVERGES AND REJOINS AROUND
BARS WITHIN A MORE OR LESS DEFINED CHANNEL. SETTINGS WHICH
COMMONLY PRODUCE PEBBLY BRAIDED CHANNELS ARE GLACIAL OUTWASH
AREAS, HUMID FANS, AND WADIS OF SEMIARID REGIONS. THE SEASONAL
FLUCTUATIONS OF STREAM WATER FLOWS DETERMINE THE TYPE OF MEDIUM
FEATURES THAT ARE FOUND IN PROGLACIAL SEDIMENTS. OUTWASH FANS AND
PLAINS HAVE COMPLEX CHANNEL PATTERNS, WITH THE MAIN FLOW USUALLY
RESTRICTED TO A WELL DEFINED ZONE

Answer 9

BRAIDED STREAM ENVIRONMENTS

Question 10

3 VARIATIONS OF BARS FORMED
_______________ARE DIAMOND OR LOZENGE SHAPED, AND ARE THE MOST OBVIOUS
FORM IN PEBBLY BRAIDED STREAMS.
________________CAN BE ATTACHED TO EITHER BANK AND ARE
COMMONLY EXTENSIONS AND MODIFICATIONS TO THE FLANKS OF LARGER LONGITUDINAL
BARS.
________________MOST COMMON IN SANDY, LOW SINUOSITY STREAMS, BUT ALSO OCCUR
IN PEBBLY ONES.

Answer 10

LONGITUDINAL BARS

BARS IN CURVED CHANNEL REACHES

TRANSVERSE BARS

Question 11

BRAIDED STREAM ENVIRONMENTS
________________ - PREDOMINANTLY COARSE SANDS AND CONGLOMERATES, OFTEN RED
COLORED WITH _______________

Answer 11

COMMON LITHOLOGIES-
NO ORGANIC MATERIAL -

Question 12

TABULAR AND TROUGH CROSS-STRATIFICATION CAUSED BY MIGRATION OF
BARS, SAND WAVES AND DUNES. IMBRICATION IS COMMON IN CONGLOMERATES. MINOR
CROSS-LAMINATION IS CAUSED BY RIPPLE MIGRATION IN ABANDONED CHANNELS OR IN
NEAR-FULL CHANNELS. THERE IS AN OCCASIONAL FINNING UPWARDS SEQUENCE
REPRESENTING FILLING OF CHANNELS.

Answer 12

STRUCTURES

Question 13

MEANDERING CHANNELS, UNLIKE BRAIDED CHANNELS,
OCCUPY ONLY A SMALL PART OF THEIR FLOODPLAIN AT A
GIVEN TIME. THE SHIFTING OF THE CHANNEL IS A
FUNCTION OF CHANNEL SINUOSITY.

Answer 13

MEANDERING RIVER DEPOSITS

Question 14

MEANDERING RIVER DEPOSITS
- MEDIUM TO FINE SANDSTONES, CLAYSTONES AND SILTSTONES, WITH
A ROUGHLY 50/50 RATIO OF SANDSTONES TO MUDROCKS. IT MAY ALSO CONTAIN MINOR
CONGLOMERATES AND COALS. SANDSTONES ARE GENERALLY ARKOSIC. POSSIBLE CALICHE IS
PRESENT IN MUDROCKS OR SIDERITE NODULES.

Answer 14

COMMON LITHOLOGIES

Question 15

CHANNEL SCOUR SURFACES, WITH COARSE LAG DEPOSITS FOLLOWED BY
TROUGH CROSS BEDDING, FLAT BEDDING AND THEN RIPPLE CROSS-LAMINATION. FLOOD
PLAIN DEPOSITS MAY HAVE THIN CREVASSE SPLAY SANDSTONES WITH SOLE MARKS AND
CLIMBING RIPPLE LAMINATION.

Answer 15

STRUCTURES

Question 16

-ARE THOSE SEDIMENTS THAT ARE REWORKED AND LAID DOWN THROUGH THE ACTION OF
WIND CURRENTS. SINCE DESERTS ARE AT A DEPOSITIONAL EQUILIBRIUM, THAT IS THEY ARE AREAS
OF NEITHER NET EROSION OR DEPOSITION, ANCIENT EOLIAN SEDIMENTS WILL PRIMARILY BE
COMPOSED OF SANDS. THIS IS BECAUSE LARGER GRAINS WILL NOT BE TRANSPORTED BY THE
WIND AND FINE GRAINS WILL BE BLOWN OR WASHED AWAY. THIS RESULTS IN MAJOR
DEPOSITS OF SAND GRAINS THAT ARE VERY CLEAN AND RELATIVELY HOMOGENOUS IN SIZE.

Answer 16

EOLIAN ENVIRONMENT

Question 17

FINE TO COARSE SANDSTONES WELL SORTED, WELL ROUNDED, POSSIBLY
FROSTED, GENERALLY QUARTZ ARENITES, NO MICA, NO GLAUCONITE, NO CARBONACEOUS
MATERIAL, POSSIBLE PRESENCE OF DREIKANTERS, RED COLORATION. THERE ARE OFTEN SHARP
DIFFERENCES IN GRAIN SIZE BETWEEN LAMINAE. IT MAY CONTAIN MINOR CLAYSTONE DEPOSITS
WITH MICA FROM INTERDUNE AREAS.

Answer 17

LITHOLOGY

Question 18

• DOMINATED BY LARGE SCALE CROSS-BEDDING. INTER DUNE DEPOSITS MAY
  SHOW MUD FLAKES AND ADHESION RIPPLES. THERE MAY OFTEN BE MANY INTRAFORMATIONAL
  UNCONFORMITIES (REACTIVATION SURFACES). IN CORES, A GRADUAL INCREASE IN ANGLE OF
  DIP OF LAMINATION FROM SUB-HORIZONTAL TO STEEP CAN OFTEN BE SEEN REPRESENTING THE
  TOESET (BASE) OF DUNE TO THE FORESET

Answer 18

STRUCTURES