1 / 13

Geological assignment

Geological assignment. Compiled by: SUKHWANT MOHAN ABHISHEK ARYAN. CONTENT. Geological work by river. ABOUT THE GEOLOGICAL WORK

lydia
Download Presentation

Geological assignment

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Geological assignment Compiled by: SUKHWANT MOHAN ABHISHEK ARYAN

  2. CONTENT

  3. Geological work by river

  4. ABOUT THE GEOLOGICAL WORK When a piece of the Earth’s crust first emerges from the sea and rain begins to fall on it, the water running off begins to erode it. As the first gullies develop into channels, the drainage of this new land gets organized by an interplay of two principle factors: differential erosion & stream capture.

  5. DIFFERENTIAL EROSION • As the water runs down hill, it erodes channels that become organized into a drainage pattern. As running water deepens its channel, it encounters rocks of different hardness and adjusts its channel in response. Soft layers erode faster than hard layers. This simple statement is an important principle of erosion which that applies to almost every natural scene. Eventually, hard layers or other hard parts of rocks stand out in bold relief, and softer layers or parts retreat into swales, gullies, and valleys. Geologists call the process differential erosion.

  6. STREAM CAPTURE • Stream capture or piracy, is the process whereby a stream easily deepening its valley in soft rock can cut headword across a drainage divide to capture a portion of a neighbouring stream that is working away slowly in harder rock. Examples of pure stream capture are hard to find in the North Cascades because of the overriding disruption of drainages by the growth and retreat of the Canadian Ice Sheet, but the overall parallel conformity of most North Cascade streams and rivers to the northwest-southeast-trending structural grain, indicates stream piracy has ruled for millions of years. The figure above, representing an idealized situation, illustrates the process.

  7. INTRODUCTIONOFSTREAM

  8. ABOUT STREAM • Streams alter the Earth's landscape through the movement of water and sediment . Streams are powerful erosive agents moving material from their bed and banks. In mountainous regions, stream erosion often produces deep channels and canyons. Streams also deposit vast amounts of sediment on the terrestrial landscape and within lakes and ocean basins.

  9. TYPES OF STREAMs • CONSEQUENT STREAM:- In any area these are the first stream to have developed in accordance with the topography of the area. • SUBSEQUENT STREAM:-These are the generally tributaries to the consequent streams. The characters of the rocks over which they flow controls their direction of flow • OBSEQUENT STREAM:-These are tributaries to the subsequent streams. In most cases their direction of flow may be opposite to the main or consequent stream. • INSEQUENT STREAM:-They may also be called irregular stream. These are found to flow in canals that show no well defined relationship with either the slope of the area or the character of the rocks.

  10. INTRODUCTION Of DRAINAGE SYSTEM

  11. DRAINAGE SYSTEM • A drainage system is the pattern formed by the streams, rivers, and lakes in a particular drainage basin. They are governed by the topography of the land whether a particular region is dominated by hard or soft rocks, and the gradient of the land. Geomorphologists and hydrologists often view streams as being part of drainage basins. A drainage basin is the topographic region from which a stream receives runoff, through flow, and groundwater flow. Drainage basins are divided from each other by topographic barriers called a watershed.

  12. Types of drainage system • TRELLIS DRAINAGE:-When a consequent stream receives a number of subsequent stream from right and left at approximately right angles to its direction of flow, a trellis drainage system is said to develop. • DENDRITIC DRAINAGE:-This type of drainage system develops when the strems of different types are all fairly common in a region and none a pairs to dominate other group. • RADIAL DRAINAGE:-This type of drainage system develops in a region which are either elevated or depressed with reference to the surroundings topography. • SUPREMEPOSED DRAINAGE:-It is developed in geologically old and complex folded region. • ANTECEDENT DRAINAGE:-Gradual uplift of the crystal blocks forming the mts system is believed to be a well-established geological phenomenon.

  13. THANK YOU

More Related