6 - clastic rocks

what is the grain size classification system called

uden wentworth

large to small grains

gravel, sand, mud

silt vs clay

silt = gritty

clay = not gritty

gravel consists of what types of rocks

breccia (angular), conglomerate (round)

also boulders, cobbles, pebbles

mudrocks consist of what

silt and clay

example of highly mature vs not mature environment

high maturity = beach

low maturity = glacial till

poorly sorted rocks have ___ (high/low) porosity

low

if matrix is present the rock is a

wacke

if no matrix is present the rock is

arenite

3 end members of the triange

quartz

felspar

lithics

if more than 25% feldspar present what is it called

arkose

common minerals in sed rocks

quartz

fsp

lithics

micas and clays

heavy minerals

biogenic material

clay minerals that are deposited are called

detrital

clay minerals that grow in pores are

authigenic

3 types of matrix

protomatrix, pseudomatric, epimatric

protomatrix is also known as….

detrital

psedudomatric is what

mudclast compaction, from a shale, gets smushed

epimatrix is also known as

authigenic (not really a matrix tho)

most common cement

silica

other types of cement

silica

carbonate (poikilotopic, calcite spar)

what are poikilotopic cements

carbonate cements, envelops a number of grains, called syntaxial overgrowth if in optical continuity with grain

what are calcite spars

carbonate cements, fills pore space

calcite spars fill pore spaces in what way

1. drusy: crystals increase in size away from the grain

2. isopachus: thin fibres perpendicular to grain surface

major types of sandstone based on mineral/rock content

quartzite, arkose, lithic, greywacke

what is provenance

source of detritus

minerals: first to crystallize to last to crystallize

olivine, pyroxene, amphibole, biotite mica, kfsp, muscovite, qtz

fast weathering to slow weathering minerals

olivine, pyroxene, amphibole, biotite mica, kfsp, muscovite, qtz