The Ditch - Headwaters

In the year of the American Revolution, before there were dams or modern roads to confuse one’s sense of geography, Fray Francisco Atanasio Domínguez visited the church at Santa Cruz as part of a general review of their missions by the Franciscans.

He noted the village was near a “river, which, although it arises in the aforesaid sierra from three not very large springs, is joined from very high up by three or four rivulets which feed it more water than it brings from it source, and therefore it is permanent.”

The sources are today called the Río Frijoles and Río Medio which join before the river enters Santa Cruz Lake, and the Río Quemado which joins soon after it escapes impoundment.

The Picuris-Pecos fault that Patrick Sutherland says occurred during the Laramide Orogeny when the Sangre de Cristo were being formed the last time defines their origins to the east. On its west side, the fault thrust Precambrian rocks of the Ortega Formation over existing Pennsylvanian strata to the east. Embudo granite exists to the west.

The Jicarilla Fault, which dips in the opposite direction, lies a few miles to the east. It also appeared in Laramide times and now separates the Pennsylvanian from the Precambrian quartzite of the Truchas Range.

The Frijoles arises before the Picuris-Pecos Fault and curls south and west through the widening Panchuela West.

The origins of Río Medio lie farther north and east in the watershed before the Río Grande and Pecos known as Trailrider’s Wall that runs from Truchas Peak to Pecos Baldy. From there it crosses both the Jicarilla and Picuris-Pecos faults.

Río Quemado begins east of the Picrus-Pecos fault, with the south fork coming from somewhere between Middle Truchas Peak and Truchas Peak. The north fork leaves a glacial cirque near North Truchas Peak and falls 100' at the Quemado Falls.

All the mountain rivers are accessible to hikers and fishermen who aren’t intimidated by Forest Service warnings that a trail is not only difficult but hard to locate.

For common folk, the last you see of the Frijoles is in a valley that lies some 75' below route 503. Settlers in Cundiyo have dug ditches from the curving river to water what look like flattened hay fields.

The Medio is less visible as it wanders along the edge of a privately owned meadow just north of the confluence with the Frijoles. Even fisherman can’t get through there.

Río Quemado is hidden by the settlement of Cordova and by scrub that’s grown along its banks, but, away from the road, flows there through a fairly broad valley.

This is as far north as I can follow the Santa Cruz, and it’s as far north as settlement had penetrated when Domínguez counted 125 families living in the village of Santa Cruz, 71 in Chimayó after the confluence, 52 in Quemado and 26 in Truchas just beyond.

Notes: Francisco Atansio Domínguez. Republished 1956 as The Missions of New Mexico, 1776, translated and edited by Eleanor B. Adams and Angélico Chávez.

Photographs:
1. Río Frijoles as it joins the Rio Medio, 14 February 2012.

2. Río Frijoles below 503 east of Cundiyo, 16 February 2012; the river is marked by the red willow; the differences between the near hills and the Sangre de Cristo may be marked by the differences in vegetation in back.

3. Río Medio just before its merger with the Río Frijoles along route 503, 14 February 2012.

4. Río Quemado at Cordova just off county road 83, 21 February 2012.

On Learning

My plunge into reading New Mexico geology has taken me back to my first weeks as an undergraduate at Michigan State when I realized there were a great many people in my classes who had attended much better public schools than I.

I recognized I either had to work harder to stay even or fall below my personal standard, which wasn’t particularly high, given that mediocre school system, but still high enough to refuse to accept failure.

I remember making the decision some Saturday when my room mates went off to the football game and I stayed behind to study. That day alone, when I first forsook the life of parties, I began developing an ability to teach myself.

It’s a helpful skill now when I read books or articles that claim to be aimed at both the beginning graduate student and the professional. They assume a level of knowledge, mainly about plate tectonics, but also volcanism, that I simply don’t have. It means constant on-line connections to find the definitions of words and concepts.

