A Geology Field Trip to the Local Mountains and Desert (yes, GEOLOGY)

I am taking a Physical Geology course at Mesa College, as a pleasant diversion from the life sciences. San Diego County is chock full of fascinating rocks and minerals and interesting land forms. More than I ever imagined!

On March 19th, we took a day-long field trip to the Laguna Mountains, and then the local desert. Terri Groth (friend and neighbor) accompanied me. About 13 people were on the adventure, including fellow classmates and the instructor, Don Barrie.

The photos below are from Canyon sin Nombre ("canyon without a name"), not far from Indian Gorge where we camped the weekend before.

This canyon was full of fascinating geological formations and types of rocks, including igneous, sedimentary and metamorphic - a little of everything we are learning about in the class at the moment.

Varied landscape near the entrance to Canyon sin Nombre. Much of the dark brown rocks are schist, a metamorphic rock.

More of the unusual swirls and strange rock patterns.

A big dike of light-colored igneous rock filling an ancient crack.

Contrast between the darker (what I believe is schist) and the felsic, light-colored igneous rock of the dike.

Some really nice gneiss (pronounced "nice"), another metamorphic rock, the result of ultra-high temperatures and pressures deep in the Earth.

Amphibolite, another metamorphic rock. 

Schist, a metamorphic rock with course grains, and foliation (a "layered" look), the result of intense pressures.

Folding in sedimentary rocks in the Olla Formation.

Found: One Small, Lethargic Bat

We discovered a lone bat on the ground today, under the oaks near Mountain Meadow Road. It is quite tiny (under 2 inches in body length, excluding the tail) and seemed lethargic (no surprise, as it would normally be hidden in a roost at this time of the day). I photographed it and then we relocated it to the interior of a large manzanita bush for the time being. I checked on it about a half hour ago, and it was hanging upside down in a "healthy-looking" posture (for a bat) in the manzanita. We were highly cautious in its handling in case it was rabid.

Perhaps California Myotis or Long-legged Myotis? Any bat experts are welcome to help with identification!

A Nearby Trip to Chariot Canyon

Chariot Canyon is just south of Banner, at the base of the Banner Grade. It really requires four-wheel-drive to negotiate it without too much stress and anxiety. I took the truck down there in mid-August and found primarily small species of insects on the just-blooming Baccharis bushes.

An assassin bug, with TINY prey! It was lurking on Baccharis, awaiting victims visiting the little flowers.

Close-up, showing the tiny little meal. Its wing is quite iridescent!

An ambush bug, another predator lurking in the flowering Baccharis. I believe that this is Phymata pacifica. It blends in beautifully with its almost "disruptive" coloration.

A view of Chariot Canyon, south of the Golden Chariot Mine. It is an idyllic spot.

End of the line for the day. Someone had put a couple of ineffectual little straps around this big oak that had fallen in the road, presumably in an attempt to move it. It took about a ten point turn to turn around in these tight quarters in the truck, but it worked out. Will have to go back later in the season to see how things have changed.

The Aftermath of the Chariot Fire in the Laguna Mountains

I took a drive along the Sunrise Highway today, to observe the damage from the Chariot Fire, which started on July 7. In general, most of the forest in the Laguna Mountain Recreation Area is still intact and unburned. The worst damage occurred on the northern edge of the forest, and in the chaparral to the east of Sunrise Highway.

Driving south on the Sunrise Highway, the first signs of the burn occur just after entering the Laguna Mountain Recreation Area. The burn was confined to the east side of the road at this point. The west side of the road was burned in the Pines Fire in 2002, so has had over ten years of recovery time.

The patchiness of the burn in the chaparral.

The beginnings of the pine forest. This is a view of the east side of Sunrise Highway, but the fire jumped the road in this area, slightly south of the previous photo's location. There was a lot of mist here from a mass of moisture that moved into the area today.

Partially burned pine.

The west side of the Sunrise Highway, north of the Al Bahr Shrine Camp.

The worst hit of the camps and retreats along this stretch. 

Al Bahr Shrine Camp. Green, unburned forest is visible in the background here.

Some of the damage at the Al Bahr Shrine Camp.

Just past the Al Bahr Shrine Camp (heading south) and across from the Foster Lodge, is the entrance to these campgrounds and hiking areas. As shown, there was no access, so I could not see how this spot fared in the fire. 

Just south of the Horse Heaven Campground, which is just south of the Laguna/El Prado Campgrounds shown in the previous photo, the fire ended, at least as far as what was visible from the Sunrise Highway.

Some typical forest south of the Horse Heaven Campground, green and alive!

Deer Bot Flies at Lake Morena

After reading Margarethe Brummermann's blog post yesterday about bot flies, I became intrigued by the fuzzy, bumblebee-mimic deer bot fly pictured in the post:

http://arizonabeetlesbugsbirdsandmore.blogspot.com/2013/04/it-always-pays-to-watch-competition.html

Then I consulted Lynn Monroe's new book: "Desert Insects and Kin of Southern California: A Photographic Survey and Natural History - Anza Borrego Desert State Park" and became convinced that these bot flies might not only exist in the region, but that they might be out and about at this time of year.

So after meeting Gary's son Ted at the Mexican border to see him off on his Pacific Crest Trail adventure, Gary and I decided to take a hike at Lake Morena, convenient and close by. I did not really expect perfect "hill top" conditions (hill-topping is the habit of some insects of congregating at a high point like the top of a hill or mountain and often establishing territories, in an attempt to intercept passing potential mates). Bot flies are known for this behavior, and amazingly, after a false alarm, in which I thought a smaller carpenter bee was a bot fly (!), we actually FOUND deer bot flies perched and periodically flying about at a high point in the chaparral overlooking the lake!

Cephenemyia jellisoni, a Deer Bot Fly. This specimen was captured at Lake Morena, southern San Diego County, on April 20, 2013. 

Dorsal view of Cephenemyia jellisoni, deer bot fly. Lake Morena, April 20, 2013.

These flies do not feed as adults, but after mating, females will deposit tiny larvae in the nasal cavities of Mule Deer. The maggots can reach as much as an inch in length, and will develop inside the respiratory passages of the deer.  Later the maggots will be sneezed out, to eventually pupate in the ground and emerge as an adult fly. Apparently this does little harm to the deer, despite its repulsiveness to humans.

The "hill top" at Lake Morena. Rich chaparral habitat. 

Lake Morena, San Diego County, California.