Geology

                    Orient Land Trust
                                   Valley View Hot Springs
                                   Email: info@olt.org

Geology

The Orient Mine is an area of scientific interest because of the unusual geology which caused the iron deposit to form. The hot springs area is interesting geologically because of the fault line which caused the hot springs to surface. Over the past three decades at least three people have pursued graduate degrees based on research of the mine or fault zone area. More recently, in June 2001, one of the Board members, Dr. James McCalpin, conducted a college level course in the field studying the geology of the fault scarp running through the property. A trench has been dug across the fault line on the property to enable students, professionals and other lay persons to learn about the geology of the fault zone. Dr. McCalpin will be developing associations with area public schools to provide opportunities for students to learn about the geologic features of the trust lands.

Where Valley View Water Comes From
by Jim “Dr. Rocks” McCalpin

The water that bubbles up through the floors of all the soaking pools at Valley View (and warms all our world-class posteriors) has an interesting and complex history. Basically, the warm water rises up along the Sangre de Cristo Fault (SCF). Across this fault the bedrock formations on the east side of the fault (for example, the quartzite that outcrop along the trail to the Top Pond) have been down-dropped as much as 16,000 feet down to the west. The fault has continued to slip in geologically recent times, and is classified as Colorado’s most active and longest active fault!

In the fault zone itself, the bedrock formations on either side have been crushed and rotated by this slippage, and this has created a near-vertical shear zone of interconnected void spaces about two to five feet wide. Water can flow much more easily through the open void spaces in the fault zones than through the intact, unsheared bedrock outside the fault zones. Because the fault zone is more permeable than the adjacent rock walls, it tends to intercept deep westward groundwater flow from the Sangre de Cristo Range to the San Luis Valley, and acts like a giant drain, similar to the one you (hopefully) have around your house foundation. This deep groundwater is warm because it has picked up heat from the warm rocks beneath the mountains.

The intercepted warm water then rises upward in the fault zone toward the earth’s surface and emerges at Valley View. The springs are probably localized at The View because an east-west fault in the mountains intersects the north-south SCF, creating a small but severely crushed intersection zone.

The spring flow is made of two water components: (1) the deeper, warmer groundwater that becomes heated, intersects the fault zone at depth, and then rises up in the fault zone (geothermal water), and; (2) the shallow, cooler water from infiltrating rain and snowmelt (called meteoric water) that never penetrates more than a few tens of feet into the earth’s surface. The flow volume of deep geothermal water is essentially constant through the year, but the influx of cooler meteoric water varies with the amount of rain or snowmelt that infiltrates the ground.

In most mountainous regions, water infiltration into the ground reaches a maximum in March to May of each year, as all the previous winter’s snow melts. At that time of year, the springs should flow with the most volume, but the water is cooler because of the addition of the large component of cool meteoric water. This effect should be largest at the Top Pond, which catches the most mountain runoff, and should be less at the lower ponds. Conversely, in mid-winter there is essentially no water infiltrating into the ground (it’s all frozen), so the spring flow is reduced in volume but it’s usually hotter, because it is almost totally composed of the deep circulating, geothermal water component.

In addition to serving on OLT Board of Directors, Dr. McCalpin wears many other hats including: President, GEO-HAZ Consulting, Inc. www.geohaz.com; Director, Crestone Science Center; Research AssocProf., Utah State University.