Chapter 2 4.1 Flashcards
What are the tectonic processes that have influenced the U.K. in the past?
The plate on which the U.k. is on sifted sideways away from the tropics
Convection currents beneath the plate uplifted rocks from beneath the sea becoming land.
During uplift some rocks snapped and moved along faults in a series over thousands of years.
This happened over 300 million years ago 3 tectonic processes affect rocks in the pennies. These processes happen on the collision plate margin.
Why are there fossils in Malharn Cove that are just like the coral species found in the Great Barrier Reef? Geology part 1
Geologists know that fossils at Malharn Cove are just like the coral species living in the Great Barrier Reef. By testing fossils from Malharn Cove using carbon dating, they know that they lived during a geological period 250 to 350 million years ago.
What does hard rock consist of?
Hard rock consists of resistant rocks, such as igneous rocks, igneous granite and resistant sedimentary rock e.g. limestone.
What does soft rock consist of?
Soft rock consists of less resistant rock such as clays and shales which are more easily eroded. Examples include Holderness Coast (East Yorkshire), Christchurch Bay (Dorset and Hampshire.
Geology part 2
At the time the U.K. was covered by tropical Seas, tropical fish and corals thrived. As they died their skeletons fell to the sea floor forming strata two processes turned them into solid rock
- as skeletons fell they crushed those beneath eventually squeezing out water and complying the rock
- calcium carbonate crystallised around the fragments. This cemented them together and even persevered the fossils intact.
Glaciation part 1
As the pennies were uplifted, rivers like the Wharf eroded them, creating V-Shaped valleys. But the most recent Ice Age over 10,000 years ago brought huge glaciers to the Pennines.
What are the two effects that glaciation had on the Pennines?
The two effects are:
- altering river valleys, making them deeper and widening them into U-Shaped troughs.
- as they melted, the glaciers left features like Malhom Cove with a spectacular waterfall.
Give a definition, approximate age, 3 examples and location in UK of sedimentary rocks
Sedimentary rocks are made up of pieces of older rocks. The process has several stages: weathering, erosion,
transportation and deposition and cementation. Sedimentary rocks are porous meaning that water can get into cracks in the rocks. Examples of sedimentary rocks are chalk, clay and limestone. A location you can find these rocks in the UK is the North Downs.
Explain when and how active volcanoes shaped the uplands of the UK
Around 520 million years ago the land that now makes up the UK used to much closer to a plate boundary than it is now. Active volcanoes forced magma through the Earth’s crust which formed igneous rocks eg granite, these rocks were then eroded by rain until only the peak(the highest point) was left at the top of the mountain that was formed by this process.
Give a definition, approximate age, 3 examples and location in UK of igneous rocks in the UK?
Igneous rocks are created by volcanic activity when magma or lava cools, forming rocks made of crystals that are usually hard. Granite, Basalt and Obsidian, you might find these rocks in the Giant’s Causeway. These rocks are about 50 million years old.
Compare metamorphic and sedimentary rocks?
Sedimentary rocks are older than metamorphic rocks, as sedimentary rock such as mudstone are required to form metamorphic rocks such as slate. Both types of rocks need to be compacted before they become the different rock types that they are now. Both rock types are formed when the rocks are either compacted together or changed by heat and pressure. Clay is a sedimentary rock and is easily eroded, slate is a metamorphic rock that is very hard and resistant to weathering.
Compare the formation and characteristics of granite and carboniferous limestone?
Granite forms in upland landscapes and carboniferous limestone also forms in upland landscapes, granite is impermeable (meaning it doesn’t let water through it) and carboniferous limestone is permeable (meaning it does let water through it).
Explain how glacial deposition shaped the UK lowlands
- during the last ice age large amounts of material such as clay and chalk.
- these than got compacted and the chalk froze
- the ice then melted and became water and help to form valleys and rivers.
Compare the formation and characteristics of chalk and slate?
Chalk forms in escarpments (hills) in UK lowlands and cliffs at the coast. Slate forms in layers creating weak planes in the rock. Chalk is a permeable rock whereas slate is an impermeable rock.
Explain when and how sedimentary rock was formed across the UK Lowlands
Around 30 million years ago, large earth movements caused compacted layers of sediment to be forced upwards, cresting a big, chalk covered dome called an anticline. Over time, the dome experienced erosion, which removed the chalk at the centre of the dome, leaving two escarpments either side. Between these two escarpments were the chalk has been eroded sandstone and clay have been exposed and are no longer compacted under the ground.
