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Popular Issue, VI (III), July, 2013, p. 1-27
Geological history of the Baja California
Peninsula, Mexico and the fascinating world of its
endemic plants
Arun Kumar
The peninsula of Baja California is located in the northwestern
part of Mexico; it covers an area of 71,777.589 km2…. The
oldest known rocks in Baja California are metamorphosed
remnants of Lower Paleozoic. The present form of Baja
California developed during the last 5-10 million years as the
continent opened forming the Gulf of California about 5 million
years ago. Due to long isolation during its geological past,
topographic heterogeneity (Figures 31- 40), and diverse weather
regimes it has high levels of endemism and diversity.
As a graduate student working for my Ph.D. degree in the Department of Geological
Science at Michigan State University (MSU), USA I got a unique chance to visit the peninsula of
Baja California, Mexico(Figures 1 and 2) during the summer months of 1974. This was a forty
five day long geological and botanical trip led by Prof. Aureal T. Cross. The group comprised of
five students: Enrique Martinez-Hernandez, Gordon D. Wood, Christopher Cross, Sue (I have
forgotten her last name) and I. Enrique was from Mexico and I from India; the rest of them were
Americans. Prof. Cross and his students had been working for the past decade on the geology
and plant ecology of the Baja Peninsula as well as on the environmental and geological controls
over the distribution of palynomorphs in the Gulf of California (Figures 1, 2 and 8). Our trip was
part of the same ongoing research project in which we collected a lot of sediment and soil
samples from various sedimentary environments primarily from the northern part of the
peninsula. We observed various geological features of this peninsula but the main highlight of
the trip was an opportunity to observe a unique assemblage of endemic plants of Baja California.
In addition to the great learning experience it was a once in a life time occasion to see a remote
part of the world and meet its people and experience their culture. I absolutely enjoyed this
memorable trip.
We packed our field van (Figures 6 and 9) with various kinds of canned food, water, soft
drinks, fruit juices and every imaginable equipment that we needed for our field work along with
our personal belongings. We left the MSU campus in East Lansing, the eastern suburb of
Lansing the capital city of Michigan, and drove across the United States to Los Angeles in
California on the west coast. We spent a few days in and around the Los Angeles area studying
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its regional geology and spent one day at the Rancho La Brea Tar Pit within the confines of the
city. La Brea Tar Pit is famous for providing a large collection of Pleistocene-Holocene
vertebrate and plant fossils. I plan to write a separate article on La Brea Tar Pits. We drove south
to San Diego on our way to the US-Mexico international border and reached Tijuana (Figure 2) a
Mexican town just south of the border.
From Tijuana we drove east to Mexicali and south to San Filipe (Figure 2). Between
Mexicali and San Felipe we passed through the delta region of the Colorado River. This was a
major wetland in the past but has now become a desert (Figure 3) because a large number of
dams have been constructed within the American territory and hardly any water is allowed to
flow into the delta region. All the water of this great river is used up in the USA. From San
Felipe we drove northwest to Ensenada on the Pacific coast; a town south of Tijuana. From
Ensenada we drove south on the Baja California Highway to the port town of Santa Rosalia
(Figure 8 and 9) within the state of Baja California Sur. On the way we witnessed a gigantic steel
monument (Figure 7) marking the construction of the Baja California Highway that ran through
the length of this long peninsula.
We boarded a ship at the Santa Rosalia port (Figure 8) and after an overnight journey we
crossed the Gulf of California and next morning we reached the port city Guaymas (Figure 9) in
the state of Sonora on mainland Mexico. From Guaymas we drove north to Hermosillo and on to
Santa Ana. From here we drove northwest to Mexicali in Baja California. On the way in the state
of Sonora we saw a rail-cum road bridge (Figure 11). In Mexicali we crossed over to the
American state of California. After doing some more geological work in the Imperial Valley
deserts of southern California we drove back to MSU. During this trip we did geological work,
collected a large number of sediment and soil samples and camped (Figure 6) in the deserts of
Baja California and mainland Mexico.