Fortunately, no one I’ve read so far expects a greater knowledge of chemistry or physics than I have. My high school science teachers were among my worst. Unlike botany, which has been so revolutionized by biochemistry that after some five years of reading about plants I still have difficulty with articles about photosynthesis that assume an understanding of concepts like feedback mechanisms and communication pathways, most of the geology I’ve read so far expects no more than a recognition of the symbols for elements, a minimal understanding of how compounds change, and the understanding of the technical definitions of words like reduction that have broader, general meanings.

This is probably because many senior geologists, those of my general generation, don’t know much more than they learned in high school. Once they specialized, they didn’t need to know more.

This shows most in their attempts to continue to use the basic concepts of Newtonian mechanics relating to the behavior of heat to explain the, to them, new phenomenon of plate tectonics. I don’t know if this was a valid assumption or not, but it was an understandable one given the conservative nature of both science and the human mind.

This brings me to the second thing I realized my first term in school, that I was more interested in interdisciplinary studies than specialized ones. MSU then had a required freshman course called American Thought and Language, which sought to meet the history, English and composition requirements in a single class that placed important writers in their cultural context.

I think I may have spent that long ago Saturday reading Roy Horton and Herbert Edwards’ Backgrounds of American Literary Thought, the first unassigned book I ever bought, trying to understand what my professor was saying about Puritanism. By chance it was the one he was using to prepare his lectures.

I found I wasn’t interested in knowing more and more about Emerson or the XYZ Affair, which is where a major in English or history inevitably leads. I wanted to know about the houses where readers of Emerson lived and the influence of the French more than I did transcendentalism or diplomatic history.

Such a pursuit, if it’s to be more than gadfly dilettantism, requires some discipline, as my graduate school professors never tired of telling us. More important it demanded that ability to plunge into reading something beyond one’s existing level of knowledge.

This brings me to the third thing I realized that first term in college, that no matter how much one learns, there’s always something beyond that’s unknown. Some are so taunted by that edge it drives them to push the frontiers of knowledge. It sends others with a strong desire for explanations into deep theological inquiries.

I realized one is either driven or tormented or one sets limits. I learned to recognize the point where the answers to my questions were pulling me into areas I wasn’t interested in pursuing, and simply accepted that such was the case and I could exist without knowing.

Deciding what to pursue and what to ignore is something we all do to get through the day. Someone once asked Penelope Lively, a novelist who delineated the undercurrents in human relations, how, once she was aware of such things, she could ever get through the mechanics of a family meal when a person simply must ask another to pass the butter.

Geologists must make those decisions when they write an article. They define the purpose, then exclude things that are extraneous. When Steven Whitman and Karl Karlstrom wrote about the formation of the North American continent, they realized their contribution was a series of drawings showing the progression through time. Indeed, one can learn a great deal by only looking at the pictures.

Their supporting evidence was drawn from the rocks themselves. They assumed you knew the rocks. I’m less interested in specific rocks than geologists or rock hounds, and so took their facts as facts not to be bothered with yet. I wanted to know why, not how to properly identify or date a specimen.

They took the Precambrian world as a given. They assumed you knew what that was or that it didn’t matter to understanding the phenomenon they were describing. As an historian, I was lost. If this part of New Mexico began as an island arc, I needed to know more about the ocean at that time, something they barely mention.

I went on line and innocently keyed in the search words Precambrian and ocean. I discovered some German heavy metal group called The Ocean had recorded an album called Precambrian. Interesting, but not what I wanted to know.

With some refinements in my Google search, I eventually found a chapter by Steve Kershaw on Precambrian oceans in his book, Oceanography. He was interested in why the earth didn’t freeze in its early years when the young sun wasn’t as hot as it would become, and so devoted a great deal of space to the Young Sun Paradox.

That’s indeed an interesting question, but not what I immediately needed to know. However, to cover his material for that hypothetical new graduate student, he did mention things I did want to know: when the oceans came into being, how deep they were, how much space they covered.

