The Needles in the Mohave Mountains of Arizona present a unique geological character.
Here’s an overview of the geology of this area:
Location and Formation
The Chemehuevi Mountains are located in southeastern California and extend into the Mohave Mountains in Arizona. This range is part of the Basin and Range Province and is characterized by its dramatic elongated mountain ranges separated by flat valleys or basins.
Erosional Features
The Needles within the Mohave Mountains are likely a result of extensive erosional processes that have sculpted the landscape over millions of years. Weathering and erosion, driven by temperature fluctuations, water action, and wind, have exposed the harder, more resistant rock formations. These processes create the sharp, needle-like spires and rugged terrain typical of the area.
Ecological and Environmental Significance
The Mohave Mountains’ geological diversity supports various habitats and is significant for biodiversity. The area’s unique geology affects soil composition, water availability, and vegetation types, all of which contribute to the ecological complexity of the region.
These geological and erosional processes have given the Mohave Mountains their distinctive rugged appearance, making them a notable example of the dynamic Earth processes at work in the desert environments of the American Southwest.
A “hanging dune” is a specific type of sand dune that forms on the leeward side of a hill or mountain, typically above the general level of the surrounding terrain. These dunes are essentially perched above other landforms, often appearing as though they are hanging on the slopes.
Here’s how they develop and some characteristics:
Formation
Hanging dunes primarily form in areas with significant wind activity where the topography causes the wind to deposit sand on steep slopes rather than just along flat surfaces. This process involves:
Wind Patterns: Strong, consistent winds carry sand from lower areas.
Obstacle Impact: When these winds encounter steep slopes or cliffs, their upward deflection causes a reduction in wind speed, dropping the sand and forming a dune.
Accumulation: Over time, more sand accumulates, stabilizing despite the steep slopes due to vegetation or moisture, further building the dune.
Characteristics
Location: They are typically found on the sides of hills, cliffs, or within mountain ranges where wind patterns are disrupted by the topography.
Stability: These dunes can be quite stable if vegetation anchors the sand, or they can be transient and shift with changes in wind patterns.
Ecological Impact: Hanging dunes can create unique microenvironments that support specialized plants and animals adapted to these specific conditions.
Geologic and Ecological Significance
Indicator of Wind History: The presence and orientation of hanging dunes can provide clues about historical wind directions and strengths.
Biodiversity: These dunes can host unique species that have adapted to the niche environments created by the unusual moisture and temperature conditions on the slopes.
Conservation: Due to their unique nature and the specialized ecosystems they support, hanging dunes can be important areas for ecological studies and conservation efforts.
Hanging dunes are less common than other dune types and require a unique set of environmental conditions to form and persist, making them particularly interesting for geologists and ecologists studying aeolian (wind-driven) processes and desert ecosystems.
The Mojave River Fan, located in the Mojave Desert of California, is an extensive alluvial fan formed by the deposition of sediments from the Mojave River. This geological formation is significant due to its role in shaping the landscape and hydrology of the region. Here are some key aspects of its geology:
Formation and Composition:
The fan comprises sediments such as sand, gravel, and finer materials from the surrounding mountains carried down by the Mojave River and its tributaries. These sediments are deposited primarily during periods of high water flow, typically associated with rainfall events.
The materials are sorted by size, with coarser materials settling closer to the mountains and finer materials spreading further onto the fan.
Geological Features:
The Mojave River Fan is characterized by its radial pattern, spreading from where the river emerges from the mountains onto the flatter desert plain. This spreading creates a broad, gently sloping surface.
The fan is divided into different lobes or segments, each representing periods of active deposition under varying climatic and hydrologic conditions.
Hydrology and Erosion:
The fan plays a critical role in the desert’s hydrology, influencing groundwater recharge and the distribution of aquifers. Water percolates through the porous sediments, replenishing groundwater reserves.
Erosional processes also shape the fan, as water channels carve out new paths during floods, redistributing the sediments.