The Baja California Peninsula and the Gulf of California
The peninsula of Baja California is located in the northwestern part of Mexico; it covers
an area of 71,777.589 km2. This peninsula extends to almost 1,300 km from north to south and is
a land of steep mountain ranges and coastal valleys. Tijuana and Mexicali are cities just south of
the US border, and Mexicali is the capital city of Baja California. It is situated 193 km west of
Tijuana. San Lucas is the southernmost town of this peninsula that lies south of the Tropic of
Cancer. The Gulf of California (or as the Mexicans call it the Sea of Cortez) separates this
peninsula with mainland Mexico and the maximum distance between the two is 250 km. The
Pacific Ocean lies on the west of Baja California. Several NNW to SSE trending mountain
ranges are present on this peninsula, and El Monte Picacho del Diablo is the highest peak that
rises to 3,095 m above the mean sea-level. Desert areas comprise about 65% of the peninsula.
The largest desert in Baja California is the Vizcaíno Desert, located in the west-central part, that
has been designated a protected Biosphere Reserve by the United Nations. This peninsula has a
variety of types of geological environments like coastal wetlands, sandy beaches, over 100
islands mostly located along the Gulf coast and deep gorges filled with a variety of palm trees.
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The climate of the Baja Peninsula ranges from Mediterranean to tropical and 69 % of the
region is hot deserts with little rainfall in winter with hot and dry summers when temperatures
may rise up to 52° C. Generally the mountains are cooler with occasional snowfall in higher
regions of the northern areas. The Pacific coast is cooler than the Gulf coast during summer but
can be warmer than the Gulf coast during the winter; likewise the northern part of the peninsula
is cooler than the southern part. There are a few climatic modifications, based on the interplay of
mountains, bays, ocean currents, fog and winds, etc. During summer and fall tropical storms
locally known as chubascos may bring rain and winds that may last for a few hours to a few
days. Hurricanes are infrequent, yet occasionally occur from time to time, for e.g. Hurricane
John in 2006 severely impacted Cabo Pulmo causing heavy rains and 240 km/hour winds all the
way to Mulegé and Santa Rosalía.
There are approximately 2,958 plant species, of which 686 are endemic. A large number
of mammals, reptiles and bird species too are endemic. Pacific coast is home of wolves, elephant
seals and gray whales. There are innumerable species of fish and sea birds along the coastal
regions. Pine and oak grow on mountain ranges but the landscape consists mainly of cacti.
Figure 1: Satellite view of Baja California peninsula of Mexico. (Website 1)
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The Gulf of California is also known as Sea of Cortez in Mexico and was named after
the16th century Spanish explorer Hernán Cortés. The Mexican government changed the official
name to the Golfo de California (Gulf of California) in the early 20th century, although both
names are in vogue and are interchangeably used on maps. This gulf is over 1000 km long that
extends from the mouth of the Colorado River in the north to the cape at San Lucas in the south
(Figure 2). The Colorado River Delta was once the most important wetland of the Western North
America now has become almost like a desert due to this river being dammed within the USA.
The sea is shallow in the north because sediment brought by the Colorado River forms a huge
delta that extends from land into the sea. This gulf south of La Paz becomes more or less like an
ocean, with deep trenches, canyons, and tall seamounts, and meets the Pacific Ocean further
south at the southernmost tip of the Baja Peninsula known as Finisterra or the Land’s End. A
geographical summary of the Baja Peninsula is given in the website 6.
