exam 2

fjords

Fjords are long, narrow, deep inlets of the sea between high cliffs, typically formed by submergence of a glaciated valley. Most associated with Norway and Iceland, but the two on this slide, Doubtful Sound (at right) and Milford Sound (below), are found in New Zealand, where the spelling is fiord.

stable sand regions

Aeolian processes predominate in stable sand regions, particularly in arid desert regions. White Sands; Ernabella Longitudinal Dunes; Takli MakanDesert; Atacama Desert; Great Victorian Desert; Grand Erg Oriental

snowlines relative to elevation

in equatorial mountains, the snowline is around 5000 m; on midlatitude mountains, such as the European Alps, snowlines average 2700 m; and in southern Greenland snowlines are down to 600 m

Seif dunes

(means sword in Arabic) a sharp-crested sand dune with curved edges, often several miles long. Runs in a series of parallel ridges; most common in the Sahara Desert.

percentage of earth covered by glaciers

11, 30 during colder periods

What is an erg desert?

A common assumption is that most deserts are covered by sand. Instead, desert pavements predominate across most sub-tropical arid landscapes; only about 10% of desert areas are covered with sand. Sand grains generally are deposited as transient ridges or hills called dunes. A dune is a wind-sculpted accumulation of sand (See next slide). An extensive area of dunes, such as that found in North Africa, is characteristic of an erg desert, which means sand sea. Strictly speaking, the Sahara is an erg as defined by the Army Corps of Engineers. They classify an erg as a desert area containing more than 125 square kilometers (48 sq mi) of wind-blown sand, and where sand covers approximately 20% or more of the surface The Sahara:1.8 million square kilometers (20% of the Sahara's nine million kilometers)

dead sea

A landlocked salt lake The Dead Sea is so salty that only bacteria can live in the water 1,349 feet below sea level - lowest place on the exposed crust of the earth

Yardang

A small wind-sculpted rock formation caused by abrasion in Utah

calving

Calving is the breaking off of chunks of ice at the edge of a glacier.

loess continued

Loess deposits form some complex weathered badlands and some good agricultural land. In Europe and North America, loess is thought to be derived mainly from glacial and periglacial sources. The vast deposits of loess in China, covering more than 300,000 km2, are thought to be derived from desert rather than glacial sources.

permafrost regions categories

Permafrost regions are divided into two general categories, continuous and discontinuous, that merge along a general transition zone. Continuous permafrost describes the region of the most severe cold and is perennial, roughly poleward of the -7°C mean annual temperature. Continuous permafrost affects all surfaces except those beneath deep lakes or rivers. Continuous permafrost may exceed 1000 m in depth averaging approximately 400 m.

The epoch featuring most recent episode of cold climatic conditions, covering 30%of Earth's land area

Pleistocene

What are loess materials and how are they generated? What form do they assume when deposited?

Pleistocene glaciers advanced and retreated in many parts of the world, leaving behind large glacial outwash deposits of fine-grained clays and silts (<0.06 mm). These materials were blown great distances by the wind and redeposited in unstratified, homogeneous deposits named loess.

jordan river

Provides water to the region Flows from the mountains in Lebanon into the Dead Sea Natural boundary between Israel and Jordan

glaciers in chile

Rock glaciers in the Chilean Andes help supply the water for much of Chile, including the capital of Santiago

red sea

Separates the Arabian Peninsula and the continent of Africa Covers a rift valley created by the movement of the Arabian plate

moraine and moraine types defintions

Terminal moraines are found at the terminus or the furthest (end) point reached by a glacier. Lateral moraines are found deposited along the sides of the glacier. Medial moraines are found at the junction between two glaciers.

rub al khali

The Arabian Peninsula consists of the Rub-al-Khali, which is the most famous desert in the region, thus that area also has a desert climate. Dromedary camel fennec, or desert fox dromedary camel lepgecko death stalker scorpion leopard gecko

The Elburz Mountains

The Elburz Mountains cut off easy access to the Caspian Sea for Iran

hindu kush mountains

The Hindu Kush Mountains of Afghanistan are linked with other mountain ranges that frame South Asia

atlas mountains

The Orographic effect occurs when an air mass approaches a mountain range and is rapidly forced upward. This cause moisture in the air mass to cool and create precipitation, which then falls on the windward slope The opposite side [the leeward slope] receives little if any precipitation, creating what is known as a rainshadow. morroco algeria tunisia

The Taurus Mountains

The Taurus Mountains separate Turkey from the rest of the Middle East

The Zagros Mountains

The Zagros Mountains on the western side of Iran isolate the country from the rest of the Middle East

Describe the active zone in permafrost regions, and relate the degree of development to specific latitudes.