Environmental and Climatic Influences:
The formation and evolution of the fan are closely linked to climatic changes over geological time scales. Periods of wetter climate have led to increased sediment load and fan expansion, while drier periods have seen reduced activity.
Human Impact and Studies:
The area has been the subject of various geological and environmental studies, especially concerning water resource management and hazard assessment due to its proximity to populated areas and infrastructure.
Understanding the geology of the Mojave River Fan is crucial for managing natural resources and mitigating natural hazards in this part of the Mojave Desert.
The Sierra Nevada Batholith is a large, composite body of igneous rock in the Sierra Nevada range of California. This batholith, mainly composed of granitic rock, was formed during the Mesozoic era, particularly from the Late Jurassic to the Late Cretaceous period. It extends over a vast area and is exposed over approximately 400 miles along the western slopes of the Sierra Nevada.
The formation of the Sierra Nevada Batholith is tied to the subduction of the oceanic Farallon Plate beneath the North American Plate. As the plate subducted, it generated magmas that rose and solidified to form the granite that characterizes this batholith. The emplacement and cooling of these granitic magmas over millions of years have significantly influenced the region’s geology and topography.
Geologically significant and visually striking, the Sierra Nevada Batholith is a major feature underlying the rugged landscapes of Yosemite Valley and other parts of the Sierra Nevada. It is important not only for shaping the physical landscape but also for contributing to understanding the geological processes of mountain building and magmatic intrusions.
The information about the Sierra Nevada Batholith is based on well-established geological knowledge and does not come from a specific source.
For in-depth information about the Sierra Nevada Batholith, the following sources are highly recommended:
“Geology of the Sierra Nevada” by Mary Hill – This book provides a comprehensive overview of the geological history of the Sierra Nevada, including detailed discussions on the formation of the Sierra Nevada Batholith.
“Roadside Geology of Northern and Central California” by David Alt and Donald W. Hyndman – This guidebook includes accessible explanations and descriptions of geological features along various routes, including those that expose parts of the Sierra Nevada Batholith.
“The Geologic Story of Yosemite National Park” by N. King Huber—While focused on Yosemite, this publication offers valuable insights into the granitic formations making up the Sierra Nevada Batholith and their significance in the park’s natural history.
Scholarly articles such as the Journal of Geophysical Research or Geological Society of America Bulletin often publish research on the Sierra Nevada Batholith, discussing its formation, composition, and role in regional geology.
These sources will provide a detailed and accurate understanding of the Sierra Nevada Batholith, suitable for educational and research purposes.
1910 Columbia Street in Goldfield, Nevada. Amidst the dust of mining fortunes, this town thrived as a hub of gold mining activity.
Goldfield, Nevada, was founded in 1902 after gold was discovered in the area. The town quickly grew into one of the largest in Nevada, with a population peaking at around 20,000 during its heyday. Goldfield was established to support the booming mining industry in the region, particularly the gold mines.
The town boasted numerous businesses, including saloons, hotels, banks, and brothels, catering to the needs of miners and prospectors. It became known as the “Queen of the Tonopah Mining District” due to its wealth and prominence in the area.
However, like many mining towns, Goldfield’s fortunes declined after the initial boom. By the 1920s, the population had dwindled, and the town fell into decline. Today, Goldfield is a ghost of it’s former self, with remnants of its past glory still visible today, including historic buildings, mines, and artifacts.
Image courtesy of the University of Nevada, Reno, Special Collections. Nevada Ghost Towns and Historic Sites is in Goldfield, NV.
Yesterday, I headed up Heath Creek and got a quick snowshoe in to the upper gate. Only went about a mile up from Thrush Rd. However, it’s about 460′ of gain. It’s been so long since we’ve had this kind of snow. Forgot how much of a chug it would be with snowshoes on – ha! Good times.
Here’s a small section of the Wrightwood – Big Pines map depicting part of Heath Creek. Access this hike by taking the dirt road that departs south, climbing upslope from Thrush Rd. between Victorville Street and Heath Creek Rd.