Figure 2: Map of Baja California and northwestern Mexico showing towns and roads (Website
2)
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Figure 3: The delta of Colorado River once a fertile region now looks more like a desert because
the river’s water is dammed and used in the USA. (Photo: The author, June, 1974)
Figure 4: A small roadside town in the Baja California state in Mexico. (Photo: The author,
June, 1974)
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Figure 5: A small village in the Baja California state in Mexico. Notice the remarkable
similarity (except for the plants) with a village in the Bundelkhand region of Uttar Pradesh,
India. (Photo: The author, June, 1974)
Figure 6: Our van and the camp site. The early morning chores before we got ready for the long
field trip. We all did our designated jobs but Prof. Aureal T. Cross (left) used to prepare
breakfast for us. (Photo: The author, June, 1974)
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Figure 7: My friend Enrique Martinez-Hernandez (left) and I at the monument to celebrate the
completion of Baja California Highway in 1973. (Dr. Martinez-Hernandez is now a professor at
Instituto de Geologia, Universidad Nacional Autonoma de Mexico (UNAM) in Mexico City.
(Photo: Gordon D. Wood, June, 1974)
Figure 8: The ship in which we traveled across the Gulf of California (Sea of Cortez) from Santa
Rosalia in Baja California Sur to the port of Guaymas in the northwestern Mexican state of
Sonora. (Photo: The author, June, 1974)
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Figure: 9: After an overnight journey from Santa Rosalia in Baja California Sur to the port of
Guaymas in the northwestern Mexican state of Sonora, our van is coming out of the ship.
(Photo: The author, June, 1974)
Figure 10: The port of Guaymas in the northwestern Mexican state of Sonora. (Photo: The
author, June, 1974)
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Figure 11: A rail cum road bridge on the highway connecting Hermosillo (Sonora) to Mexicali
(Baja California) just south of the USA-Mexico border. (Photo: The author, June, 1974)
Geology of Baja California Peninsula
Johnson et al. (2003) edited a volume of several research papers on the tectonic evolution
of northwestern Mexico and southwestern USA. This volume contains significant papers on the
geology and geological history of the Baja California. Other useful references that provide basic
knowledge on the region’s geology and various geological maps are by Minch et al. (1998) and
Gastill et al. (1975).
Geology of the Baja California Peninsula is summarized by Minch et al. (2011: website
3), they state that geological landforms of this peninsula can be divided into 5 provinces. The
first three provinces result from the Cretaceous collision of the North American and the Pacific
Plate and the last two result from the opening of the Gulf of California. These provinces are as
follows:
1. The tilted granitic fault blocks are represented by the Sierra Juarez and the Sierra San
Pedro Martir forming the main granitic ranges of the of Baja California. The main rock
types are granitic, metamorphic, and metavolcanic.
2. The broad flat coastal plains are represented by the Vizcaino and Magdalena Plains in
southern Baja California with up to thirty thousand feet of sandstone, shale, and
conglomerate deposited in a basin in a broad belt in the subduction zone.
3. The isolated coastal mountains represent the scrapings from the sea floor of the Pacific
Plate and mantle rocks (serpentine) which have been deeply buried, metamorphosed and
brought back to the surface.
4. The fault-block mountains and alluvial valleys form the Basin Ranges of the Gulf of
California (Figures 12, 13, 17). Most of the block mountain ranges and alluvial valleys of
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Baja California belong to this province and are related to the opening of the Gulf of
California.
5. The Volcanic regions are represented by broad plateaus and mesas in southern Baja
California (Figures 14, 15, 16). They were formed as a result of volcanism associated
with the passing of the East Pacific Rise under the continent and beginning of opening of
the Gulf of California.
It is well known that Earth’s crust is composed of several large and small semi-rigid
plates that “float” on the mantle, and constantly move relative to each other. When two plates
pull apart from each other they form ridges or rises in oceanic crust and rifts, for example the
Gulf of California. When two plates push against each other, one plate goes down under the
other forming subduction zones and island arcs. When two plates slide against each other they
form lateral or strike-slip faults, for example the San Andreas Fault in California. All major
features on the earth's crust result from interaction of the plates, and this motion is extremely
slow.
The oldest known rocks in Baja California are metamorphosed remnants of Lower
Paleozoic carbonates, shales and sandstones while Upper Paleozoic rocks have been identified in
several isolated and scattered areas.
