Bulletin 156—Natural history of El Malpais National Monument

Compiled by K. Mabery, 1997, 188 pp., 12 tables, 176 illustrations (including 39 black-and-white photos and 85 color photos), glossary.

The name "El Malpais" comes from early Spanish explorers. Literally it means "the bad country." The area, now known as El Malpais National Monument, has been a laboratory for natural history studies since the 1920s. This bulletin contains 14 chapters written by volcanologists, mineralogists, botanists, cave ecologists, zoologists, and others, representing more than 20,000 hours of field work from 1970 through 1996. There's something for everyone:

• Color photo atlas of volcanic landforms in El Morro area
• Comparative analysis of six Quaternary dating techniques as applied to lava flows
• Geologic history of Zuni-Bandera volcanic field
• Lava tube caves: formation and ecology-mineralogy, fauna, cave ice
• Lava flow plant and animal communities
• Rare, old trees including the oldest known living Douglas fir in North America
• History of wildfire
• History of human occupation
• Glossary of geological and biological terms
• Historic photos, maps, charts, species lists, and much more

For this retrospective glimpse at the findings made during the 1940s in the Grants Malpais, the author concentrates on some of its features that he thought illustrates the uniqueness of the area. When the National Monument and Conservation Area were established in 1988, one of the National Park Service's first goals was to untangle the complex stories of El Malpais and their relationship to the global picture. Before the Park Service could develop interpretive materials, unanswered questions about unique features of the Monument needed scientific investigation. Beginning in 1989, the Park Service recruited and encouraged a broad range of scientists to delve into the secrets of this unique volcanic landscape.

El Malpais is located on the southeast edge of the Colorado Plateau, most of which consists of horizontal or slightly tilted sedimentary strata. There are a few intrusives forming mountains in the central part of the plateau and older volcanic mountains along the southern edge of the Plateau. In contrast, the only volcanic fields on the Plateau are the Sunset Crater region in Arizona and El Malpais. Of the two, El Malpais contains one of the longest sequences of volcanic activity in the U.S., from about 700,000 to about 3,000 years ago.

  Having 15 or more lava flows in less than one million years contributes to other unusual features. Each flow resulted in a new land surface. From about 100,000 to 3,000 years ago, a new lava surface appeared about every 7,000–25,000 years. Immediately after the formation of these new surfaces weathering began to form primitive soils and plant invasions occurred. Caves in these flows contain important clues to the transport mechanisms of the lavas and development of minerals. The El Malpais lava flows thus chronicle very recent ecological successions in an area which generally has soils and habitats dating back millions of years.

Since many of the lava flows are very rugged and have not yet developed continuous soils, plant and animal communities have been naturally protected from logging, domestic grazing, fuelwood gathering, and other impacts of modern man. Trees that died hundreds of years ago are still laying on the rugged lava. Fragile plant communities flourish in collapsed depressions in the lava and cave openings. The trees reveal an accurate record of rainfall and fire back to the time of Christ, while the potential importance and lessons to be learned from some of the isolated vegetative communities is only just beginning to come to light.

Recent scientific studies have ranged far beyond the scope of this bulletin. It seems that every time one line of investigation was about to be concluded, a new question would arise. This circular is a compilation of some of the more significant and basic findings of the more than 30 scientists who worked at El Malpais National Monument since its inception in 1988. The research of the others is no less significant, and in some cases has contributed to the chapters that are in this bulletin.