Search Results : geomorphos

Nov 162013
 

In an alliance with the Sonoran Institute, the National Geographic Center for Sustainable Destinations helped the region’s communities create the first transborder Geotourism MapGuide, covering northern Sonora and southern Arizona. The mapguide was published in 2007:

The maps  have vignettes of information about history, culture, geology and many other aspects of the region, making it a useful guide for geo-tourists. While some might argue about the choice of locations and attractions described on the maps, this is a useful addition to the background reading for anyone thinking of traveling to this region with some time on their hands to explore.

Surprisingly, the map has only a very brief and somewhat dismissive mention of the El Pinacate and Gran Desierto de  Altar Biosphere Reserve:

“Stand at the rim of this mile-wide volcanic crater and you may feel as if you’re on the moon. This land of ancient lava, sand, and cinder cones is sacred to the O’Odham people. Today, those on the Sonora side of the border call themselves “Pápago.”

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Geotourism in Mexico: García Caves (Grutas de García) in Nuevo León

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Oct 032013
 

The Garcia Caves (Grutas de García) are located in the Cumbres de Monterrey National Park, 9 km from the small town of Villa de García, and about 30 km from the city of Monterrey (state capital of Nuevo León). The highest point in the park is Copete de las Águilas which rises to 2260 m (7,410 ft) above sea level, but its best known peak is Saddle Hill (Cerro de la Silla), the distinctive saddle-shaped hill that overlooks the city.

Much of the park, including the mountains, are composed of sedimentary rocks that were originally laid down as marine sediments and then subsequently folded, uplifted and exposed to erosion. The extensive areas of limestone in the park, which date from the Cretaceous period, have been subject to karstification over 50 to 60 million years, which has resulted in typical karst landforms such as sinkholes, caves, cave formations and underground streams.

The Garcia Caves, one of the largest cave systems in Mexico, are deep inside the imposing Cerro del Fraile, a mountain whose summit rises to an elevation of 1080 meters above sea level, more than 700 meters above the main access road. The entrance to the caves is usually accessed via a short ride on a 625-meter cable car that was built to replace a funicular railway.

The cave system was first reported in 1843 by the Marmolejo family who informed their local prist Juan Antonio Sobrevilla that they had stumbled across it while looking for firewood.

Grutas de García. Credit: María de Lourdes Alonso

Grutas de García. Credit: María de Lourdes Alonso

Guided tours of the cave system show visitors some of its 27 separate chambers along a 2.5-kilometer (1.6 mile) route. The full system extends more than a kilometer further into the mountain reaching depths of more than 100 meters (340 feet) beneath the surface. The limestone of the cave walls contains lots of marine fossils. The caves have extensive and impressive formations of dripstone, including stalactities, stalagmites and other forms.

Unlike the suffocating heat of the Naica Crystal Caves in Chihuahua, the cave temperature here remains about 18̊C (65̊F) all year.

The chambers and formations have been given whimsical and imaginative names such as

  • “El salón de la luz” (The Light Chamber) where the natural translucence of the ceiling rock allows light from the outside to filter through.
  • “La octava maravilla” (The Eighth Wonder), a natural column formed where a stalagmite growing from the floor joined a stalactite, growing from the ceiling
  • “El mirador de la mano”, a stalagmite shaped like a human hand.
  • “El Nacimiento” (The Nativity),
  • “La Fuente Congelada” (The Frozen Fountain),
  • “La Torre China” (The Chinese Tower),
  • “El teatro” (The Theatre), and
  • “El Árbol de Navidad” (The Christmas Tree).

Want to read more about caves in Mexico?

Visit John Pint’s website for a selection of his writing, with many original articles, illustrated with great photographs, about many individual caves in Mexico.

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Watch La Primavera’s geological history unfold via a short video animation

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Jun 292013
 

Only days after we published our third post about the Primavera Forest, near Guadalajara, we were alerted to an excellent 9 minute video animation of how the area was formed. This short video about “The Exciting Geology of Bosque La Primavera” was produced by geologist Barbara Dye during her stint as a Peace Corps volunteer in Mexico.

The video can also be viewed in Spanish:

Dye has also written a beautifully-illustrated 72-page guide (in Spanish) to the geology of the Primavera Forest, entitled “La Apasionante Geología del Área de Protección de Flora y Fauna La Primavera.

Previous posts about La Primavera:

What are the 10 main pressures threatening the Primavera Forest in Jalisco?