At the beginning of the Mesozoic Era the supercontinent Pangea broke up; opening the
Atlantic Ocean; and North American continent began to move westward pushing against the
thinner and heavier oceanic Pacific Plate. The heavier oceanic crust was forced under the lighter
continental crust forming a Subduction Zone and Island Arc with accompanying volcanoes. As
the Pacific Plate subducted under the North American Plate it melted and formed magmas. Some
of the raising magmas cooled closer to the surface whereas others cooled miles below the surface
forming granitic rocks of the Peninsular Ranges with accompanying metamorphic rocks. Some
other magma erupted forming volcanoes that led to the formation of volcanic derived
sedimentary basins. Continuous subduction of the oceanic crustal rocks for a hundred million
years caused low grade metamorphism forming metavolcanic rocks.
During Early Cenozoic, the peninsula was a relatively quiet place. The hills and
mountains were eroded forming gently rolling surface on the exposed rocks. Major rivers,
bearing gravel, flowed across the area from central Arizona to the Pacific Ocean. The North
American Plate overrode the East Pacific Rise and began the great rip-off. Coastal California and
Baja California began to slide northward along several parallel strike slip faults.
The mid-Cenozoic opening of the rift that become the Gulf of California, took tens of
millions of years. Volcanic and pyroclastic rocks spread over large areas of the peninsula during
the Miocene and Pliocene. A shallow Miocene sea spread across lowland areas of the southern
peninsula.
The present form of Baja California developed during the last 5-10 million years as the
continent opened forming the Gulf of California about 5 million years ago. The splitting of the
continent tilted the peninsula westward forming the asymmetric fault blocks of the main ranges
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of the Sierra Juarez, Sierra San Pedro Martir, Sierra la Giganta and uplifting other ranges such as
the Sierra la Asamblea and Sierra la Victoria.
Figure 12: The coastal mountains and alluvial valleys (Photo: The author, June, 1974)
Figure 13: The coastal mountains and alluvial valleys (Photo: The author, June, 1974)
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Figure 14: The Volcanic regions (Photo: The author, June, 1974)
Figure 15: The Volcanic regions (Photo: The author, June, 1974)
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Figure 16: The Volcanic regions (Photo: The author, June, 1974)
Figure 17: The coastal mountains and alluvial valleys (Photo: The author, June, 1974)
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Figure 18: A Cretaceous Cephalopod from Baja California from unknown locality (Photo: The
author, June, 1974)
Plate Tectonics and Geological Evolution of Baja California Peninsula
Brad Riney (paleontologist) and Lee Ellingson (artist) of the Ocean Oasis Field Guide
(2000: Website 5) of San Diego Natural History Museum provide the following account of the
geological evolution of the Baja California Peninsula and the Gulf of California in a simple
language. Movement along the Pacific and the North American crustal plate margin began to
break the Baja Peninsula and the western half of Southern California from mainland Mexico
around six million years ago, opening up the Gulf of California in the process (Figure 19). Since
then, the Pacific plate has moved some 330 km northwards carrying Baja California and
Southern California with it. A step by step summary of that process is illustrated below.
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Figure 19: The boundaries of the Pacific Plate and the North American Plate showing Baja
California Peninsula and western half of southern California to be part of the Pacific Plate
(Website 4).
Late Jurassic Period: 140 million years ago (Figure 20)
During the late Jurassic Period; western North America was with several offshore
volcanic islands and a deep oceanic trench. The Farallon Plate; shown here in black; slides under
the North American Plate. Volcanic islands fed by the partial melting of the Farallon Plate, due
to high pressure and temperature at great depth, form just east of the deep ocean trench that
marks the boundary between the North American Plate and the Farallon Plate.
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Figure 20: Paleogeography during Late Jurassic Period: 140 million years ago.
