4.1 Flashcards
Role of geology
Is to evolve landscapes. Geologists study Earth processes: Many processes such as landslides, earthquakes, floods, and volcanic eruptions can be hazardous to people. Geologists work to understand these processes well enough to avoid building important structures where they might be damaged.
Glacial processes
Glacial Erosion. There are two main processes of glacial erosion. The first that we will talk about is plucking, which is defined as the erosion and transport of large chunks of rocks. As a glacier moves over the landscape, water melts below the glacier and seeps into cracks within the underlying bedrock.
Tectonic proceeses
Tectonic processes mostly take place at the plate edges. A plate moves as a single entity along the surface of the Earth over a plastic mantle. There are two types of plate: Oceanic plates form at the mid-ocean ridges
Upland
These classifications overlap with the geological definitions of “upland” and “lowland”. In geology an “upland” is generally considered to be land that is at a higher elevation than the alluvial plain or stream terrace, which are considered to be “lowlands”
Lowland
lowland. land that is low or level, in comparison with the adjacent country. the Lowlands, a low, level region in S, central, and E Scotland. Lowlands, the speech of those native to the Scottish Lowlands.
3 examples of igneous rock and location in uk
basalt
obsidian
pumice
The youngest rocks are 50 million year old basalt. Located up in high lands.
Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth’s surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate.
Give a definition, approximate age, 3 examples and location in UK of sedimentary rocks
Sedimentary Rocks in Britain. Sandstone hills in the northwest Highlands, around 700 million years old. Sandstone layers folded to form an anticline, SW Wales. Mudstone cliffs on the Yorkshire coast, formed in the sea almost 200 million years ago
breccia, conglomerate, sandstone
Compare metamorphic and igneous rock
Minerals make up rocks. … Igneous rock , formed by the cooling of magma (molten rock) inside the Earth or on the surface. Sedimentary rocks, formed from the products of weathering by cementation or precipitation on the Earth’s surface. Metamorphic rocks, formed by temperature and pressure changes inside the Earth.
Igneous rock is a lot harder
Compare the formation and characteristics of granite and carboniferous limestone
Granite a very hard, granular, crystalline, igneous rock consisting mainly of quartz, mica, and feldspar and often used as a building stone.
Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). About 10% of sedimentary rocks are limestones.
Compare the formation and characteristics of chalk and slate
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
Explain when and how active volcanoes shaped the uplands of the UK
Volcanoes form when magma reaches the Earth’s surface, causing eruptions of lava and ash. They occur at destructive (compressional) and constructive (tensional) plate boundaries.
The immediate effects of volcanic eruptions can be devastating, but they may be beneficial in the long term.
Explain how glacial erosion and deposition shaped the UK uplands
The base of glacier ice melts because of pressure and friction. This allows water to freeze into cracks in the rocks and when the glacier moves it pulls out chunks to leave a jagged surface.
This provides material for abrasion and this process is called plucking. Rocks which get stuck in the ice grind away the bedrock under the glacier and this is known as abrasion.
Freeze thaw, or frost shattering, is a process of weathering that also occurs in upland areas. Water in cracks in the rock freezes and expands, forcing open the gap. When the ice melts more water can get into the crack and freeze again.
After many cycles of freezing and thawing lumps of rock are broken off the surface - this is called freeze thaw. These small pieces of rock are called scree and often build up forming scree slopes on mountainsides.
Explain when and how sedimentary rock was formed across the UK Lowlands
Sedimentary rocks were formed due to the compaction of mud and other material over time
Explain how glacial deposition shaped the UK Lowlands
Plucking - the glacier pulls out chunks of rocks to leave a jagged surface. This provides material for abrasion.
Abrasion - rocks stuck in the ice grind away the bedrock under the glacier.
Freeze thaw - Freeze thaw weathering/frost shattering is a process of weathering that also occurs in upland areas. water in cracks in the rock freezes and expands forcing open the gap. When the ice melts more water can get into the crack and freeze again. After lots of freezing and thawing lumps of rock are broken off the surface. These small pieces of rock are called scree and often build up forming scree slopes on mountainsides
Explain how scarp and vale topography forms in the UK Lowlands
Scarp-and-vale topography A landscape consisting of a roughly parallel sequence of cuestas (scarps and dip slopes) and intervening valleys (‘vales’). It is typically found on uniclinal (homoclinal) structures whose beds show differing lithological composition and consequently varied resistance to denudation. It dominates most of lowland Britain, which is characterized by Mesozoic sediments dipping gently towards the east and south-east.
