By Jorge Alberto Miros and Miguel Agustín Téllez

The biodiversity or biological diversity is a concept used to describe the landscape. However, the geodiversity or diversity of geological elements (such as rocks, minerals, fossils, soil and the process that shape the earth, including human activity) is often ignored, despite it explains the geological and biological landscape that surrounds us.

Figura 4. Las cuevas volcánicas sirvieron como resguardo para los nativos Kiliwas. El piso y alrededores están cubiertos de concheros, acumulaciones de conchas de moluscos que recolectaban y consumían como parte importante de su dieta.

Just like an artist, nature has chiseled the geological scenery that we observe. Millions of years of history are registered in earth rocks, as well as the rise and evolution of the living beings is recorded in the fossils on these rocks.

Preserving the history of Earth, the record of life on it, and the rise of the human being and its culture are indisputably important. For this reason, the geodiversity studies are needed to recognize the geological heritage of a region, in other words, the sites that are conservation priority sites because of their historical, scientific, educational and cultural importance and to encourage  sustainable development through tourism, like the San Quintín Bay and its surrounding areas (figure 1).

Figura 1. Bahía de San Quintín y zonas aledañas.

Geodiversity predetermines biodiversity and it is related to the culture 

The distribution of flora and fauna is strongly influenced by the physical environment that drives from geodiversity (figure 2). Likewise, geodiversity is related to cultural heritage, since human beings, from the beginning, have had the need to analyze the geological scenery to gather materials and elaborate all kinds of things, from tools to buildings. Therefore, the biological and cultural variety depend to a large extent on the geological characteristics of the landscape.

La siempreviva (Dudleya Anthonyi) es una especie de suculenta endémica del Campo Volcánico de San Quintín que crece sobre las rocas de basalto (roca con alto contenido de magnesio y hierro).

The aridity of Baja California lets us appreciate the geological scenery on which the life of the ancient inhabitants depended. Its uncommon features favored a “cultural freezing” in the prehistoric era, when native semi-nomads survived by benefiting from rocky safeguards to shield themselves, and by making gadgets of carved stone, mainly used for hunting and harvesting. In addition to that, they used natural mineral pigments in their artistic expressions like the cave paintings. 

The geological and cultural heritage of the San Quintín Bay and surrounding areas

On a regional level, the San Quintín Bay stands out for its versatility of landscapes. It sits on a peculiar volcanic field, unique in the peninsula of Baja California, which originated by a process called “intraplate volcanism”. Volcanoes or ash cones are formed by the upward flow of molten rock that originated on the asthenospheric mantle (figure 3), on the end of the Pleistocene (~180 thousand years).

Xenolitos ultramáficos constituidos de olivino, ortopiroxeno y clinopiroxeno. Estas rocas se forman a una profundidad de 75 kilómetros, durante su ascenso a la superficie estuvieron expuestas a una gran presión (100 MPa), lo que imprimió en ellas características únicas que sólo se han observado en dos lugares del mundo: Montferrier, al sur de Francia y en la bahía de San Quintín, Baja California (Cabanes y Mercier, 1988).

Volcanic caves, basalt spills, pillow lavas, tombolos, marshes, dunes, coastal cliffs and geosymbols are part of the geological features of the bay. Associated to them, there are paleontological sites with remains of mammoths and mollusks fossils, as well as a high number of shell midden archaeological sites on its shores (figure 4).

North of the bay, there are evaporite or salt deposits close to Laguna Figueroa, where microbial mats originate structures called stromatolite. These structures are unique in the region, and have a very high scientific value due to their similarity to the first living beings that appeared 3,500 million years ago. Because of this, studying them allows us to have a better understanding of how life on Earth emerged. 

South of the bay, some dune fields, marine terraces of the former sea level, and amazing formations such as La Lobera stand out (figure 5).

La Lobera (El Desfondadero) es una cueva colapsada moldeada por la constante erosión generada por las olas y el viento sobre las rocas sedimentarias. Su interior es un refugio para la foca (Phoca vitulina).

El Rosario, the oldest town in Baja California, is surrounded by whimsical formations in sediments deposited in the Late Cretaceous (~75 million years) that contain invertebrate marine fossils like ammonites, primitive land mammals, petrified wood and dinosaur bones (figure 6). Furthermore, the cultural heritage of the area holds prehistoric remains and ruins of the mission period.

