W7 classification of carbonates handout

Question 1

when classifying carbonate rocks

Answer 1

most significanr partilcle in rock is described

Question 2

oolitic limestone or oolitic

Answer 2

if a rock is composed of . ooids

Question 3

ooids

Answer 3

Ooids are small (commonly ≤2 mm in diameter), spheroidal, “coated” (layered) sedimentary grains, usually composed of calcium carbonate, but sometimes made up of iron- or phosphate-based minerals.

Question 4

skeletalootic

Answer 4

if limestone contains skeletal fragments

Question 5

allochemical rocks

Answer 5

contain more than 10% allochems ( transported carbon grains)

Question 6

sparry allochemical limestones

Answer 6

contains sparry calcite cement of clear coarsely crystalline mosaic calcite crystals

Question 7

microcrystalline allochemical limestone

Answer 7

contains microcrystalline calcite mud, micrite, which is subtransluscent greyish or brownish particles less than . 5 microns in size

Question 8

micrites

Answer 8

rocks with appreciable matrix

Question 9

Sparites

Answer 9

matrix free rocks, contain sparry calcite cement

Question 10

grainstones

Answer 10

grains of a limestonee are touching each other and sediment contains no mud

Question 11

packstone

Answer 11

carbonite is grain supported, contains a small percentage of mud –> packstone

Question 12

wackestone

Answer 12

mud supported but contains more than 10% grains

Question 13

mudstone

Answer 13

less than 10% grains and is mud supported

Question 14

floatstone

Answer 14

wackestone in which grains are greater than 2mm in size

Question 15

rudstone

Answer 15

coarser grainstone