• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Geological changes - revision notes

Extracts from this document...

Introduction

* Weathering * Rocks * Earth's Structure Tina Doyle Weathering There are 3 main types of weathering: Physical, Chemical and Biological. * Freeze-thaw weathering - this occurs when rain water seeps into cracks in rocks and if the temperature drops below freezing, the water turns to ice and expansion pushes the rocks apart. This keeps happening each time the water thaws and refreezes. Eventually bits of the rock break off. * Acid rain - this is caused by pollution from the burning of fossil fuels being dissolved in it. Limestone is a very alkaline rock so it is quickly attacked by any acid. It also contains a lot of calcium carbonate. This dissolves in cold rain water to make calcium hydrogen carbonate solution. This reaction is shown in the equation below: Calcium carbonate + Carbonic acid Calcium hydrogen carbonate solution As rain water trickles through cracks in the limestone over many years it can dissolves millions of tonnes of rocks to make huge caves. ...read more.

Middle

Weathering breaks rocks, erosion wears them away. Rocks Rocks There are 3 main types of rock: Igneous (intrusive & extrusive), Sedimentary and Metamorphic. Name of Rock Type How it's type is made How we recognise the rock by observation Basalt Igneous Formed underground by lava flow dark-coloured (black to medium-grey) Mudstone Sedimentary Formed from mud Often dark grey, splits into layers easily Marble Metamorphic Metamorphosed limestone and chalk Very hard Limestone Sedimentary Composed almost entirely of calcium carbonate Hard, solid rock Granite Igneous Formed underground when magma cools down Hard, coarse and grained Slate Metamorphic Metamorphosed shale Very hard black layered rock Sandstone Sedimentary Made of sand-sized particles Red or yellow Fossils are only found in Sedimentary rocks, because these rocks have been crushed for millions of years, so the fossils can survive. ...read more.

Conclusion

* Volcanoes - these appear in some areas when tectonic plates move apart. Magma rises up to fill the gap and produces new crust made of basalt. Sometimes it comes out with great force, producing volcanoes. Rock Record The rock record, (type, magnetic and fossil) shows the sequence of and evidence for geological changes. Rock layers are also called strata (the plural form of the word stratum), and stratigraphy is the science of strata. Stratigraphy deals with all the characteristics of layered rocks; it includes the study of how these rocks relate to time. Strata, or compacted layers of sediment, deposited in the sedimentary basins of New Zealand provide the raw data from which much of geological history is deduced. Conditions of deposition, the 3-dimensional shape and the distribution of layers of sedimentary rocks are the subject of current research. Much of this work is oriented to exploration for hydrocarbons and other energy resources. ?? ?? ?? ?? ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Rocks & Weathering section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related AS and A Level Rocks & Weathering essays

  1. My aims are to investigate the factors affecting Lava Flows.

    If they're any anomalies redo them. Diagram Results This table shows how long it takes for wallpaper paste to flow down a 50-cm slope of 30 degrees and it shows the speed. The Viscosity in the table stands for the amount of wallpaper powder used.

  2. Rock types.

    Limestone (a base) reacts with acid to make salt and water in a neutralisation reaction. * When heated in a furnace, it breaks down to quick lime (calcium oxide) and carbon dioxide as metal carbonates decompose on heating. Quick lime (Calcium oxide)

  1. Determining the paleoenviroment and tectonic history of a small area (Cocklawburn Beach)

    most of the information that I have gathered on the trip that will be useful in a clear way Analysing evidence and drawing conclusions From the sedimentary logging sheet there is a obvious pattern in the rock layers, which clearly show the recurring cyclotherms, I believe that I was caused

  2. 'I think that sedimentary stones will be more affected by weathering than igneous stones.' ...

    - Also the stones are dated making it very easy to grade the stones by age and compare stones of similar ages. - Furthermore there are different stones in different circumstances (some in shelter), meaning I can have a wide range of data because they are not all the same.

  1. A Geological Report on the Permo-Triassic of Chester.

    'Lower mottled sandstone' which can be occasionally mottled with white and yellow patches. This is recognised as 'millet seed' and is wind worn sand grains. The area also has a large domination of gravely aggregates intermingled by pebble beds of yellow stone, that are in certain locations bedded.

  2. Construct two Graphic Log Sections, one on the eastern exposure (ST 3375 6645) and ...

    The minerals eg calcite or quartz are derived from fluids and are deposited in faults or fractures. 18 Basalt, dark in colour. Pillow lavas Pillow lavas formed underneath the surface of water and near a volcano where magma is produced.

  1. Compare and Contrast the Weathering Found in an Area of Limestone Country with that ...

    An example of a dry valley is Incombe Hole, Chilterns. Dry valleys occurred after the end of the ice age. They were formed when the limestone was frozen therefore making it impermeable. When the ice melted it carved out valleys in the frozen rock, but when the limestone thawed out,

  2. Investigate the relationship between the solid geology and the physical landscape from Ingleton to ...

    This is due to the two faults close by, which has interrupted the original position of the limestone. At this point the fold of the limestone dips quite sharply, towards the bed of the River Twiss. These damp shaded conditions provide the ideal environment for ferns to survive.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work