Lithofacies

Lithologies

Sedimentary Structures

Depositional Environment

Expected Well Log Gamma Values

1

Moderately to well sorted sandstone, variably dolomitic

Trough and tabular, herringbone cross stratification, horizontal laminations

Subtidal sand bars

~100 - 200 (cps)

2

Sandstone, siltstone, dolostone

Ripples, mudcracks, bioturbation, flaser bedding

Intertidal sand flats

~150 - 250 (cps)

3

Dolostone, siltstone

Cryptalgalaminations, rip up clasts

Tidal ponds

~60 - 150 (cps)

4

Sucrosic dolostone, arenaceous dolostone

Uncommonly rippled or cross stratified

Subtidal shelf

<~60 (cps)

5

Poorly sorted arkosic sandstone, abundant accessory minerals

Dewatering structures, load casts and burrows

“event bed”, rapidly deposited unsorted sediment on the tidal flat

>~250 (cps)