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Jun 222013
 

A 1988 Management plan for the Primavera Forest (Plan de Manejo Bosque La Primavera), published by the University of Guadalajara, included a detailed list of the then-existing pressures on the forest.

Sadly, not much has changed since then, and almost all the sources of pressure mentioned in that study still apply today.

The Primavera Forest. Credit: Semarnat, 2003

The Primavera Forest. Credit: Semarnat, 2003

The management plan argues that the key areas (see map) where careful management is essential include:

  • Cerro San Miguel and Cerro Las Planillas, the highest elevations in the area
  • The environs of the tourist spa of Río Caliente (this spa is now closed)
  • Mesa de Nejahuete, in the center of the volcanic caldera, and
  • Mesa del León, considered an important habitat, primarily for fauna

The plan identifies the following sources of concern (note that this list is in no particular order, and certainly not in order of highest pressure to lowest):

1. Tourism. Poorly planned recreation areas, such as autodromes and spas. Issues resulting from this source of concern include pollution, waste disposal, soil erosion, landscape degradation, habitat change, reduced fauna and, switching to a human focus, delinquency. Motorcycles and trail bikes are a particular problem because of the associated noise pollution, annoyance and risk to other visitors, habitat destruction, the displacement of fauna and often lead to accelerated soil erosion.

2. Ejidos. Any expansion of neighboring ejidos means more homes, deforestation and landscape alteration.

3. Quarrying. The quarrying of local rocks such as pumice or river deposits, as well as a number of abandoned quarries can result in habitat destruction, erosion, forest degradation, accelerated mass movements (landslides, rockfalls), posing a risk to infrastructure, access routes and the potential pollution of ground water.

4. Hunting. Hunters leave spent cartridges that can pollute the soil, as well as wounded and abandoned animals. Larger fauna have become progressively more scarce. In addition, the presence of individuals carrying firearms poses a security threat.

5. Cultivation and Overgrazing. Increased cultivation (primarily for sugar cane, corn and beans) has gradually nibbled away at the edges of the forest, with the clearance method of slash and burn being a particular problem since it greatly raises the risk of wildfires, soil degradation and deforestation. As the number of access routes increases, it is easier for local farmers to graze livestock in the forest, reducing the health of the  grassland, and leading to a relative abundance of unwanted plants and weeds, accelerated soil erosion and the possible contamination of water sources.

6. Deforestation. Deforestation is also a pressure on the forest, in which the cutting of woodland for fuel (including bonfires) and for firebreaks, leads to changes in habitat and soil use, with the secondary effects of increased erosion, reduced ground water recharge and varying degrees of secondary forest succession.

7. Geothermal Power. The potential development of some areas for geothermal power by the Federal Electricity Commission (CFE) has already involved the opening of access routes and would lead to noise contamination (with adverse effects on fauna) and possible pollution of ground water, air and soil, as well as deforested hillsides. The loss of vegetation cover would trigger accelerated erosion, and habitat destruction, further reducing water quality. Access routes attract other “users” such as those seeking to quarry local rocks or clear land for farming.

8. Settlements. Settlements and subdivisions have also encroached on the forest. Some are irregular/illegal settlements, but others are private homes and clubs. Regardless of economic level, these settlements result in a decrease in vegetation and the elimination of the soil’s litter layer, leading to soil compaction, lowered infiltration rates, and nutrient-depleted soils, as well as increased pollution and the gradual elimination of native fauna

9 Wildfires. Wildfires, such as that in 2012, destroy vegetation and cause a general degradation of the woodland. They can result in the accelerated degradation of soil, water and vegetation, leading to significant changes to soil structure, as well as increased runoff and reduced groundwater recharge.

10. Inadequate regulations. The problems faced by the Primavera Forest are compounded because the relevant local authorities have shown little interest in ensuring adequate regulations, supervision and enforcement.

Many of these ten major pressures are closely interrelated. Despite the good intentions back in 1988, it is clear now, with the benefit of hindsight, that the 1988 management plan did not achieve very much. Hopefully, in the not too distant future, and as the Primavera Forest gains international status as a possible Geo-Park, a more comprehensive and effective management plan can be devised and implemented.

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How was the Primavera Forest caldera in Jalisco formed?

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Jun 102013
 

In a previous post, we described the considerable geotourism potential of the Primavera Forest near Guadalajara:

In this post, we take a closer look at how this unusual area was formed.