Middle Cretaceous Period: 80 to 110 million years ago (Figure 21):
Enormous thickness of continental and volcanogenic sediments were deposited upon the
North American Plate were compressed and subsequently elevated as a mountain range. The
massive basaltic slab of the Farallon Plate continued to slide underneath the North American
Plate. Giant magma bodies moved up into the overlying Jurassic sediments resulting in the
formation of granitic batholiths and metamorphic rock. New volcanoes were formed on top of
this great mountain range when the upward moving magma erupted near the surface.
Figure 21: Paleogeography during Middle Cretaceous Period: 80 to 110 million years ago.
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Late Cretaceous: 85 million years ago (Figure 22)
Mountain building began to slow down and constant erosion reduced the height of the
mountain ranges. There were giant Cephalopods in the ocean west of the mountain ranges
(Figure 18). The giant magma bodies subsequently cooled into large masses of igneous rocks i.e.
batholiths and continued erosion eventually brought them to the surface. The older volcanoes too
were eroded and were replaced by newer ones. The Farallon Plate continued to slide slowly
underneath the North American Plate.
Figure 22: Paleogeography during Late Cretaceous: 85 million years ago.
Figure 23: Paleogeography during Middle Eocene Epoch: 50 to 45 million years ago
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Middle Eocene Epoch: 50 to 45 million years ago (Figure 23)
Due to the constant erosion the late Cretaceous mountain ranges were reduced to hills.
Rivers flowed from the ancient mountains from Sonora, northwestern Mexico to the west coast
of present day southern California, USA and Baja California, Mexico.
Late Oligocene to Early Miocene Epoch: 30 million to 20 million years ago (Figure 24)
During the late Oligocene Epoch (30 million years ago) to the early Miocene Epoch (20
million years ago) all of the Farallon Plate had subducted underneath the North American plate.
The East Pacific Rise, where the Pacific Plate to the west and the Farallon Plate to the east were
spreading apart, soon began to subduct under the North American Plate. This increased
resistance due to subduction of the Pacific Plate under the North American Plate resulted in
renewed geological stress causing both the Pacific and North American Plates to fracture. Thus
began a stage for the formation of the Baja California Peninsula.
Figure 24: Paleogeography during Late Oligocene Epoch to Early Miocene Epoch: 30 million to
20 million years ago
Middle Miocene Epoch: 15 to 13 million years ago (Figure 25)
Much of the East Pacific Rise grinds beneath the North American Plate, thus stops the
subduction process. The eastern edge of the Pacific Plate got stuck underneath the western edge
of the North American Plate, while most of what is left of the Farallon Plate dives deep into the
Earth.
The Pacific Plate is moving to the northwest while the North American Plate is moving
westward. This difference of direction of movement causes great stress within both plates. The
Pacific Plate pulls the western edge of the North American Plate that is stuck to it away from the
rest of North America. This causes a strip of land 160 km to the east of the coastline to drop
down, forming a 700 to 800 mile long rift valley.
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Figure 25: Paleogeography during Middle Miocene Epoch: 15 to 13 million years ago
Late Miocene Epoch, 13 to 5 million years ago (Figure 26)
As the Pacific Plate continued its piracy of the western edge of the North American Plate,
the floor of the rift valley dropped below the sea level and created the Proto Gulf of California.
The Colorado River now flows into the Gulf of California used to flow to eastward prior to 5
million years. Tropical marine life flourished in the Gulf as evident from the extensive fossil
record from this time period. The Gulf of California extended northward to north of the
Coachella Valley in Southern California. The San Andreas Fault and other strike slip faults
became active during this time period, thus the newly created peninsula began to move
northward.
Figure 26: Paleogeography during Late Miocene Epoch, 13 to 5 million years ago
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Pliocene Epoch 5 to 2 million years ago (Figure 27)
The crust beneath the Gulf of California became extended beyond its capacity and tears
apart, so that magma welling up to fill the cracks begins to form new oceanic crust. Around 5
million years ago, the Colorado River changed its course and began to flow into the Northern
Gulf of California, filling it in with thick deposits of sediment.
Figure 27: Paleogeography during Pliocene Epoch 5 to 2 million years ago.