Elevation Gain / Loss:
From the lower gate (just above Thrush Rd.) to upper gate = 460′. The elevation on Thrush Rd. at spot where you walk up the beginning of levee road is 5,840′. This gain takes place in approximately one mile along the levee road located on west side of Heath Creek. Elevation of upper gate is 6,300′.
If you have time, keep on going past the upper gate. Soon you’ll encounter some sawn log benches placed in a square configuration. Keep going further up along the stream bed on the old, steeply rutted jeep road which is in places barely a trace. It’s steeper going now than it was on the levee road between the two gates.
From upper gate to top end of old jeep road (abandoned) =400′. The top end of old road is where two canyons come together. There’s a forested canyon on the left side and small stream running between jagged walls on the right. The elevation here is 6,700′. Look for the little framework of limbs that have been lashed to some upright hand-hewn cedar poles.
Looking directly up Wright Mountain’s slide from the canyon bottom. This is the same slide you can view toward the south from the Wrightwood Post Office. Wright Mountain’s summit is at top of ridge on far left of photo at an elevation of 8,500′. Photo was taken at elevation of 6,300′ near upper gate.Today, finally dragged out the dusty snow shoes!Looking over my shoulder, this is all that’s being left behind.Heath Creek, looking down canyon. That’s the Mojave Desert on the distant skyline.Snow covered mountain mahogany, Heath Creek.Snow bent Great Basin Sagebrush about a mile up Heath Canyon from Thrush Rd.This little structure of lashed together branches and poles is up at the end of the hike. It’s up above the rocky stream bed at confluence of the two canyons.
9,399′ high Mt. Baden-Powell’s massif dominates the southwest skyline from Table Mountain.
Joanie and I got out for a great afternoon of snowshoeing up on Wrightwood’s Table Mountain about a week and a half ago. Since then, more storms have dropped even more of the precious powder on our local mountains. Whether you like to cross-country ski or snowshoe, it’s a fantastic time to be out amongst our high country peaks, canyons and forests!
Inset of the Trails of Wrightwood – Big Pines map. The area we went snowshoeing is depicted as Table Mountain (with campground symbol) at an elevation of 7,200′. The west end of Wrightwood appears in the lower right corner of image.
Table Mountain is 7,516′ high and super easy to get to from Wrightwood. Just drive. You’re only looking at four miles from our village center. Make sure to turn off to the right on Table Mountain Road when you arrive at the three way split in the roads at Big Pines. Table Mountain Campground is where we did our snowshoeing on a quiet Friday, where we seemed to have the place to ourselves. The wind had sculpted the snow into pristine dunes along the gently sloping ridge top that the extensive campground straddles.
Joanie seems to almost float atop the powder on the sunny slopes of Table Mountain!
All the campsites were, of course, hidden under the snowy mantle, with just the picnic tabletops presenting themselves as a bit of a depth gauge. Most of the time, snow depth was around 24″ and in places well over three feet. The windward sides of the mammoth white fir and Ponderosas were coated in sparkling icicles that fell like shards of glass in the wind gusts that came out of the southwest. Mt. Baden-Powell kept constant watch over us from across the great gulf of the East Fork of the San Gabriel River. The Mojave Desert off to the north was a mosaic of tans, yellow sands and the right-angled patchwork of green winter crops scattered here and there. It looked and felt warmer down there. And high up on Table Mountain, that day was to be one of cobalt blue skies, bright white snows, wind and evergreens.
A small wind-bent snowy pine and Chris have a little visit amongst Table Mountain’s frozen forest.
Distance and elevation gain / loss: Approximately one mile (one way) with 400′ of elevation gain.
Follow the gated dirt road that runs atop levee on north side of Heath Creek stream bed.
Hike begins on Thrush Rd, just east of the tee intersection with Victorville St. Walk up the dirt road just west of Heath Creek bridge. There’s a silver-colored pipe gate just a short distance above Thrush.
Looking toward the desert on the levee road. This spot is about half-way between the lower and upper pipe gates.