Figura 6. Reconstrucción e interpretación del dinosaurio terópodo Labocania anomala (Molnar, 1974). Este ejemplar sólo se ha registrado en los estratos del Grupo Rosario (Formación Bocana Roja). Imagen modificada de García-Mora (2013).

Geotourism and geoparks

Altogether, these landscape features represent a geological and cultural heritage of great relevance on a national and international level that deserves to be preserved. However, it is also possible to make use of it in a sustainable way for the benefit of the local community.  In this sense,  geotourism is a conservation scheme that promotes the benefit from the landscape, where the tourist can get to know it, appreciate it, and value the history of Earth by stimulating activities that are favorable to its conservation and encouragement of the local economy.  On an international level, geotourism has been pushed forward under the scheme of UNESCO Geoparks, which promotes the conservation of high-value heritage landscapes through geoturism based on community participation.

Creating a geopark, that could even be recognized by the UNESCO, in the San Quintín Lagoon Complex, the San Quintín volcanic area, and El Rosario is feasible because of  its geological, biological and cultural relevance, it is feasible to create a geopark in the San Quintín Lagoon Complex, the San Quintín volcanic area, and El Rosario altogether; a geopark that could even be recognized by the UNESCO. In order to accomplish this, the active participation of the local population, non-profit organizations and government will be needed.

About the authors

  • MS Jorge Alberto Miros Gómez. Holds a bachelor’s degree in Environmental Sciences and a master’s degree in Coastal Oceanography oriented to the coastal geology and geologic information systems. Throughout his career, he has developed environmental education, geological and cultural heritage conservation projects in northwest Mexico.
  • Miguel Agustín Téllez Duarte, PhD. He is a professor-researcher at the Coastal Geology Department of the School of Marine Sciences at the Autonomous University of Baja California in Ensenada. His extensive expertise includes topics related to paleontology, stratigraphy and y taphonomic processes. He has also participated in the development of several projects oriented to the dissemination of the geological, paleontological and cultural heritage of Baja California.

Bibliography

  • Cabanes N., and Mercier J. C.C. 1988. Insight into the upper mantle beneath an active extensional zone: the spinel-peridotite xenoliths from San Quintín (Baja California, México). Contrib Mineral Petrol. Vol. 100. pp. 374-382.
  • Carcavilla Urquí, L., Durán Valsero, J.J., and López Portillo, J. 2008. Geodiversidad: concepto y relación con el patrimonio geológico. GeoTemas. Vol. 10. pp. 1299-1303.
  • García Mora, R. 2013. México Prehistórico, el relato jamás contado de los dinosaurios de nuestro país. Artwork for Quo Magazine August, Labocania anómala. http://romangm.com/mexican-dinosaurs-quo-magazine-august-2013/
  • Gastil G., Phillips R., Allison E. 1975. Reconnaissance geology of the state of Baja California. The Geological Society of America Inc. Memoir. Vol 140. 92 p. 
  • Gray, M., 2004. Geodiversity, valuing and conserving abiotic nature. Great Britain: John Wiley & Sons Ltd, Englad. 450 p. ISBN: 0-470-84895-2
  • Guía-Ramírez A. Y Olivedo-García F. 2012. The fauna of the Pleistocene and early settlers in Baja California. SCA Proceedings, Vol. 26. pp. 71-77.
  • Hose, T.  2006. “Geoturismo” europeo. Interpretación geológica y promoción de la conservación geológica para turistas 1999.
  • Lhur J. F., Aranda-Gómez J. J., Housh T. B.  1995. San Quintín Volcanic Field, Baja California Norte, México: Geology, petrología and geochemistry. Journal Of Geophysical Research. Vol. 100. pp. 10,353-10,380.
  • Margulis L, Barghoorn E. S, Ashendorf D, Banerjee S, Chase D, Francis S, Giovannoni S, Stolz J. 1980. The microbial community in the layered sediments at Laguna Figueroa, Baja California, Mexico: does it have Precambrian analogues? Precambrian Res. Vol. 11. pp. 93 -123.
  • Margulis L, Grosovsky B. D. D, Stolz J. F, Gong-Collins E. J, Lenk S, Read D, Lopez-Cortés A. 1983. Distinctive microbial structures and the Pre-Phanerozoic fossil record. Precambrian Res. Vol. 20. pp.  443-477.
  • Molnar, R. E. 1974. A distinctive theropod dinosaur from the Upper Cretaceous of Baja California (México). Journal of Paleontology. Vol 48. (5). pp. 1009-1017.