Stages 1 and 2 (see diagram):

140,000 BP. The magma chamber beneath the surface began to fill with magma (molten rock underground) and grow in size.

By about 120,000 BP, several lava flows and domes had formed, made primarily of rhyolite, a silica-rich (“acid”) igneous rock. After each eruption, the magma level underground would subside for a period of time before pressure built up again towards the next eruption.

Formation of a caldera

Fig. 4 of Bullard (1962) “Volcanoes in history, in theory, in eruption”. Based on van Bemmelen (1929) and Williams (1941)

Stages 3 and 4

So much pressure had built up by about 95,000 BP that there was a huge explosion, sending 20 cubic kilometers (4.8 cubic miles) of rock and ashes high into the sky. The explosion covered 700 square kilometers (270 square miles) with volcanic materials, known today as the Tala tuff (tuff is the geological term for consolidated ash). This massive explosion caused the upper part of the magma chamber to collapse, leaving a caldera that was 11 kilometers (6.8 miles) wide. The Tala tuff includes large quantities of pumice, a light and porous volcanic rock formed when a gas-rich froth of glassy lava solidifies rapidly.

This caldera filled with water, creating a lake.

Stage 5

This stage began shortly afterwards when a series of ring domes were erupted around the edge of the caldera as the magma deep below the surface started to push upwards again, eventually forming small islands in the lake. These eruptions formed more pumice, blocks of which would break off and start to float across the lake as they gradually sank to the lake floor.

A further series of eruptions in about 75,000 BP led to a second series of ring domes. A combination of tectonic uplift and sedimentation had filled the lake in by about this time.

More volcanic domes have been created at approximately 30,000 year intervals since, in about 60,000 BP and about 30,000 BP; these domes were almost all on the southern and eastern margins of the caldera, and include the lava domes of El Colli and El Tajo on the outskirts of Guadalajara.

Many geologists appear quietly confident that lava and ash eruptions in La Primavera are a thing of the past. They consider that the Primavera Forest’s fumaroles, hot river and hot waterfall represent the last vestiges of vulcanism and are no cause for alarm. On the other hand, others, including Gail Mahood who has studied this area far more than most, warn that hazard monitoring is justified in the case of La Primavera given its proximity to a major city and bearing in mind that any future eruption would be likely to occur on the southern and/or eastern side of the caldera.

The La Primavera Forest is only one of several calderas in Mexico’s Volcanic Axis.

If you prefer a short 9 minute video animation of how the area was formed, try this excellent YouTube video: “The Exciting Geology of Bosque La Primavera“, produced by geologist Barbara Dye during her stint as a Peace Corps volunteer in Mexico.

References:

  • Mahood G. A. 1980. Geological evolution of a Pleistocene rhyolitic center – Sierra La Primavera, Jalisco, Mexico. Journal of Volcanology and Geothermal Research, 8: 199-230.
  • Mahood, G.A. 1981. A summary of the geology and petrology of the Sierra La Primavera, Jalisco, Mexico. Journal of Geophysical Research, Volume 86.
  • Dye, Barbara. 2013. “La Apasionante Geología del Área de Protección de Flora y Fauna La Primavera”.

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Popocatapetl Volcano and Colima Volcano continue to erupt

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Mar 302013
 

In our series of brief updates on topics featured in previous Geo-Mexico posts, we look this week at the continuing eruption of two major volcanoes: Popocatapetl Volcano (between Mexico City and Puebla) and Colima Volcano (on the Jalisco-Colima state border in western Mexico).

Popocatepetl, 30 July 2012

Popocatepetl, 30 July 2012

Since our previous post, about a year ago, entitled Alert level rises as Popocatepetl volcano starts to erupt, Popocatapetl Volcano (photo) has continued to be active, with up to 250 activity events a day. The alert level has been reduced slightly to Yellow Phase 2, the fourth highest level. This level indicates intermediate scale explosive activity and possible expulsion of lava, explosions of increasing intensity and wind-blown ash falling on nearby villages. The volcano is monitored daily, and updates from CENAPRED  (in Spanish and English) are issued every 24 hours.

The report issued on 27 March is typical of recent months. In the previous 24 hours, there were 83 low intensity events with emissions of gas, water vapor and ash. The two largest events sent material rising 1000 meters and 600 meters into the atmosphere respectively, before the wind blew the material north eastwards (away from Mexico City).

