Table of Contents
- 1 What are parallel scratch marks on bedrock called?
- 2 What is called the plucking?
- 3 What is the difference between striations and grooves?
- 4 What is striated rock?
- 5 What is the most immediate and visible evidence that a Valley has been occupied by a glacier?
- 6 What are rocks left by glaciers called?
- 7 What are the elements that make up bedrock?
- 8 How big are the veins in the bedrock?
What are parallel scratch marks on bedrock called?
Glacial striations are a series of long, straight, parallel lines or grooves scratched onto a bedrock surface by rock fragments lodged in the base of a moving glacier. They typically form on hard rock, such as quartzite, that is relatively resistant to erosion.
What is called the plucking?
Plucking, also referred to as quarrying, is a glacial phenomenon that is responsible for the erosion and transportation of individual pieces of bedrock, especially large “joint blocks”. As a glacier moves down a valley, friction causes the basal ice of the glacier to melt and infiltrate joints (cracks) in the bedrock.
What are glacier scars?
Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. Glacial striations are usually multiple, straight, and parallel, representing the movement of the glacier using rock fragments and sand grains, embedded in the base of the glacier, as cutting tools.
What are the scratches called that are left behind when glaciers have moved through an area which can give clues to the direction that the ice moved in?
As ancient glaciers flowed over basalt at Devil’s Postpile National Monument (California), rock and sediment in the ice left scratches on the bedrock. These scratches, “striations,” can be used to understand past ice flow. This rock has been scratched so much it shines with “glacier polish.”
What is the difference between striations and grooves?
is that groove is a long, narrow channel or depression; eg, such a slot cut into a hard material to provide a location for an engineering component, a tyre groove, or a geological channel or depression while striation is (countable|mineralogy) one of a number of parallel grooves and ridges in a rock or rocky deposit.
What is striated rock?
Striations are lines or scratches on rock surfaces, usually no more than a few millimeters in depth, produced by the process of glacial abrasion (Glasser and Bennett, 2004). From: Developments in Earth Surface Processes, 2015.
Which comes first plucking or abrasion?
Plucking occurs when rocks and stones become frozen to the base or sides of the glacier and are plucked from the ground or rock face as the glacier moves. This leaves behind a jagged landscape. Abrasion occurs when rocks and stones become embedded in the base and sides of the glacier.
What is an example of plucking?
plucking petals off a flower Firefighters plucked the child from the top floor of the burning building. He’d been plucked from obscurity and thrust into the national spotlight. a cat that was plucked off the city’s streets last winter He plucked a stone out of the river. Noun It takes pluck to do what she did.
What is the most immediate and visible evidence that a Valley has been occupied by a glacier?
Grains of rock embedded in the ice grind against the bedrock. What is the most immediate and visible evidence that a valley has been occupied by a glacier? The valley is quite straight with a broad bottom, and is U shaped. Weight of ice sheets depresses the crust; after melting, crust rebounds and rises.
What are rocks left by glaciers called?
Glaciers can pick up chunks of rocks and transport them over long distances. When they drop these rocks, they are often far from their origin—the outcrop or bedrock from which they were plucked. These rocks are known as glacial erratics.
How do Kames and eskers differ?
Kame: a mound-like hill of ice-contact stratified drift. Kames are formed when sediments lodged in crevasses in or on the surface of stagnant ice are deposited when the ice melts away. Esker: a long narrow ice-contact ridge. Eskers are usually sinuous and are composed of stratified drift.
Is striation erosion or deposition?
With the weight of the ice over them, these rocks can scratch deeply into the underlying bedrock making long, parallel grooves in the bedrock, called glacial striations. Glacial striations point the direction a glacier has gone. Mountain glaciers leave behind unique erosional features.
What are the elements that make up bedrock?
Solid bedrock is under continual attack by elements of the atmosphere, hydrosphere, and biosphere. The sum of these processes is called weathering. During weathering the chemical elements that make up the original bedrock may behave very differently.
How big are the veins in the bedrock?
Quartz veins within the bedrock did not protrude more than 1 cm from the surface, indicating that there has been little postexposure lowering of the more erodible rock fractions.
Is the bedrock under continual attack by elements of the atmosphere?
C.G. Patterson, D.D. Runnells, in Encyclopedia of Physical Science and Technology (Third Edition), 2003 Solid bedrock is under continual attack by elements of the atmosphere, hydrosphere, and biosphere. The sum of these processes is called weathering.