Figure 28: Paleogeography during Pleistocene Epoch to today, 2 million years to 0 million
years.
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Pleistocene Epoch to today, 2 million years to 0 million years (Figure 28)
Uplifting of Southern California and Baja California resulted in mountains to rise to over
3050 m. The delta region of the northern Gulf of California is filled in with 6 km of sediment
brought in by the Colorado River. Deep underneath the sediments, new oceanic crust continues
to form from upwelling magma. Some of this magma comes close to the present day surface to
cause hot springs and other geothermal phenomena. Power companies in California and Baja
California tap these hot spots to produce electric power.
Figure 29: The author admiring a species of cactus Ferocactus viridescens (Photo: Gordon D.
Wood, June, 1974).
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Figure 30: A species of barrel cactus Ferocactus cylindraceous (Photo: The author, June, 1974)
Figure 31: A typical lowland vegetation of northern Baja California (Photo: The author, June,
1974)
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Figure 32: Sunrise in northern Baja California (Photo: The author, June, 1974)
Figure 33: A typical lowland vegetation of northern Baja California, with a volcano in the
background (Photo: The author, June, 1974)
Figure 34: Cacti and Boojam trees (Fouquieria diguetti) in northern Baja California (Photo: The
author, June, 1974)
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Figure 35: Cacti and Boojam trees (Fouquieria diguetti) in northern Baja California (Photo: The
author, June, 1974)
Figure 36: Flora of northern Baja California dominated by Boojam trees (Fouquieria diguetti),
shrubs and Yucca plants in foreground. (Photo: The author, June, 1974)
Figure 37: Boojam trees (Fouquieria diguettiand Fouquieria columnaris), shrubs and Yucca
plants. (Photo: The author, June, 1974)
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Figure 38: Boojam trees (Fouquieria diguettiand Fouquieria columnaris) and cacti in the
northern Baja California. (Photo: The author, June, 1974)
Figure 39: A forest of Boojam trees (Fouquieria diguetti and Fouquieria columnaris) in the
northern Baja California. (Photo: The author, June, 1974)
Figure 40: Elephant trees (Bursera hindsiana) of northern Baja California (Photo: The author,
June, 1974)
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Endemic Plants of the Baja California Peninsula
The Baja California Desert has many endemic and endangered species of both animals
and plants. Due to long isolation during its geological past, topographic heterogeneity (Figures
31- 40), and diverse weather regimes it has high levels of endemism and diversity. Close to 500
species of plants, 4 amphibians, 43 reptiles, around 200 birds and over 50 mammals have
adapted to extremely harsh environments ranging from almost inhospitable hot and dry sand
dunes, to nutrient-deficient soils in the mountains (websites 6, 7 and 8). Almost 23 % of plant
species in Baja California are endemic (Rzedowsky 1988), particularly the plant families
Lamiaceae and Fouquieriaceae show considerable radiation within the ecoregion (Ramamoorthy
and Elliott 1993).
The different type weather of the peninsula includes Mediterranean-type, winter rainfall;
extremely arid and hot desert environments; and tropical, summer rainfall patterns. A wide range
of vegetation types include: coastal chaparral, conifer forest, low desert scrub (Figures 31- 40),
and tropical deciduous forest. The flora of the region has been estimated to be over 4,000 plant
species with approximately 30% of these known only from the peninsula of Baja California.
Many of these plants are quite unique, for example, Boojum Tree (Fouquieria columnaris
Figures 34-39); the giant Cardón cactus (Pachycereus pringlei); elephant trees (Pachycormus
discolor (Figure 40) and Bursera spp.); and large, succulent caudiciforms (Ibervillea sonorae)
(website 7).
