Geology Flashcards
How are sedimentary rocks formed, give 2 examples?
Layers of sediment, small particles that have been eroded
Limestone, sandstone
What is the material that makes limestone?
Skeletons deposited under a warm ocean
What material makes sandstone?
Sand from rivers
How are extrusive igneous rocks formed?
Lava which turns into basalt when cooled
What kind of crystals do extrusive igneous rocks have and why?
Fine grained crystals as extrusive rocks cool down quickly
How are intrusive igneous rocks formed?
Forms within the crust
What kind of crystals do intrusive igneous rocks have, why?
cool slowly creating large crystals
What contact metamorphism?
Rocks underground come in contact with heat (magma), the magma burns the rock, changing the rock into a different rock
What causes regional metamorphism and where is it found?
Caused by pressure
Usually found at destructive plate boundaries
Whats one evidence for glaciers?
U shaped valley- valley with steep sides and flat valley floor created by erosion so processed of a glacier
How have metamorphic rocks been changed?
Through heat and pressure, and often show layers or bands of minerals
How do u shaped valleys form?
Formed by glacial plucking, which freezes rocks, and abrasion, which grinds and deepens the valley as the glacier moves
How do fossils form in sedimentary rocks?
Sediment layers bury plants and animals, which over time become compacted and cemented into rock, preserving their organisms and enabling scientists to study past life forms and environments.
How did the ice age affect sea levels in the uk?
During the ice age, glaciers cause sea levels to drop significantly. As ice melted, sea levels rose, flooding low-lying areas and forming features like river valleys and coastal plains
What is the difference between upland and lowland landscapes in the uk?
Upland- typically made up of igneous and metamorphic rocks, which are harder and form mountainous terrains
Lowland- sedimentary rocks which are softer and flatter, less elevated areas
How do glacial processes contribute to landscape development?
Shape the landscape by carving valleys, creating land forms like drumlins, and depositing sediment in lowlands
What types of erosion and weathering are common in the UK’s upland areas?
Mechanical weathering (such as freeze-thaw) and chemical weathering (like carbonation of limestone) are common. Erosion by glaciers and rivers also shapes the landscape, carving valleys and fjords.
Which rock types are most resistant to weathering and why?
Igneous and metamorphic rocks are more resistant to weathering due to their dense, crystalline structure
Sedimentary rocks are prone to weathering as they are often softer and contain pores that allow water to penetrate
What is freeze- thaw weathering and how does it contribute to the formation of scree?
Occurs when water enters cracks in rock, freezes, and expands, causing the cracks to widen. This process, repeated over time, breaks the rock apart, forming a scree slope (a pile of loose rock debris) at the base of cliffs
What is the general pattern of rock distribution across the uk, and are there any exceptions?
General pattern: upland areas dominated by hard igneous and metamorphic rocks while lowlands areas are made up of softer sedimentary rocks
Exceptions: some lowland areas like Weald in southern England, have igneous or metamorphic rocks due to ancient tectonic activity
How do geological processes shape the uk’s coastal landscapes?
Shaped by erosion (e.g. cliff erosion from waves) and deposition (e.g. sandbars and beaches)
Harder rocks tend to form rugged coastlines, while softer rocks like clay erode more quickly, leading to features like bays and coves
How do tectonic processes contribute to the formation of upland landscapes?
Plate movements can cause the Earth’s crust to buckle, fold or fracture, leading to the formation of mountain ranges and upland areas
Suggest one way Corrie formed by glacial erosion has been modified by recent weathering?
Since the glaciers melted, the rocks in this area will have been weathered by freeze-thaw weathering. In the winter temperatures fall, causing water in cracks to freeze, and expand. Alternating freezing and thawing loosens and breaks the rocks to create scree slopes.
Suggest one post glacial process that has formed the valley (talk about ribbon lakes)?
Glaciers have decreased in size and strength due to weather changes, glaciers create ribbon lakes that follow the shape of the valley, the sediment carried by the glacier would be deposited.