One of the major canyons dropping into Wrightwood’s Swarthout Valley is Heath Creek. It’s the canyon that begins as the large, conspicuous slide on Wright Mountain’s north side. The slide, dropping straight down from the summit is especially prominent from downtown Wrightwood. If you’re outside the post office or Mountain Hardware and looking southward, there’s a really good view of the slide, with Wright Mountain’s pine covered summit just to the left of it (elev. 8,505′). The canyon is named after Harry Heath who homesteaded the east end of the Swarthout Valley, near present day Pacific Crest Estates, back in 1886. Back then, Heath Ranch (circa 1900-1919) had a dairy, as well as boasting an orchard of apple and pear trees irrigated with water conveyed from a stream intake in the watercourse that today bears his name.
Outline of the former Heath Ranch. Purchased from Sumner Wright in 1902, Harry Heath received his deed for the land in 1910. You can see that some of Heath’s most suitable ranch land was in the area now known as Pacific Crest Estates. Oddly, his 160 acres do not extend to the watershed that bears his name. Map image courtesy of Wrightwood Historical Society.
Pat Krig, a long-time Wrightwood pioneer and historian, wrote down some notes about the Heath Ranch which she visited on horseback as a young girl. The Wrightwood Historical Society generously provided me a copy of her notes from 2006 which portrays what little is known of Harry Heath’s ranch. Unfortunately, there were no photos of either Heath or his ranch. One paragraph in Pat’s reminiscences that in particular stood out to me, was this: “A few of the gnarled apple trees still stand, bearing fruit and bringing memories of hot apple pies for tired travelers, and offers of a pitcher of fresh milk, thick cream for coffee, and butter to spread on warm, fragrant bread then slathered with pumpkin butter.” Pat wrote this back in 2006. Sadly, Pat passed away just this last year, taking with her memories of an earlier time in the mountains that we can only faintly imagine.
Last year’s dried flower stalks still draw your attention to clumps of buckwheat growing along Heath Creek.
Pearl Comfort Fisher, who wrote “The Mountaineers” back in 1972, provides a brief glimpse into a cowboy’s visit to the Heath Ranch back in 1907. The cowboy was Harvey Cheesman, hired to round up stray cattle from the nearby Lovejoy Springs Ranch. “So it happened that as I came over the divide from Lone Pine Canyon one cold February late afternoon I found the ranch or homestead of Harry Heath at the head of Sheep Creek. Upon knocking at the door I was met by a lady with a small baby in her arms. It was Mrs. Heath. She said, “‘My, am I glad to see some one. A mountain lion has been prowling around here for three nights and my husband is away working, and I am afraid the lion will get some of our pigs and chickens. “No lion showed up that night and I had to go on my way the next day.”
Today, it’s hard to imagine Wrightwood as wild and isolated as it must have been 112 years ago. The upper half of this hike will give you a taste of a quieter more forested Swarthout Valley.
Here’s a small section of the Wrightwood – Big Pines map depicting part of Heath Creek. Access this hike by taking the dirt road that departs south, climbing upslope from Thrush Rd. between Victorville Street and Heath Creek Rd.
This walk is a great one if you just have a little time, say less than an hour and you’d like to get some hill climbing in, too. You’re walking on a flood control levee road. The beginning of your trip is a bit exposed to the sun and completely devoid of trees, much of the landscape down in the wash to your left has a sterile, bleak look due to constant grading from county bulldozers. Not that great at first. . . Hang in there, the bleakness soon ends. Your route soon encounters black oaks, Jeffrey and Ponderosa pines on both sides of the levee road. An enticing flat makes its’ presence across the stream on your left. On your right is a gentle, expansive alluvial slope covered in a healthy pine forest. Mostly private, undeveloped land, this terrain gives you a sense of what Wrightwood must have been like in the 19th century. On a warm day, the air is fragrant with pine and amazingly quiet, save the occasional song bird or acorn woodpecker tapping high above the forest floor.
