Lecture 7 - Facies Models Part II

Question 1

What are aeolian desposits?

Answer 1

this is where incoming radiation heats the lower lats and takes mositire from here and moves it to the high lats, meaning a dry arid enviroment such as a desert

Question 2

what is sandblasting?

Answer 2

Grains move just above the sediment surface by saltation colliding with toher grains

Question 3

What is sandblasting effects on pebbles?

Answer 3

Sand blasting gives pebbles curbed or straight sides theses are called Ventifacts

Question 4

What is the most common desert mineral

Answer 4

Quatz

Question 5

What else occours here?

Answer 5

microscopic pitting and frosting

Question 6

What is the sorting and rounding of these sand grains

Answer 6

Well rounded and well sorted

Question 7

Wind transport properties

Answer 7

Wind is obvsiously much less dense than water so a really strong wind is needed to transport size grains.

Question 8

What does this wind form

Answer 8

Dunes, either around obstacles forming two dunes then the weak eddies allow the dunes to grown to form one large sand dune.

Question 9

explanation of sanddune migration

Answer 9

Sand dues are eroded or the windward side and deposited on the lee slope. Successive slip faces make for cross bedding.

Question 10

Techtonic setting for sand dunes

Answer 10

Inland basins, 10-30defrees or behind mountain rain shaddows

Question 11

Geometry of sand dunes

Answer 11

Thick tabular bodies can go for 100s of km

Question 12

Sedimentolofy

Answer 12

Enormous cross cut beds
some mud cracked shales
desert pavement gravles
well rounded
quatx rich
no fine matrix

Question 13

Fossils?

Answer 13

Rare footprints, insect burrows

Question 14

What do these cross cut beddings in the rock record indicate

Answer 14

Past wind directions

Question 15

Deltas explaination

Answer 15

Sedimenty desposits at river mouths, deltas prograde (build out)

Question 16

What are the three types of deltas

Answer 16

Small, Lobate, elongate

Question 17

One delta can contain three enviorments, what the they?

Answer 17

Delta plain, delta front, prodelta

Question 18

Techtonic setting of a delta

Answer 18

Passive margins and subsiding basins

Question 19

Geometry of a delta

Answer 19

Roughly tirangluar plans

Wednge shape in cross section

Question 20

Sedimentology

Answer 20

Coarse sand to fine mud, sometimes coal ripples and cross bedded sandstones

Question 21

Fossils

Answer 21

Organic matter common in interdistribuaty areas

Question 22

Preitidal envroiments explainations

Answer 22

found between high and low tide, found in costal regions where river sediments < marine eriosin, Unlike prograding deltas, sediment in peritidal environments is reworked by tides

Question 23

Peritidal tectonic settings

Answer 23

passive margin with shallow coastal regiions

Question 24

Geometry

Answer 24

Tabular, local sand bodies paralell to shorine

Question 25

Sedimentology

Answer 25

Sand and mud cracks, hering bone cross cutting bedding

Question 26

Fossils?

Answer 26

Oysters, plant remans and algea mats