Fluvial through "deep" lacustrine transitions are present in the Green River Formation (Eocene) of the Uinta basin, Utah. Characteristic sedimentary features useful for reconstructing specific subenvironments are (in approximate order of usefulness):

Fluvial Channel:
Small- and medium-scale cross-stratification; horizontal stratification; channels; poorly sorted sublitharenite, lithic arenite and subarkose; intraformational and chert-pebble conglomerate.

Fluvial Floodplain:
Earthy silty claystone; paleosoil.

Lagoonal:
Thin horizontal lamination; waxy claystone; clastic lenses of oolitic sandstone; algal mat; carbonate pebble conglomerate.

Shoal:
Horizontal and small- to medium-scale cross-stratification; oolite; algal mat; ripple marks; shrinkage polygons; chert-pebble conglomerate; ripple stratification; bone fragments.

Beach, Shoreface:
Horizontal and small- to medium-scale cross-stratification; quartz-arenite and subarkose; ripple marks; incomplete shrinkage cracks; ripple stratification; burrowing; chert-pebble conglomerate; large-scale cross-stratification; disturbed bedding; small channels.

Nearshore:
Horizontal and wavy stratification; fine-grained sandstone and siltstone; small-scale cross-stratification; disturbed bedding; incomplete shrinkage cracks; ripple marks; ripple stratification.

Offshore:
Horizontal stratification; varves; oil shale and claystone; syneresis cracks; oolitic sandstone; stromatolites.

Sedimentary cycles are present in each of these depositional environments. Lacustrine cycles consist of a lower regressive clastic phase and an upper transgressive carbonate phase. Specific lithologies and sequences differ in each lacustrine subenvironment. Fluvial cycles consist of a basal erosional episode followed by channel filling and floodplain development. Fluctuations in the level of Lake Uinta are interpreted to have caused these cyclical deposits.

End_of_Article - Last_Page 343------------