Desert Messenger

12 www.DesertMessenger.com September 16, 2015 Dotting the landscape with red and black cone-shaped hills, the cinder cones rise up out of the Co- conino Plateau. Rivers of huge, jagged black boulders wind their way through the forest. Rugged bluffs tower over the scrubby juni- pers, grasses, and wildfl owers that call the plateau home. Beneath the landscape, tube-like caves meander underground, keeping their secrets hidden from the world above. This is the panorama of the San Fran- cisco Volcanic Field in Coconino County near Flagstaff. The San Francisco Volcanic Field consists of over 600 volcanoes ranging in age from 1000 years old to ancient craters dating back over 6 million years. Most of the volca- nic peaks are cinder cones of basalt. Large fl ows and domes of basalt, rhyolite and dacite are also preva- lent. Basaltic lava fl ows are of two main types, Pahoehoe and A'a', and derive their names from the tra- ditional language of the Hawaiian By Jenn Jedidiah Free for RocksInMyHead™ Lava - The Hot and Cold of It people. A'a' (pronounced Ah – ah) is the most common type of fl ow forming huge fragmented rivers of jagged boulders, crags, crevices, and cavities. Pahoehoe (pah- hoy-hoy) means "rope-like" and is character- ized by a more smooth, billowy sur- face that resembles bundled or coiled ropes. In an A'a' lava fl ow, the lava cools quickly as it travels slowly over the ground surface and cracks, folds, upheaves, twists, and bends as it so- lidifi es. Pahoehoe lava typically cools more slowly and travels quickly, un- dulating and churning in a consis- tent, steady fl ow. Pahoehoe lava often fl ows in a dome- like channel. Lava fl ows up to the surface through a vent. As the lava travels along the ground, cooling and solidifi cation around the sides, bot- tom, and top of the fl ow produces a conduit of rock called a lava tube. The dense, black insulating layer keeps the interior of the tube relatively hot, about 1150 to 2000 degrees, and in- sulates the lava inside the tube from further crystallization, enabling it to fl ow great distances before cooling and solidifying. Molten lava can fl ow through a tube at a speed of about 35 miles an hour, creating a churning, turbulent river of liquifi ed rock. The turmoil of bubbling lava generates spatter fragments, fl ow ripples, high lava marks, icicle shaped lava stalac- tites, and other very interesting and unique formations left behind after the tube is empty of its liquid fury. In stark contrast to the 2000 degrees of a fl owing tube, dormant tubes are cold. The dense composition and dark color of the tube walls, now de- void of an internal heat source, insulate the air within the tube from the sur- face temperature. Lava tube caves typically maintain an interior temper- ature of about 35 to 40 degrees, even on days when the sur- face temperature is in the 90's. Ice can be found year round in many lava tubes, such as Lava River Cave just outside Flagstaff. Lava River Cave is the longest lava tube in Arizona. It was formed some- time between 650,000 and 700,000 years ago, during the most recent eruptions of the San Francisco Vol- canic Field. While Sunset Crater and other cinder cones and fl ows of that period were well known since an- cient times, Lava River Cave was only discovered in 1915. Lumberjacks found the cave while felling trees in the forest near Flagstaff, and word of it quickly spread to the homestead- ers in the area who would visit the cave to collect ice in the summer- time. Later, the cave became known for its amazing geologic features and unusual rock formations. If you come through Flagstaff on your way back to Quartzsite, be sure to stop at the Lava River Cave. Be prepared with sturdy shoes or hiking boots, cool weather gear, and a fl ash- light as you explore this otherworld- ly landscape of molten rock frozen in time. Another great stop is Sunset Crater National Monument. There you will experience amazing forma- tions of Pahoehoe and A'a' lava fl ows and awe-inspiring cinder cones, set amongst the beautiful scenery of Co- conino National Forest. To see more photos of Lava Tube Caves, Pahoehoe and A'a lava for- mations, visit JennJedidiahFree. com and view our photo journal of the lava tube caves and formations at Craters of the Moon in Idaho. We have several different types of lava rock in stock, including the rare Blue Dragon lava from Idaho, as well as books, maps, tools, equipment and more for all your geology, rock- hounding, prospecting, and lapidary needs. We will be open in Quartzsite at Rice Ranch A37 at the end of Octo- ber. Meanwhile, you can order online at www.RocksInMyHead.com, and like us on Facebook. Happy Travels and we'll see you soon in Quartzsite! ADVENTURES WITH ROCKS 431 E. Main Street, Quartzsite 928-927-7900 QuartzsiteChiro.com Jennifer Maltby, D.C. Open Year-Round New hours: Mon. and Thurs. 9am-2pm Chiropractic Care Now Open in Quartzsite! RJK CONSTRUCTION • No Job Too Small • Commercial • Residential • Remodeling LOCALLY OWNED & OPERATED Call Roy and Bob 928-345-5616 AZ License #13-1743 (Not a licensed contractor) $ 350.00 per denture when purchasing an upper and lower Dental Laboratory Service, LLC Call: 623-444-4013 Goodyear, AZ http://www.DLSAZ.com FREE CONSULTATIONS Same Day Dentures and Custom Premium Partials and Dentures • US Military Trained with 30 plus Years Experience • 1000's of Satisfi ed Customers • Extractions & Implants by Licensed AZ Dentist DENTURES

• Cover