G1-Lecture08-FormationofSoils

G1-Lecture08-FormationofSoils - CEG CEG-4011 Geotechnical...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CEG CEG-4011 Geotechnical Engineering 4011 Geotechnical Engineering Lecture Lecture #08 #08 The Formation of Soils Luis A. Prieto-Portar 2009 The products of weathered rocks may stay in the same place, in which case they are called residual soils. If the soils are moved to other locations by rivers, ice, wind and gravity, in which case they are called transported soils . Residual Soils. Residual soils are those that have weathered at their original rock and remained at their origin. If the soil retains the characteristics of the structure of the parent rock, it is called a sapprolite (from the Greek & = putrid + & =soil). This soil profile in Hong Kong shows the parent granite at the bottom and increasing degrees of weathered soil towards the top of the photo. The top layer is the sapprolite . The humid, subtropical climate of Hawaii decays the parent Andesite igneous rock into a Saprolite. This 15 feet thick Saprolites retain much of the parent rocks texture. Areas with the heaviest rainfall may produce strata over 300 feet thick. Limestone The soils of the Continental United States. P. Mion, NGS Cartographic Division, National Geographic, Sept. 1984. Soil profiles of the four most common soil types in the United States. This aridisol is was excavated at a road construction site in the Texas High Plains region. It shows that the topsoil is still fertile but shallow. Below the red topsoil is the grey cemented lime, called caliche which can only be broken up with dynamite. arming becomes impossible Farming becomes impossible when the topsoil is eroded or if it is too shallow and exposes the caliche. (National Geographic, Sept. 1984). Transported Soils. Transported soils are classified according to the mode of transport and deposition into one of these groups: 1.- Glacial soils , are the products of erosion and deposit by glaciers; 2.- Alluvial soils , are transported and deposited by steams and rivers; 3.- Lacustrine soils , are the deposits in lakes; 4.- Marine soils , are the various deposits from wave action, or currents in oceans and seas; 5.- Aeolian soils , are deposits from wind transportation; 6.- Colluvial soils are rapidly deposited soils via gravity in the form of mudslides or landslides. Glacial Soils. The general term drift is applied to all deposits that are laid down directly by glaciers. Drift is called till when un-stratified: composed of boulders weighing several tones to gravels, sands, silts, clays and colloidal particles all mixed up. The deposits of till produce topographical features called moraines and drumlins ....
View Full Document

Page1 / 50

G1-Lecture08-FormationofSoils - CEG CEG-4011 Geotechnical...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online