Lamins, Silt

Test borings revealed that the fill material consists predominantly of thinly laminated silt with a relatively high clay content. Occasional discontinuous layers of fine sand were encountered at random locations, both horizontally and vertically. The water table gradient under nonpumping conditions was toward the canal with an approximate gradient of 0.011 ft/ft. Slug tests indicated an effective permeability of 1 x 10-5 cm/s. 

CH Channel + levee Trough cross-bedded sand (St) planar laminated sand (Sp) low angle cross-bedded sand (SI) horizontally laminated sand (Sh) ripple cross-laminated sand (Sr) massive sand (Sm) massive, crudely bedded silts and muds (Fm) finely laminated to rippled silts and muds (FI) laminated silt, sand, and clay (Fsc) Tabular to lenticular 0.2-3 m thick 10 m to >2 km in lateral extent Fine to coarse, moderately sorted sand/sandstone Type 1 and type 3 (phreatic) tabular units... 

Varve or rhythmites chronology is another approach based on the examination of geological materials. In this model, the distribution of the laminated sediments formed in the bottom of the beds of dried-out lakes (as a consequence of the seasonal melting of glaciers and the subsequent deposition of coarse particles supplied by streams, followed by finer materials such as sand, silt, and clay) is analyzed and correlated with climate changes [64],... 

The black layer is a 3.5 cm thick, black to very dark gray clayey silt with weak lamination. The most notable feature of this layer is the abundance of euhedral, starburst shaped Mn oxide minerals that average 0.5 to 0.1 mm in diameter (Figs. 4E and 4F). The detrital component of this unit is dominated by quartz silt. The upper contact of this unit is slightly eroded and marked by clay clasts and a transition to red laminated clay. 

The Cleveland Member consists primarily of black to brownish-black laminated siliceous shale. It contains minor amounts of calcareous laminae and cone-in-cone limestone. Pyrite is present as nodules, framboids, and irregular forms. Other primary minerals include illite clay and clay- and silt-size quartz. 

The overall depositional environment of the Middle Lunde Member represents a distal alluvial plain or terminal basin (Nystuen et al 1989 Steel Ryseth, 1990 Nystuen Fait, 1995). Depressed areas were flooded by ephemeral sheet floods, leaving blankets of sand, silt and mud of high lateral extent. During certain periods these depressions could turn into shallow temporal lakes in which laminated, current-ripple laminated and wave-ripple laminated mud and silt aggraded. Drying up of these shallow lakes gave rise to frequent desiccation cracks, distorted lamination and mud flakes. The episodic flooding promoted the infiltration of suspended clay particles into the sand blankets. 

Shale A rock formed by consolidation of clay, mud, or silt, having a laminated structure and composed of minerals essentially unaltered since deposition. 

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