Colima Volcano

In January 2013, we reported how Colima Volcano erupts, destroying lava dome first created in 2007. The volcano has continued to erupt in the ten weeks since then. The experts monitoring the volcano have reported up to 200 eruptive events a day, with numerous minor emissions of lava. Local villagers have been asked to remain on alert, though the experts are not yet calling for any villages to be evacuated.

The image below (source: Nasa Earth Observatory) shows Colima Volcano in 2010, part way into its current eruptive phase which is expected to last several years. The image shows the evidence at that time of four different types of volcanic activity:

  • lava dome growth
  • explosive eruptions
  • flank collapse
  • lava flows.

(Note that the 2013 eruptions have significantly altered the top of the volcano since this image was taken).

Nasa Earth Observatory)

Colima Volcano in 2010 (Nasa Earth Observatory)

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The crater lake of Santa María del Oro yields evidence for climate change

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Feb 142013
 

A magnificent crater lake nestles in a centuries-old volcanic crater a short distance east of the town of Santa María del Oro in Nayarit.

The connecting road from Highway 15 first passes through the former mining town of Santa María del Oro and then rises slightly to offer a splendid view of the beautiful slate-blue lake (known locally as “La Laguna”), set in a ring of verdant hills. In recent years, the lake, a good example of a geomorphosite, has become important for tourism with accommodations ranging from RV spaces to a boutique hotel. It takes about an hour and a half to stroll round the track that encircles the crater lake. Other attractions include visiting an abandoned gold mine (which offers a glimpse into the area’s past), birding, mountain biking, swimming or hiring a rowboat or kayak to venture out onto the lake.

Crater Lake, Santa María del Oro. Credit: Tony Burton

Crater Lake, Santa María del Oro. Credit: Tony Burton

This usually quiet lake has proved to be a valuable source of information for geologists and climatologists investigating the history of climate change in this region of Mexico.

The researchers who published their findings in 2010 in the Bulletin of the Mexican Geological Society extracted a sediment core from the deepest part of the lake. The relatively small area of the drainage basin surrounding the lake and the relatively steep slopes of surrounding hills mean that the sediments entering the lake are rarely disturbed after they are deposited. Wind and wave action are limited. The depth of the lake (maximum 65.5 meters) also helps to ensure that sediments remain undisturbed for centuries. This gives perfect conditions for a reliable sediment core.

Santa María del Oro. Credit: Google Earth

Santa María del Oro. Credit: Google Earth

The team analyzed the titanium, calcium and magnetism levels of successive thin slices of the core. By comparing the core with historic records and previous tree ring analyses from the same general area, they were able to accurately date each slice. The titanium levels in each slice allowed the researchers to quantify how much runoff occurred in that year, a proxy indicator of precipitation.

The team identified 21 significant drought events over a period of 700 years. The six most marked droughts occurred in 1365–1384, 1526, 1655-1670, 1818, 1900 and 1930-2000. They found periodicities of 25, 39, 50, 70 and 117 years for drought events, meaning that droughts occurred at fairly regular intervals of about 20-25 years.

The researchers then looked at the possible correlation between periods of drought and two distinct climatological factors: a shift to the south in the position of the Inter Tropical Convergence Zone (ITCZ) in summer and the occurrence of El Niño Southern Oscillation (ENSO) events. When the ITCZ does not extend as far north as usual during Mexico’s summer rainy season, states such as Nayarit and Jalisco receive less than their normal amount of rainfall. During ENSO events, rainfall is also diminished in central and western Mexico.

Of the 21 droughts identified and studied, 7 proved to be statistically linked to ENSO events, 10 to ITCZ movements, and the remaining 4 events were closely linked to a combination of both.

As the study concludes, titanium analysis of sediments may allow for a more refined record of climate change in the period prior to reliable historic or instrumental records which might improve the understanding of how and why climate change occurred in past

Santa María del Oro is also worth visiting because it is only a short distance away from the edge of the canyon of the River Santiago and the El Cajón hydro-electric power project, one of three major HEP projects located along that river.

Source article:

Susana Sosa-Nájera, Socorro Lozano-Garcí, Priyadarsi D. Roy and Margarita Caballero. Registro de sequías históricas en el occidente de México con base en el análisis elemntal de sedimentos lacustres: El caso del lago de Santa María del Oro. Boletín de la Sociedad Geológica Mexicana, Vol 62, #3, 2010, p 437-451.

