GEOGRAPHY 3333
GEOGRAPHY OF LATIN AMERICA
PHYSICAL GEOGRAPHY

Discussing lands covering an area of 1 and 1/2 continents
*Wide range of natural environments
    Antarctic to equatorial rainforest
How peoples have viewed the Latin American environment

    1.    Indian civilizations - environment as a god
    2.    Spanish/Portuguese - environment as prey, plunder
    3.    Environment as an illusion - "paradise found"
                17th/18th century European explorers
    4.    Environment as an obstacle - both Indian and colonists
                Environment as a challenge


Landforms - Active Tectonic Setting
*Pacific slope - Pacific Ring of Fire
        Converging plate boundary
        Pacific and sub-plates (Cocos, Nazca) colliding with North/South American plates
                Subduction zone
                        Benioff (shallow, intermediate, and deep) earthquake zone
                        Pyroclastic (explosive) volcanic activity
                                Huascaran (Peru), Nevado del Ruiz (Colombia), Fuego and Acatenango (Guatemala),

 

Volcan de Fuego, near Antigua, Guatemala

Pyroclastic eruption, Volcan de Fuego, August, 2002

 

June, 1974 eruption of Volcan de Pacaya, Guatemala


                                Nevado de Colima (Mexico) and many others
        Eastern Caribbean (Lesser Antilles) - subduction zone
                Mt. Pelee (Martinique, 1902, destroyed St. Pierre), Montserrat (Soufriere Hills - currently active)
Atlantic coast (Brazil) - passive continental margin
        Similar to Atlantic coast of the United States - no volcanic activity, low hills, remnants of old mountains
Mexico - major mountain ranges
        Sierra Madre Occidental - Cenozoic (recent), volcanic, wide, cut my deep canyons (Barranca del Cobre)
        Sierra Madre Oriental - Laramide orogeny, contemporary with Rockies, steep, narrow

Front Range, Sierra Madre Oriental, near
El Encino, Tamps., Mexico

 

 

Front range, Sierra Madre Oriental, as seen from Gomez Farias, Tamps., Aug. 5, 2006


        Sierra Madre del Sur - Oaxaca, Guerrero
Volcanic chains
        Central Mexico Volcanic axis - cuts across Mexico from Nayarit to Verazcruz (Catemaco caldera)
        Central American volcanic axis - Tacana (Mex-Guate border) to Costa Rica
                Rivals Japan - 40 active volcanoes, parallel Pacific coast
        Andes Mtns. - Venezuela/Colombia to Argentina/Chile - world's longest continental mountain range
                Volcanoes 6500 m in elevation - some are covered with snow and ice caps
                        Landslides, mudslides - Nevado del Ruiz (Colombia), 20,000 fatalities
Earthquakes - frequent along Pacific
        Deep ocean trench - Mexico City earthquake, 1985 - epicenter in Acapulco Trench, 8.3 magnitude
        Earthquakes of 7.0-8.0 common along Pacific slopes
        Eric Wolf - writes anthropology book on Mexico and Guatemala - title - Sons of the Shaking Earth



Interior valleys are significant
Mexico
        Mesa del Norte
        Mesa Central
                Valley of Mexico
        Oaxaca
Peru, Bolivia
        Altiplano - high, dry valleys between ranges of the high Andes


Lowlands

Middle America - not extensive
        Pacific Coast plain
                Narrow, fertile
                In places of volcanic origin
                        Pacific coast of Guatemala
        Gulf Coast plain
                Veracruz - volcanic - fertile
                Yucatan - limestone, rocky, thin soil
                        Infertile
South America - lowlands are more extensive
        Amazon Basin
        Gran Chaco
       *Pampas - Argentina, mollisols - very rich soils
                   Grasslands
        Patagonia



Be able to label the following on a landform map of South America
        Humboldt Current
        Atacama Desert
        The Dry Northeast (caatinga)
        Andes Mtns.
        Guiana Highlands
        Brazilian Highlands
        Rio Amazonas
        Rio Orinoco
        Rio Parana
        Gran Chaco
        Mato Grosso
        Las Pampas
        Patagonia
        Llanos
        altiplano



The extensive mountain systems in Latin America result in ecological diversity!