Trailhead for the Heath Creek hike is where Thrush crosses Heath Canyon. Thrush is the straight, east-west trending road just above (north) the “n” in Canyon. Notice that this U.S.G.S. topographic map section still shows Lone Pine Canyon Road crossing Heath Canyon, as it once did prior to the 1969 flood.
After a mile, you’ll encounter another silver painted pipe gate. This is your turnaround point. If you have the time, continue further up along the road to a set of four wooden benches set in a square configuration. Walk on past this gathering area, bearing left and staying with the canyon bottom. Follow a deeply eroded trace of a former jeep road. Essentially now a trail, continue on up the canyon for another 400′ feet of elevation to the trail’s end on a rocky berm above the stream bed. You will also see a little frame structure made from lashed together cedar trunks and limbs.
Here’s a Douglas Wallflower alongside the Upper Falls Trail, as seen this last Monday while hiking up the Big Santa Anita Canyon under cloudy skies. Our series of much-needed rain storms have brought back thick green grasses and the start to what’ll most likely be a colorful Spring of other wildflowers. Joanie and I hiked the two-mile Falling Sign Loop from Fern Lodge.
These Douglas Wallflowers (Erysimum capitatum) popped out at us just downstream from the double slot pools on the Upper Falls Trail. There’s also a nice grouping of wallflowers near the second bench up the road from Roberts’ Camp in San Olene Canyon.
Sturtevant Falls was tumbling down nicely. The scent of white sage peppered the cool air and the background surf-like sound of the stream followed us the whole way. We brought along an old shovel, cleaning off small slides here and there. Wild lilacs (buck brush) are still sending their mild lavender scent into the canyon breezes while the bright red orange of Indian paintbrush pokes up from the damp earth near Hoegee’s Drop-Off. And overarching along most of the route, the Laurel bay blossoms still cling to the dark green canopies. Look for the tender dark reddish purple leaves of the canyon big-leaf maples as their foliage begins to fill back in for a new season. Even the white alders are pushing out a myriad of their bright green leaflets, replacing that smokey look of dormancy with new life.
View looking east up into the East Fork of Big Santa Anita Canyon from Gabrielino Trail. Note the Toyon in the foreground, still hanging onto some of its’ red berries. That’s Rankin and Monrovia peaks in the most distant background. Clamshell Peak is barely captured on the right hand side of photo.
This turquoise colored fence lizard (Sceloporus occidentalis) was seen out in the warmth of early Spring at Tin Can Point. Tin Can Point is just up from Fern Lodge Junction on the Gabrielino Trail. It’s the first switchback you’d encounter after the trail passes through the canyon live oak forest and then enters the chaparral, just a few minutes up from the trail junction.
A beautiful fence lizard basks in the gentle warmth of early Spring at Tin Can Point. See inset of the Chantry Flat – Mt. Wilson Trails map, below, to see where this point is. As of this writing, a cold wet pacific storm is dropping nearly six days of chilly rain and snow in much of the San Gabriel mountains. Big Santa Anita Canyon dam has received over 5 1/2″ of rain in the last week. Something I just learned recently about these Western Fence lizards is that their populations have the effect of reducing the incidence of Lyme’s disease in the ticks that live in the chaparral, such as found covering much of the slopes of the Big Santa Anita Canyon! Apparently, a protein in the lizard’s blood kills the bacterium in the tick’s gut, which is good news for hikers and even their dogs during the spring and autumn months.
Like most reptiles, Western Fence lizards hibernate, at least for a little while each winter throughout their habitats which are wide-spread throughout California. As for food, these lizards eat spiders and various insects such as mosquitos, beetles and grasshoppers. The females lay several small clutches of eggs (3-17) in the spring, the young emerging in the summer.
Detail of Gabrielino Trail section, Chantry Flat – Mt. Wilson Trails map.
On your next hike out from Chantry Flats, watch for for lizards flitting about on the trails and sunning themselves on the myriad stretches of rock. As for the various types of reptiles to be found in the Big Santa Anita, Western Fence lizards are abundant and deserve a place in the sun!