Santa María del Oro and surrounding areas are described in chapter 24 of the recently published 4th (Kindle/Kobo) edition of my Western Mexico: A Traveler’s Treasury (Sombrero Books, 2013).

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Colima Volcano erupts, destroying lava dome first created in 2007

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Jan 142013
 

Colima Volcano (aka the Volcán de Fuego) is one of the westernmost volcanoes in Mexico’s Volcanic Axis, which straddles the country from west to east. The Volcano’s summit is only 8 km (5 miles) from the inactive Nevado of Colima volcano, Mexico’s sixth-highest peak, which rises 4260 m (13,976 ft) above sea level. (Curiously, despite their names, the summits of both volcanoes are actually located in the state of Jalisco and not the state of Colima.)

The elevation of Colima Volcano is officially given as 3820 m (12,533 ft) above sea level. In the past 400 years, it has been the most active volcano in Mexico, having erupted at least 30 times since 1576.

It is also considered to be one of the country’s most dangerous volcanoes. Numerous villages in its shadow keep a wary eye on its level of activity, and emergency evacuations have become a regular event in the past fifty years.

Colima Volcano, 11 Jan 2013. Photo: Protección Civil.

Colima Volcano forms new crater, 11 Jan 2013. Photo: Edo de Jalisco Protección Civil.

On a geological time-scale, the volcano first erupted about five million years ago in the Pliocene period, long after activity ceased at the nearby, and higher, Nevado de Colima. It quickly developed into a large volcano which partially blew apart or collapsed during Pleistocene times to form a caldera, five kilometers across. A new cone developed inside the caldera. This is the Volcán de Fuego we see today.

The cone is built mainly of pyroclastic materials (ashes and volcanic bombs) of andesitic composition together with some basaltic lava, making it a classic example of a composite volcanic cone.

Historically, the eruptions of the volcano have fallen into a definite cyclical pattern with periods of activity, each lasting about 50 years, interspersed with periods of dormancy. The first cycle of activity (after the Spanish arrived in Mexico) was between 1576 and 1611. Major eruptions occurred in 1680 and 1690, and further complete cycles occurred between 1749 and 1818, and from 1869 to 1913. Most geologists agree that current activity is part of the fifth cycle, which began in 1961.

A three year sequence of prior activity (2003 to 2005) is shown on this series of NASA satellite images.

Hazard Map of Colima Volcano (2003) Credit: Universidad de Colima, Observatorio Vulcanológico

Hazard Map of Colima Volcano (2003) Credit: Universidad de Colima, Observatorio Vulcanológico. Click for full-size image (large file size)

In each major cycle, the first results of renewed activity force new lava into the existing crater, forming a dome. Once the crater has filled up, any additional lava is ejected from the crater and flows down the volcano’s flanks. If the lava is unable to escape (relieving the underground pressure), the dome is liable to explode, which is exactly what happened a few days ago:

As on several previous occasions, once the subterranean pressure that caused the activity has been relieved, activity should cease, and the volcano will enter another less dangerous dormant phase. Even during this phase, a plume of hot gas often billows out from the volcano.

The dome that was destroyed in January 2013 began to build in 2007. The explosive activity on 6 January and 10 January 2013 left behind a new crater 220 meters (720 ft) across and about 50 m (165 ft) deep. According to the Jalisco-Colima Scientific Committee (which oversees the hazard analysis posed by the volcano), the events of 6 and 10 January emitted an estimated  1.5 million cubic meters of material, which formerly formed the dome. The 10 January explosion, which occurred at 21:40 hrs local time, sent incandescent material down the west flank of the volcano. An ash column rose about 3000 meters into the air before traveling north-eastwards on the wind towards the city of Ciudad Guzmán.

Thermal imaging shortly after the 10 January explosion showed that the temperatures in the crater are below 200 degrees Centigrade, which indicates relatively little gaseous build up and limited risk of further major explosions. Even so, a prudent 7.5 km exclusion zone is being maintained around the volcano.

Update (29 Jan 2013):

Another explosion at 3:58 am on 29 January 2013 created a plume of ash and cinders that rose more than 3000 meters above the volcano. The ash fell of nearby villages, including Los Mazos, Ejido Atenquique, Tuxpan and Huescalapa.

The area around the volcanoes is described in more detail in chapter 15 of “Western Mexico, a Traveler’s Treasury” (4th edition; Sombrero Books, 2013).