The Baja California Desert ecoregion occupies the western portion of the Baja California
peninsula where elevation ranges from mountains (1000 - 1500m), high plains (300 – 600m), and
coastal dunes where climate is essentially dry with variable temperature. The isolation of this
long and slender peninsula, and its proximity to the sea, causes humidity, and keeps temperatures
more or less stable throughout the day. Thick-stemmed trees and shrubs grow on rocky volcanic
soil cover the higher parts of the mountain ranges. Many species of cacti (Figures 29, 30, 34)
occur here and dominant species vary with elevation. Epiphytes grow in low, humid areas are
part of perennial vegetation. Areas formerly submerged under the sea are now covered by highly
salt and alkaline tolerant plants (website 8).
Visit website 9 to see images of endemic plants of Baja California.
Acknowledgements: I sincerely thank Dr. Aureal T. Cross, Professor Emeritus of Geology, Biology and Plant
Pathology, Michigan State University (MSU) for taking me to this memorable trip to Baja California, Mexico.
During my graduate students days at MSU I took several such long geological excursions with Prof. Cross and his
students to various parts of the United States especially to the Rocky Mountains, western and southern regions of
America. I also thank my MSU classmates Dr. Gordon D. Wood, Retired Senior Scientist, AMOCO Production
Company, Houston, Texas, and Professor Enrique Martinez-Hernandez, Instituto de Geologia, Universidad Naciona
lAutonoma de Mexico (UNAM), Mexico City for heated exchanges and arguments on the geology and biology of
this region. Mr. Christopher Cross of Denver and Ms. Sue were great company during this long trip. It was a great
learning experience for all of us and we had enjoyed this trip immensely.
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Suggested Readings:
Johnson, S. E., Paterson, S. R., Fletcher, J. M., Girty, G. H., Kimbrough, D. L., and MartinBarajas, A. 2003. Tectonic Evolution of Northwestern Mexico and Southwestern USA. The
Geological Society of America Special paper 374. Boulder, Colorado, USA. 478 p.
Gastil, R. G., Phillip, R. P. and Allison, E. C. 1975.Reconnaissance Geology of the State of Baja
California. Geological Society of America Memoir140, 170 p.
Minch, J. Minch, E. and Minch, J. 1998. Roadside Geology and Biology of Baja California,
ISBN 0-9631090-1-4, JMA Press, P.O. Box 4244, Mission Viejo, CA 92690-4244
Ramamoorthy, T.P., and M. Elliott. 1993. Lamiaceae de México: diversidad, distribución,
endemismo y evolución. Pages 501-526 in T.P. Ramamoorthy, R. Bye, A. Lot, and J. Fa, editors,
DiversidadBiológica de México.Orígenes y Distribución. México: Instituto de Biología, UNAM.
Rzedowski, J. 1978. Vegetación de Mexico. Editorial Limusa. Mexico, D.F., Mexico.
Web References
Website 1:
http://upload.wikimedia.org/wikipedia/commons/5/5f/Baja_peninsula_%28mexico%29_250m.jp
g
Website 2:
http://www.google.ca/search?q=geography+of+baja+peninsula&hl=en&tbm=isch&tbo=u&sourc
e=univ&sa=X&ei=DJhlUeHkH4Se2gX_5oH4CA&ved=0CEIQsAQ&biw=1280&bih=583
Website 3:http://math.ucr.edu/ftm/bajaPages/Geology.html
Website 4: http://commons.wikimedia.org/wiki/File:Pacific_Plate_map-fr.png
Website 5: http://www.oceanoasis.org/fieldguide/geology1.html
Website 6: http://www.discoverbajacalifornia.com/baja-geographical-summary.php
Website 7: http://bajaflora.org/Bajadocs/BajaFloraIntro.htm
Website 8: http://worldwildlife.org/ecoregions/na1301
Website 9:
http://www.google.ca/search?q=endemic+plants+of+baja+california&hl=en&tbm=isch&tbo=u&
source=univ&sa=X&ei=pNRkUVDqP62QXoz4DgCA&ved=0CG0QsAQ&biw=1280&bih=583
About the Author
Dr. Arun Kumar is an Adjunct Professor, Department of Earth Science, Carleton University
1125 Colonel By drive, Ottawa, ON K1S 5B6, Canada.
Email: [email protected]
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