New Passage “Absolutely Breathtaking”
Fort Stanton Cave has been known and used by Native Americans, white settlers, and modern recreational cavers for quite some time. In the 1960s, a group of volunteer cave enthusiasts rehabilitated the cave and, since then, citizen caretakers have worked with the BLM to manage and generally care for it. In 2009, the cave system and the area around it, totaling 25,080 acres, were given NCA designation in order to protect its scientific, natural and cultural resources.
Reading clues such as the pattern of air flow within the cave, experienced cavers had long suspected that sections of the Fort Stanton cave system were yet to be discovered. This hunch was confirmed in 2001 when a three-person volunteer team broke through to a brand new passage. It was “absolutely breathtaking,” according to Dr. Penny Boston. On her first visit, she recalled, “We gasped at the beauty of it. Just looking at it, it was obvious that it was just extraordinary. It was unlike anything ever reported in any other cave in the world.”
Further exploration had to wait while the BLM put together a management and exploration plan and while a safer route was established. The original route was arduous and risky; it involved belly crawling through broken, unstable limestone rock for periods of up to 12 hours, one-way. Once a safe passage was opened, exploration and study began in 2005.
Geologic History Revealed
One of the most important features of the new discovery from a scientific perspective, according to Dr. Boston, is the way the geologic history of the area is set down in layers undisturbed by humans. “The cave itself is like a time capsule of earlier climate eras.” She says. “It’s like a storybook - you can essentially peel back the layers of time in this cave, like pages in a book, and read the history of the hydrology and the climate of the region.”
Between the time of the cave’s original creation and when the calcite was put in place, there is evidence of multiple flooding events. “Underneath the white calcite layer, there are thick deposits of beautifully water-sculptured river pebbles that come from a number of external geological sources, and they can be traced to metamorphic material in some of the older mountains nearby,” Boston says. Volcanic materials can be similarly traced to nearby mountains as well. “So even though we don’t know exactly when open passages leading into Snowy River existed, or how big they were, we do know they were there because we have these wonderful mud and river deposits underneath the calcite within the cave. And with that amount of flooding, we suspect it was when the climate was radically different than it is today. A guess would be mid-Pleistocene when the whole earth was much cooler and wetter, and the deserts in the Southwest were smaller.”
The calcite feature that created the “Snowy River” effect was a relatively recent addition, “sort of like icing on a cake.” It appears to be about 900 years old, according to Boston. At first, scientists thought it was formed in a single event, as calcite precipitated out of fluid trapped in the system. But researchers now are beginning to think there was a sequence of events linked to multiple flooding episodes that created the calcite deposits over time. Evidence for this is being obtained by analyzing core samples, doing age-dating and looking at the organic clay content and fluorescent properties of different materials that came in with different flooding episodes.
Part of a Larger System
Scientists are trying to determine not only how the calcite layer was formed in the cave, but also how the cave hydrology is connected to the drainage of the surface lands around the cave. “Caves do not exist in isolation, they are part of an overall natural system,” says Boston. “The designation of the Fort Stanton, Snowy River Cave as part of the BLM’s National Landscape Conservation System is a landmark in terms of conservation because the NLCS takes into account the fact that individual features, such as caves, exist as part of an overall system, and looking at the overall system is critical to our understanding of our future.”
Boston says the hope is that scientists can better understand the precise details of how climate mechanisms interact over time; the intact mineral record of this cave will add significantly to the body of knowledge about the climate history of the desert southwest where drying has occurred over the past 10 - 20,000 years.
Another focus of Boson’s interest is the geomicrobiology within the cave. With her colleague, microbiologist Diana Northup (of the University of New Mexico), and several graduate students, Boston is studying the indigenous native microbial inhabitants of the cave system. She describes the striking black patches on the cave walls – manganese oxide deposits with clays that are rich in microorganisms that oxidize manganese compounds. “We believe these black coatings are the result of extensive microbial activity. I have isolated many of these, and what struck me is that these are still very active microbial communities – not some relics from an earlier climate regime. We are looking at their DNA to determine their identities; are they known to science in other environments, or are they brand new? Our results so far indicate a mixture. Some strains we know from other subsurface environments, but many others are completely novel and previously unknown to science.”
Some of these newly-discovered microbes may have commercial applications. For example, they could potentially help remediate manganese contaminated waters. Manganese is common in many kinds of bedrock so manganese can be abundant in water sources derived from bedrock. Some of the newly-discovered microbes oxidize manganese that is dissolved in water, producing as a byproduct a more solid form of manganese that precipitates out of the water table. This could help reduce unwanted manganese in water sources. There also may be applications for biologically based waste-treatment plants using cave organisms that can remove hydrogen sulfide from the water at a wide range of temperatures.
Studying Human Impacts
Boston and Northup have another longstanding interest in the microbiology in caves – one that has direct resource management applications. They are studying the impacts of human exploration on the native micro flora in caves. They and their colleagues want to determine how much microbial contamination humans introduce into caves, how much of that can be detected, and how long the non-native organisms might survive in this very different environment.
Boston and Northup have studied human impacts in other caves and from these earlier studies, they believe it is clear that impacts from long duration trips are minimized when people remain in camps and on designated trails. Contamination drops off in areas that are distant from designated trails.
Fort Stanton Snowy River provides an unparalleled opportunity to study human impacts in a cave where humans have had very limited, highly-controlled access only for a few years. “Since 2001, we know who has gone into this cave, where and how often – we have trip reports. We now are trying to get a handle on how much contamination they have introduced, how long does it persist and how do we control it?” Boston and Northup are overseeing an ongoing monitoring program to look at human impacts over long periods of time at the Fort Stanton cave system. This will provide an important management tool the BLM can use in this and other caves.
There are myriad opportunities for scientific discovery and study in this major underground resource managed by the BLM. Coring down through the layered mud deposits to access ancient pollen, for example, can provide clues about the above ground vegetation during previous eras. Many other studies touch on questions about past climate and water resources, the history of vegetation, and exotic microorganisms in the velvety black coatings on cave walls. “There is still so much to be discovered. The amount of science that can be done in this system is far greater than what we have the people or the money to do.”
The dedicated volunteers of the Fort Stanton Cave Study Group are a unique and compelling part of the story of Snowy River. The Study Group Manager has been caving at Fort Stanton since the 1960s and now coordinates exploration activities while mentoring the next generation of volunteer cavers. Among the group members, in addition to Dr. Boston, are a retired USGS hydrologist who was on the Snowy River discovery trip and whose homemade resistivity machine now helps predict where new cave passage is located, a retired math teacher who engineered and supervised the digging of a safer route into Snowy River, and a professional welder who fabricated cave gates to protect the cave.
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