The active layer is the zone of seasonally frozen ground that exists between the subsurface permafrost layer and the ground surface. The active layer is subjected to consistent daily and seasonal freeze‑thaw cycles. This cyclic melting of the active layer affects as little as 10 cm depth in the north and up to two meters in the southern margins of the periglacial region, and 15 m in the alpine permafrosts.

sahara

The largest hot desert in the world Sahara means "desert" in Arabic Temperatures can rise as high as 136.4 degrees F in the summer Temperatures can also fall below freezing at night in the winter The Sahara is made up of sand dunes, mountains, rock formations, and gravelly plains Travel in the Sahara is risky because of the extreme conditions. Many travelers rely on camels because camels can go for up to 17 days without water. Also, wind-blown sand has little effect on a camel because it closes its nostrils and just keeps walking. As much as 6,000 feet under the Sahara are huge stores of underground water called aquifers. In some areas, this water has come to the surface, which is called an oasis. It supports vegetation and wildlife and is critical for people living in the desert.

The Role of Albedo?

The term albedo is applied to the reflectivity or reflecting power of a surface. It is the ratio of reflected radiation from the surface to incident radiation upon it. Lighter surfaces: Higher albedo=cooler Darker surfaces: Lower albedo-warmer The ice-albedo feedback loop [visualization on the next slide]: Intact ice is lighter, meaning it is reflecting incoming radiation and in cooler. Melting ice loses this luster and begins to take on the appearance of the surrounding landscape, turning darker and more prone to absorbing incoming radiation, becoming warmer. This makes it even darker, triggering even more melting.

Name the three types of continental glaciers. What is the basis for dividing continental glaciers into types? Which type covers Antarctica?

The three types are ice sheet, ice cap, and ice field. Both ice caps and ice sheets completely bury the underlying landscape, although an ice cap is somewhat circular and covers an area of less than 50,000 km2. An ice field is the smallest of the three.

tigris and euphrates

Two of the most important rivers in the Middle East Supported several ancient river valley civilizations in a larger area known as the Fertile Crescent Flow through parts of Turkey, Syria, and Iraq The valleys are fertile, well watered, and great for agriculture Flow almost parallel to each other for hundreds of miles Join at the Shatt al Arab and then flow into the Persian Gulf

Define two types of permafrost, and differentiate their occurrence on Earth. What are the characteristics of each?

When soil or rock temperatures remain below 0°C (32°F) for at least two years, a condition of permafrost develops. An area that has permafrost but is not covered by glaciers is considered periglacial. Note that this criterion is based solely on temperature and not on whether water is present. Other than high latitude and low temperatures, two other factors contribute to permafrost: the presence of fossil permafrost from previous ice-age conditions and the insulating effect of snow cover or vegetation that inhibits heat loss.

Differentiate between two forms of glacial drift—till and outwash.

Where the glacier melts, debris accumulates to mark the former margins of the glacier—the end and sides. Glacial drift is the general term for all glacial deposits. Direct deposits appear unstratified and unsorted and are called till. In contrast, sorted and stratified glacial drift, characteristic of stream-deposited material, is called outwash and forms an outwash plain of glaciofluvial deposits across the landscape.

fluid threshold

Wind exerts a drag or frictional pull on surface particles. Bagnold studied the relationship between wind velocity and grain size, determining the fluid threshold (minimum wind speed) required for initial movement of grains of various sizes. A slightly lower wind velocity suffices if the particle already has been set into motion by the impact of a saltating grain. Ralph Bagnold termed this lesser velocity the impact threshold. Once in motion, particles continue to be transported by lower wind velocities.

Transverse dunes

are asymmetrical ridges which are transverse (perpendicular) to the wind direction. Surface has abundant sand supply

Barchan dunes

are crescent shaped dunes with horns pointed downwind. Winds are constant with little directional variability. Limited sand availability.

Parabolic dunes

are generated by vegetation, open end faces upwind with U-shaped and arms shaped by the vegetation.

Longitudinal dunes

are long, ridge-shaped dunes that are aligned parallel to the wind direction and have two slipface. Average 100 meters high and 100 kilometers long and can reach to 400 meters high.

Barchanoid ridge dunes

are wavy, symmetrical dune ridges aligned in right angles to the winds. Formed from coalesced barchans.

blockfield

s a surface covered by boulder- or block-sized angular rocks usually associated with alpine and subpolar climates and periglaciation