        Veracruz to Mexico City - 400 km, equal to travel from Florida Keys to Labrador - 3000 km!
                Encounter same amount of environmental change!


Climates

Oversimplified climate classification

A - tropical
        Coldestmonth above 18
C - example - Veracruz, Manaus
B - dry climate - northern Mexico (Monterrey)
C - mild climate - coldest month between 0o C and 18o C
D - continental climate - 4 distinct seasons, cold, snowy winter, warm to hot summer
E - polar/highland climate - cool summer, permanent snow and ice fields

        All but D present in Latin America
 



*In the tropics the major control on climate is altitude

Temperature drop with altitude
        6.4o C./1000 m
        Veracruz - 35o C.(95o F) , DF - 21o C (70o F)
Tierra Caliente - 0 to 900 m
        Hot lands - tropics
        Hot, humid
        Coastal lowlands of Caribbean and Atlantic, Pacific coast of Colombia
        Veracruz, Cartagena, Santo Domingo
        Sugar cane, coconuts, bananas, tropical fruit


Tierra Templada - 900 - 1800 m
        Mild country
        Japala, Caracas, San Jose (Costa Rica)
        When wind facing slopes can receive intense moisture
        Cafe (coffee) zone, maize, bananas, avacados


Tierra Fria - 1800 to 3600 m
        Cold country
        Mexico, D.F., Bogota, Cuzco
        Ave. daytime temp. - 20o C (about 70o F), much cooler at night
        Wheat, potatoes, pasture


Tierra helada - above 3600 m
        Frequent frosts
        Pasture, some potatoes
        La Paz, Bolivia

Altiplano - Image courtesy of Consuelo Molina, San Fernando, CA

Climate and Seasons

Most (but not all) of Latin America is in the tropics 
        Some of it is "above" the tropics
Altitude - major control on climate
Second control is season
*INTERTROPICAL CONVERGENCE ZONE (ITCZ)!


        Low pressure trough located a few degrees n. or s. of the equator
          Zone of instability
          Moves n. & s. with the high sun
          Initiates rainy season
Rainy season - May-Oct (greater in the south) (Mexico)

Tropical Atlantic Satellite Image, August 28, 2006

Tropical Storm Ernesto, August 28, 2006

Mexico Satellite, showing ITC, Hurricane John, and Tropical
Storm Ernesto, August 30, 2006

 

 


Dry season - Nov-May (longer in the north)  (Mexico)
Third control are the mountains -
           Both Sierra Madre Occidental and Oriental block moisture from reaching the interior
           Mesa Central and especially Mesa del Norte are rainshadows/deserts

 

High desert near Bavispe, Sonora
 

Peru/Humboldt Current - cold water upwelling along Pacific Coast of Peru/n. Chile
Cool, foggy, conditions! Dichotomy - Atacama - World's Driest Desert!
Settling air - inhibits precipitation

World Ocean Currents

Sea Surface Temperatures, October 19, 2004


El Niño - equatorial countercurrent - every 5-7 years, warm water to Pacific Coast
of South America - Stormy weather!


 

Observations

 

Soils - Pacific lowlands - volcanic, rich
            Gulf lowlands (except Ver.) - soils are leached, infertile
            Yucatan - rocky, limestone - thin soils
Highland soils - volcanic, fertile

Volcanic soil profile, Volcan de Fuego, Guatemala


Highlands - settlement has been continuous for 3,000 yrs.
            Good soils
            Problems
                    Erosion
                    Lack of rainfall
                    Frosts
Lowlands - discontinuous occupations
            Poor soils
            High temp., rainfall
            Have seen development of civilization, then abandonment