The Breath of Winter
December 07, 2010
I know it’s not nearly as impressive as what those of you back East are enjoying right now, but here in Northern New Mexico, it’s been getting down below freezing most nights for the past two or three weeks, and there have been light snows in the mountains from time to time. Ski Santa Fe is scheduled to open on December 10, admittedly with the assistance of the snow-makers – but that lets you know it’s cold up there.
I like all kinds of weather, but I’ll confess that, from a geological point of view, it’s a little disappointing to see the ground disappear under the snow. You get a notion to have a look a particular belt of outcrops, only to be thwarted by that unusual mineral called ice. The last few weekends have been dry and relatively warm, however, and I’ve been getting out for some nice walks on the Chamisa Trail and the lower parts of the Winsor Trail, all good hikes in almost any weather, and blessed with wonderful light on a sunny winter afternoon.
On our side of the mountains, Winsor Trail follow Tesuque Creek up nearly to Hyde Memorial State Park before it jogs off to the north and begins its climb up toward the Nordic Ski Area and Ski Santa Fe. The water is beginning to ice over and there are only a few places now where you can see the water burbling along its stony bed. One unexpected pleasure of a winter hike: those difficult stream crossings in the spring are a breeze in the winter:
Since the Winsor Trail basically crosses the entire Santa Fe Range from west to east, it gives the observant hiker a look at nearly all the fascinating rocks that crop out in the mountains. It also gives you a taste of several climatic zones and their associated flora and fauna, from dwarf cactus and spiky yucca on the south-facing slopes near Tesuque all the way to alpine tundra and twisted bristlecone pines on the flanks of Santa Fe Baldy. With some magnificent forests and meadows in between.
Most of my walks lately have been in the 8000 to 9000 foot elevation range, where the conifers are mixed in species and delight the eye with their variety.
A number of key geological transitions can be seen on a walk along Tesuque Creek once you get in the habit of looking. One of the most notable ones occurs just north of the junction of the Winsor Trail with the Chamisa Trail. From this junction, downstream and to the west, the ground is littered with fragments of a dark, glittery, very distinctive rock called amphibolite schist. But as you walk upstream from the junction, through a meadow and just past a mysterious old overgrown stone dam, you’ll notice that the path is now simply an orangy-pink:
You’ve crossed a fundamental boundary in the bedrock, one that separates a belt of strongly deformed and metamorphosed sediments with a heavy component of dark volcanic tuffs and lavas, from an equally deformed belt of very hard pink granite. Not far after this transition the trail is forced to leave the pleasant meadows along the creek and cut its way along the canyon walls:
Here you can get a good look at the granite, and see how it has been stretched by shearing forces deep in the Earth’s crust. This is revealed by strongly aligned streaks of dark mica called biotite.
These rocks are exceedingly ancient, perhaps as much as 1.7 billion years old, and they got their distinctive textures via crushing in the roots of long vanished range of mountains, perhaps 10 – 15 miles deep in the crust. The granite was originally injected as a molten mass of rock, but it, too, was caught up in shearing forces after it crystallized (losing much of its countertop potential into the bargain, I might add).
If you’re like me, you might gain some appreciation of the trouble geologists must go to, to mark these boundaries on their maps. There simply isn’t any one place where X marks the spot, and all those beautiful trees and wildflowers simply obscure the facts. On the other hand, there are beautiful trees and wildflowers to look at – and subtler autumnal and winter vistas at this time of year – so whether you’re a rockhound or not, be sure to make time for a walk while you’re visiting us here in Santa Fe.
Getting There: I’ve been accessing this part of the mountains via the Chamisa Trail, a very popular trail a short way from Santa Fe, just inside the Santa Fe National Forest border.
From the Inn on the Alameda, you turn north on Paseo de Peralta, and then turn right at the light at the intersection of Paseo with Bishops Lodge Road. A second right at the next light, which is Artist Road, or NM 475, puts you on your way. About six miles along 475 you’ll see the sign marking the boundary of the national forest, and very shortly thereafter some parking place both on the left and (for overflow) on the right side of the road.
The trail maintained by the Forest Service is the uppermost one, at the trailhead to the right of the parking area, and this is the way I recommend. There is a less formal path directly along the creek, much favored by dog-walkers. After a mile’s walk along the trail you’ll reach a saddle with a sign, and another mile north brings you to Tesuque Creek and the junction with the Winsor Trail. There are beautiful meadows along here where you might enjoy a thermos of something hot. If you head west, downstream, you’ll encounter outcroppings of metamorphic rocks, and if you head east, upstream, you’ll see the transitions I’ve written about above. An ambitious hike will bring you to the meadow at the junction with the Borrego Trail, where you will see boulders of yet another crystalline component of the Santa Fe Range. But that’s for another time.