weathering by ali

Weathering : 

Weathering Weathering is the breakdown of rock “in situ” (where it is) Erosion involves taking away and further breaking down rock as it moves. There are four main agents of erosion Rivers (fluvial), Sea (waves), Glaciers, Wind Task: Use this presentation as a base to add your own text and diagrams when asked for. When you have finished upload it to a share site such as slideshare or authorstream, get the embed code and place it in your eportfolio.

Types of Weathering : 

Types of Weathering Physical Chemical Biotic Freeze-Thaw Exfoliation (onion-skin) Carbonation oxidation Plant roots Animals burrowing

Freeze-Thaw : 

Freeze-Thaw Explanation: freeze-thaw occurs in cold climates when temperatures are around freezing point and where exposed rock contains many cracks. Water enters the cracks during the warmer day and freezes during the cooler night. As water turns into ice it expands and exerts pressure on the surrounding rock. When temperatures rise, the ice melts and pressure is released. Repeated freezing and thawing widens the cracks and cause pieces of rock to break off.

Exfoliation (Onion skin) : 

Exfoliation (Onion skin) Description and Explanation: Occurs in very warm climates when exposed, non-vegetated rock is repeatedly heated and cooled. The surface layers heat up and expand more rapidly during the day and cool and contract more rapidly at night then do the inner layers. This sets up stresses within the rock which cause the surface layers to peel off, like layers of an onion.

Biological : 

Biological This is when the roots of plants break up rocks as they grow. Burrowing animals can also break up the soil and rocks. Snails also have an effect. Just look at the trails they leave on walls. The main impact is that by aerating the soil they allow other agents to directly weather the parent rock which is under the soil. The breakdown of dead plants also releases an acid called humic acid and this is important in the breakdown of rock. This occurs especially in hot humid tropical areas, however it is normally associated with Chemical Weathering.

Chemical : 

Chemical 1. Oxidation is when oxygen in the air reacts with chemicals in the rock. The most important is when iron in rocks in one form called ferrous oxide (FeO) combines with oxygen to form the soluble Ferric oxide (Fe2o3). This is basically rust and leads to red soils. This happens a lot in tropical areas also.

Carbonation – Limestone areas : 

Carbonation – Limestone areas Describe and explain the situation here:

Climate and Weathering : 

Climate and Weathering At Barbados the yearly average temperature is 26.00C (78.8F). 21.00C (69.80F) is the coldest monthly average low temp (that comes about in January, February, March) while 30.00C (86.00F) is the hottest monthly mean max temp transpiring in the month of April, May, June, July, August, September, October. The mean temperature range is 2.50C. Rainfall/ snowfall etc. in Barbados accumulates to give us a mean total of 1413.00mm (55.63in) per annum. This is equivalent to average monthly precipitation of 117.75mm (4.64in). October, November is the most damp month effected by an average of 201mm (7.91in) of water precipitating on an average of days while in March only 40mm (1.57in) of rain falls over 12 days. Barbados’s climate receives 190 days per year with greater than 0.1mm (0.004in) of rainfall.

Next : 

Next We will be looking at the limestone landscape of Barbados and comparing it to other limestone landscapes worldwide. What is the role of limestone in shaping some of the features we have Caves, underground streams, gulleys, Humans and the limestone environment