In the process he also suggested something I hadn’t thought about, how changes in the chemistry of sea water, as recorded by rocks, affected the development of islands like those that would become New Mexico.

The final thing I learned, not my freshman year, but when I actually became that hypothetical graduate student in American studies, is that no one ever tells you exactly what you want to know.

Whitmeyer, Karlstrom and Kershaw have all told me things I need to know, but they are writing for a general audience. It’s going to be up to me to figure out what it means for understanding the geological history of the place I live in the Rio Grande rift valley.

Fossils

Even when confronted with the rapid obsolescence of computers and cell phones and cameras, one can still lose sight of how much has changed in science since the men at Los Alamos set off their first test explosion.

Grade school is still the time we learn about the geologic past. Young boys are still infatuated with the Jurassic age of dinosaurs. For some reason, I got struck by the Pennsylvanian era of swamps and evergreens when coal was being formed.

Back in those days in the middle 1950's, the world began with the Precambrian. I never thought why, it was simply so. At that age, one didn’t consider the wonders of zero either or worry about negative numbers. One simply learned to count, one, two, three.

While I was reading Ted Galusha and John Blick’s article on Tertiary sediments in the Española basin, I suddenly realized why. When I was a child a principal way to date rocks was with fossils. There were no fossils before the Precambrian age. There was no life as we know it to produce fossils. The beginning of life was the beginning of rocks.

Oh, there was something called the Archaean to account for those things that were obviously below, but had no retrievable history. They simply existed after the big bang and solidification of the earth’s crust, but before time.

The problem with fossils is they often are dated by the strata in which they are found. In turn, they are used to date other strata in a closed, self-referencing system with few points of independent verification.

The whole time I was reading Galusha and Blick, all I really wanted to know was how old are the rocks Daniel Koning says lie under my house and how did they get there. Their answer was:

“The Tesuque Formation apparently was deposited through part of the Hemingfordian, Barstovian, and most, if not all, of Clarendonian (early Pliocene) time.”

To get anything more specific than late Miocene, I had to look up those fossil groups, which were filled with animals both strange (camels, rhinos, horses) and extinct (oreodonts), many of which migrated across the Bering land bridge.

At least, when you do go on-line for information, there are artists’ attempts to grapple with what those bones looked like when they were moving about. They don’t answer my questions about age, but they are diverting.

Dating techniques were beginning to change when I was a child. At Enrico Fermi’s University of Chicago, where so much preliminary research into the nature of matter and the predictable half lives of radioactive isotopes was done that lead to the bomb, Willard Libby was applying the same model to carbon to develop methods for using the carbon-14 isotope to date items that contained carbon.

By the time I was in college, his methods were being accepted, but they were only good for 62 million years. That’s the Tertiary Eocene. It could date a mastodon, but not a dinosaur. Still that was more than adequate for me. I was becoming an historian, not a zoologist or geologist.

Since I last paid attention, engineers have used all those technical skills that led to things like computers and satellites used by cell phones to develop other tools for probing the past. They send electromagnetic signals and interpret the resonances. They use the half-lives of other elements like potassium and argon. Their papers become tables of graphs and columns of numbers one has to take as true while looking for the scattered intelligible words in sentences like:

“Other east-west gravity profiles between latitudes 32^o and 38^o also show this asthenospheric diapir, which thus forms a ridge-like Moho unwarp approximately parallel to the surface trace of the rift.”

Thank God for Google and the ability to look up any word, to learn aesthenospheric refers to the mantle and Moho the boundary between the mantle and the crust, to learn something detectable exists deep in the earth below the rift valley that may account for all the geologic activity.

These tools which I have to take with the same faith I once took the word Precambrian are probing the time when the plates were colliding billions, not millions, of years ago. That really is astounding. The latest Geological Society of American time scale breaks the Archaean into four phases and has a created a new “dates unknown” period, the Hadean for older than 3.8 billion.