Cambrian System of the Grand Term Paper

SAMPLE EXCERPT . . .
Berkhault (2004) states that, "Because the Tapeats, Bright Angel, and Muav are not separated by unconformities but grade into each other, they have been collectively called the Tonto Group. The deposits are overlain by the sequence of sandstones, siltstones, shales, and carbonate rocks of Devonian, Carboniferous and Permian Systems."

IV. Zones in the Tonto Group Strata

The Tapeats, Bright Shale Angel and Muav Limestone "superposed each other and juxtaposed when erosion produced clasts of all sizes, including particles of quartz, clay, pebbles and boulders. As indicated by Lebediev (1959) the velocity of incipient motion relative to the depth of water was in relation to the clast size. As the advancement of the transgression occurred the water increased in deepness which resulted in a reduction of the current but still a capacity to erode remained causing clasts that were smaller than boulders and were transported as far away as Zone 2.

Zone One & Two

The shallow zone or Zone 1 experienced current that was greatly 'diminished' (Berkhault, 2004) and the erosion level was diminished as well but transported 'clasts of terrigeneous which is grave, sand, silt and clay as well as carbonate material such as lime. Berkhault (2004) states that, "A regressive current started, which carried westwards the largest particles in a bed load, and the smallest in a suspended load. The first deposited from zone 2 to 6, and the second in zones 5 and 6 only."

Zone Three

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for only $8.97. Characterized in composition by sand in waves that were formed by thin cross sand beds, this zone is composed of sand waves forming thinly cross-bedded sands, which compose the middle of the Tapeats. Water velocity was approximately 1.0 meter per second.

Zone Four

The waters with the most depth and least velocity "depositing the uppermost Tapeats" (Berkhault, 2004)

Zone Five

Term Paper on Cambrian System of the Grand Assignment

This zone is characterized by deposits formed by much deeper waters and much slower in motion with the silicate clay and particles that were silt sized accumulated forming the graded silt and clay beds of Bright Angel Shale with water velocity at approximately 0.5 meters per second.

Zone 6: This zone is farther towards the west and is the water with the most depth and the water that moved the slowest of all waters at the time characterized by a deficiency of particles of silicate clay and silt-sized. Lime mud accumulated in strata that is laminated and bedded "rhythmically" and water velocity was below 0.5 meters per second.

Summary

The lower middle and upper series in the stratigraphic scale of the Cambrian is a duration of over 50 million years but the three faceis of the Tonto group deposited simultaneously appear super and juxtaposed which could be explained due to a varying velocity of the water flow in the different zones while sedimentation was still in its' formation process.

References

Berthault, G., Analysis of main principles of stratigraphy on the basis of experimental data / / Lithol. Polezn. Iskop., 2002, no 5, pp. 442 -- 446.

Timmons, Mike et al. (1999) Grand Canyon Supergroup Six Unconformities Make One Great Unconformity A Record of Supercontinent Assembly and Disassembly BQR ~ winter 1998-99 Online available at: http://gcrg.org/bqr/12-1/supergroup.html

Lebedev, V.V., Gidrologiya I gidravlika v mostovom dorozhnom stroitel'stve (Hydrology and Hydraulics in Bridge and Road Building), Leningrad: Gidrometeoizdat, 1959. 384 c.

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