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Oct 272012
 

Beautifully illustrated with 32 color plates, the 81-page book A Drink Named Tequila traces the history and mystery of tequila (the liquor) from its ancient roots to today. The text, by one of Jalisco’s foremost historians, José María Muria, provides many fascinating insights into Mexico’s national drink.

For example, did you know what the agave (maguey) plant, from which tequila is derived, represented in the ancient Nahuatl culture? “In the Nahuatl culture, the maguey was a divine creation that represented Mayáhuel, a goddess who had four hundred breasts to feed her four hundred children.”

For a long time, the production of liquor of any kind was completely prohibited in New Spain:

“With the intention of favoring the importation and sale of produce from the major Iberian peninsular landowners, the Spanish Crown had prohibited the production of liquor in America, and brutally persecuted those who disobeyed. This, as well as to ensure – at least, so they said – that the Indians and mestizos would consume less, was why mescal was born and raised clandestinely. In turn, this explains why it took so long to leave clear proof of its existence and why today we know so little of its teething stages and first, tottering steps.”

Many of the early tequila brands were given feminine names:

“It became common for distilleries to be baptized with a feminine variant of the surname of their owner; Martinez: “La Martineña”; Guarro: “La Guarreña; Gallardo: “La Gallardeña”; Flores: “La Floreña”; Quintanar: “La Quintaneña”, etcetera. It also became common to link the brand name with some positive quality, as in the case of … “La Perseverancia” (“The Perseverance”), or…  “La Constancia” (“The Certainty”).”

Of interest to historians looking at the migration of rural businessmen from the site of their wealth in the countryside toward the cities, Muria writes that,

“Of all the great rural businessmen, the tequila producers were the last to move their places of residence from the countryside. As the twentieth century began, it is well known that practically all the hacienda owners had relegated their ancestral residences to the role of summer homes or for occasional visits, given that now their greatest desire was to figure prominently in the loftiest circles of society in Mexico’s provincial capitals, the capital of the Republic, or even in Paris or some other flashy European city.”

The book does have a handful of minor flaws. For example, Muria writes that the cocktail known as a margarita is made from “a combination of tequila with a dash of lime juice, mint and salt”. Perhaps he wrote this phrase after tasting one too many tequilas, since for a genuine margarita, his “mint” would need to be replaced by a shot of orange-flavored liqueur such as cointreau or Gran Marnier.

Despite such minor details, A Drink Named Tequila (Editorial Agara, 1996) remains a fascinating and well-illustrated read.

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Sep 012012
 

Tequila is made by distilling the juice of certain species of agave plants. Agaves are commonly called “century plants” in the USA, a name derived from the length of time they supposedly grow before producing a flowering stalk – actually, from eight to twenty years depending on the species, rather than the hundred suggested by their common name! Some species flower only once and die shortly afterwards, others can flower almost every year. Agaves are no relation botanically to cacti, even though they are often mistakenly associated with them. The ideal agave for tequila is the Agave tequilana Weber azul which has bluish-colored leaves.

Agave field in Jalisco

Agave field in Jalisco. Photo: Tony Burton

The tequila agaves are started from seed or from onion-size cuttings. When the plants are mature (about 10 years later), their branches are cut off, using a long-handled knife called a coa, leaving the cabeza (or “pineapple”), which is the part used for juice extraction. Cabezas (which weigh from 10 to 120 kilos) are cut in half, and then baked in stone furnaces or stainless steel autoclaves for one to three days to convert their starches into sugars.

From the ovens, the now golden-brown cabezas are shredded and placed in mills which extract the juices or mosto. The mixture is allowed to ferment for several days, then two distillations are performed to extract the almost colorless white or silver tequila. The spirit’s taste depends principally on the length of fermentation. Amber (reposado) tequila results from storage in ex-brandy or wine casks made of white oak for at least two months, while golden, aged (añejo) tequila is stored in casks for at least a year, and extra-aged (extra añejo) for at least three years.

Distillation: the Filipino Connection

Mexico’s indigenous Indians knew how to produce several different drinks from agave plants, but their techniques did not include distillation, and hence, strictly speaking, they did not produce tequila. Fermented agave juice or pulque may be the oldest alcoholic drink on the continent; it is referred to in an archival Olmec text which claims that it serves as a “delight for the gods and priests”. Pulque was fermented, but not distilled.

