Surfactant Adsorption on Clay minerals Injection of aqueous surfactant solutions in porous media is a widely used technique for facilitating removal of organic fluids e. Some of the main applications are for improving i removal of organic contaminants from groundwater resources, and ii recovery of oil from hydrocarbon reservoirs. Clay minerals are one of the main constituents of naturally occurring porous rocks which form groundwater aquifers and hydrocarbon bearing formations. The amount and type of clay minerals impact the surface chemistry of the rock and hence influence adsorption of charged particles to the rock.
The western hemisphere is dominated by the Tharsis region red and brown. Tall volcanoes appear white. Valles Marineris blue is the long gash-like feature to the right. The Elysium province is at the upper right edge.
Areas north of the dichotomy boundary appear as shades of blue on both maps. The northern and southern hemispheres of Mars are strikingly different from each other in topography and physiography. This dichotomy is a fundamental global geologic feature of the planet. Simply stated, the northern part of the planet is an enormous topographic depression.
In contrast, the lowlands north of the dichotomy boundary have few large craters, are very smooth and flat, and have other features indicating that extensive resurfacing has occurred since the southern highlands formed. The third distinction between the two hemispheres is in crustal thickness.
The origin and age of the hemispheric dichotomy are still debated. Hypotheses of origin generally fall into two categories: A new theory based on the Southern Polar Giant Impact  and validated by the discovery of twelve hemispherical alignments  shows that exogenic theories appear to be stronger than endogenic theories and that Mars never had plate tectonics   that could modify the dichotomy.
Laser altimeter and radar sounding data from orbiting spacecraft have identified a large number of basin-sized structures previously hidden in visual images.
Called quasi-circular depressions QCDsthese features likely represent derelict impact craters from the period of heavy bombardment that are now covered by a veneer of younger deposits. Crater counting studies of QCDs suggest that the underlying surface in the northern hemisphere is at least as old as the oldest exposed crust in the southern highlands.
The vast Alba Mons formerly Alba Patera occupies the northern part of the region.
The huge shield volcano Olympus Mons lies off the main bulge, at the western edge of the province. As a result, immense extensional fractures grabens and rift valleys radiate outward from Tharsis, extending halfway around the planet. The Elysium volcanic complex is about 2, kilometers in diameter and consists of three main volcanoes, Elysium MonsHecates Tholusand Albor Tholus.
The Elysium group of volcanoes is thought to be somewhat different from the Tharsis Montes, in that development of the former involved both lavas and pyroclastics.
The largest one that is readily visible is the Hellas basin located in the southern hemisphere. Ancient, low-relief volcanic constructs highland paterae are located on the northeastern and southwestern portions of the rim.
The basin floor contains thick, structurally complex sedimentary deposits that have a long geologic history of deposition, erosion, and internal deformation. The northeastern portion of the basin rim has been eroded and is now buried by northern plains deposits, giving the basin a semicircular outline.
The northwestern rim of the basin is characterized by arcuate grabens Nili Fossae that are circumferential to the basin. One additional large basin, Utopiais completely buried by northern plains deposits. Its outline is clearly discernable only from altimetry data.
All of the large basins on Mars are extremely old, dating back to the late heavy bombardment. They are thought to be comparable in age to the Imbrium and Orientale basins on the Moon.
Equatorial canyon system[ edit ] Viking Orbiter 1 view image of Valles Marineris. Near the equator in the western hemisphere lies an immense system of deep, interconnected canyons and troughs collectively known as the Valles Marineris.
The Grand Canyon is largely a product of water erosion. The Martian equatorial canyons were of tectonic origin, i. They could be similar to the East African Rift valleys. The presence of streamlined islands and other geomorphic features indicate that the channels were most likely formed by catastrophic releases of water from aquifers or the melting of subsurface ice.
However, these features could also be formed by abundant volcanic lava flows coming from Tharsis. For example, the peak discharge required to carve the km-wide Ares Vallis is estimated to have been 14 million cubic metres million cu ft per second, over ten thousand times the average discharge of the Mississippi River.
Vertical exaggeration is extreme.
Note that residual ice cap is only the thin veneer shown in white on top of the plateau. Martian polar ice caps The polar ice caps are well-known telescopic features of Mars, first identified by Christiaan Huygens in The Environment Sector Research, Development and Evidence (R,D&E) framework was approved by MINMEC on 08 June This document addresses the need for a common framework for the collection of solid evidence that can be used in support of environment sector policy decisions and for the achievement of sector priorities.
PLoS ONE | Citations: , | PLoS ONE features reports of primary research from all disciplines within science and medicine. By not excluding papers on the basis of subject area, PLoS ONE. Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation.
As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig.
1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N 2 O) . Find out more about studying Geography BA Hons (L) at Lancaster University.
This module provides an introduction to environmental processes and their impacts in a variety of different environments. We discuss the physical processes governing the Earth's global climate system and their influence on recent and future patterns of climate and environmental change.
7. Dimension 3 DISCIPLINARY CORE IDEAS—EARTH AND SPACE SCIENCES. E arth and space sciences (ESS) investigate processes that operate on Earth and also address its place in the solar system and the galaxy. Thus ESS involve phenomena that range in scale from the unimaginably large to the invisibly small.