If the indigenous peoples didn’t have distilled agave drinks, then how, when and where did distillation of agave first occur? In 1897, Carl Lumholtz, the famous Norwegian ethnologist, who spent several years living with remote Indian tribes in Mexico, found that the Huichol Indians in eastern Nayarit distilled agave juice using simple stills, but with pots which seemed to be quite unlike anything Spanish or pre-Columbian in origin.

By 1944, Henry Bruman, a University of California geographer, had documented how Filipino seamen on the Manila Galleon had brought similar stills to western Mexico, for making coconut brandy, during the late sixteenth century.

Dr. Nyle Walton, of the University of Florida, expanded on Bruman’s work, showing how the Spanish authorities had sought to suppress Mexican liquor production because it threatened to compete with Spanish brandy. This suppression led to the establishment of illicit distilling in many remote areas including parts of Colima and Jalisco. Even today, the word “tuba”, which means “coconut wine” in the Filipino Tagalog language, is used in Jalisco for mezcal wine before it is distilled for tequila. This is probably because the first stills used for mezcal distillation were Filipino in origin.

“Appelacion Controlée”

Though colonial authorities tried to suppress illegal liquors, the industry of illicit distilling clearly thrived. One eighteenth century source lists more than 81 different mixtures, including some truly fearsome-sounding concoctions such as “cock’s eye”, “rabbit’s blood”, “bone-breaker” and “excommunication”! By the 1670s, the authorities saw the wisdom of taxing, rather than prohibiting, liquor production.

For centuries, distilled agave juice was known as mezcal or vino de mezcal “mezcal wine”). It is believed that the first foreigner to sample it was a Spanish medic, Gerónimo Hernández, in the year 1651. The original method for producing mezcal used clay ovens and pots.

By the end of the nineteenth century, as the railroads expanded, the reputation of Tequila spread further afield; this is when the vino de mezcal produced in Tequila became so popular that people began calling it simply “tequila”. When the Mexican Revolution began in 1910, it swept away a preference for everything European and brought nationally-made tequila to the fore. Tequila quickly became Mexico’s national drink. It gained prominence north of the border during the second world war, when the USA could no longer enjoy a guaranteed supply of European liquors.

To qualify as genuine tequila, the drink has to be made in the state of Jalisco or in certain specific areas of the states of Nayarit, Guanajuato, Michoacán and Tamaulipas. (We will take a closer look at this distribution in a future post).

The ideal growing conditions are found in semiarid areas where temperatures average about 20 degrees Centigrade, with little variation, and where rainfall averages 1000 mm/yr. In Jalisco, this means that areas at an elevation of about 1,500 meters above sea level are favored. Agaves prefer well-drained soils such as the permeable loams derived from the iron-rich volcanic rocks in Mexico’s Volcanic Axis.

Production of tequila has tripled within the last 15 years to about 250 million liters a year (2010). About 65% of this quantity is exported. Almost 80% of exports are to the USA, with most of the remainder destined for Canada and Europe.

Connoisseurs argue long and loud as to which is the better product, but all agree that the best of the best is made from 100% Agave tequilana Weber azul. I’m no connoisseur, but my personal favorite is Tequila Herradura, manufactured in Amatitán, a town between Tequila and Guadalajara. Anyone interested in the history of tequila will enjoy a visit to Herradura’s old hacienda “San José del Refugio” in Amatitán, where tequila has been made for well over a century. The factory is a working museum with mule-operated mills, and primitive distillation ovens, fueled by the bagasse of the maguey. The Great House is classic in style, with a wide entrance stairway and a first floor balustrade the full width of the building.

Visitors to the town of Tequila, with its National Tequila Museum, can  enter any one of several tequila factories to watch the processing and taste a sample. They can also admire one of the few public monuments to liquor anywhere in the world – a fountain which has water emerging from a stone bottle supported in an agave plant. “Tequila tourism” is growing in popularity. Special trains, such as “The Tequila Express” run on weekends from the nearby city of Guadalajara to Amatitán, and regular bus tours visit the growing areas and tequila distilleries. The town of Tequila holds an annual Tequila Fair during the first half of December to celebrate its famous beverage. Another good time to visit is on 24 July, National Tequila Day in the USA.

In 2006, UNESCO awarded World Heritage status to the agave landscape and old tequila-making facilities in Amatitán, Arenal and Tequila (Jalisco).

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