“The desert holds the memory of ocean tides”
Marsha and
I have always felt most at home either in dry, barren areas of land, or on
sandy beaches. That is why we mostly
vacationed in either the deserts of the American southwest or at the ocean
shores of North Carolina. And now we
have moved to Rancho Viejo, a community located several miles outside the city
limits of Santa Fe New Mexico, near the Galisteo Basin – one of the most
interesting geological, archaeological, and historical regions in North
America. Absolutely the right place for
us, but still there is that “either or” feeling.
Then at a
Book Art exhibit of Santa Fe Book Arts Group I read the poem “Once There Was an
Ocean Here” by Liz Paterson with the phrase, “The desert holds the memory of ocean tides,”
which brought me back to an Elderhostel (now called Road Scholar) educational trip to the Chihuahuan
Desert in Big Bend National Park that we went on in 1998.
One of our
instructors was a self-trained paleontologist named K – a surveyor by training
and vocation who had come to the area a decade earlier on a job assignment; became
obsessed with the paleontological possibilities of, what he would say is, “one
of the most complete pictures of a prehistoric ecosystem known anywhere on
earth,” and with the solitariness to pursue that fixation; and just never left.
The desert can do that to you.
We went out
on a dig for fossils with K who, like the avaricious gold seekers in the movie Treasure of Sierra Madre, was unwilling to let us rank amateurs actually lay hands on
any of the prehistoric leftovers that we came across. (The desert can do that
to you also.) Later on we visited his
retired yellow school bus “museum” jam-packed with osteo-relics for a hands-off
tour.
The fossil
record at Big Bend includes artifacts ranging in time from the Age of Reptiles
to the Age of Mammals, beginning about 100 million years ago when a huge sea
covered most of what is today the midwestern part of the United States. Many of these marine fossils can be found in
the remaining sea layers of limestone known as the Boquillas Formation, including
a 30-foot long sea-dwelling reptile known as Mosasaurus.
Some
quick
Internet searching revealed that during what is called the Pennsylvanian
Period
(323 to 299 million years ago) almost sixty percent of New Mexico was
covered
with shallow seas – including Santa Fe. (Also known as Upper
Carboniferous or Late Carboniferous, Pennsylvanian is named after the
U.S. state of Pennsylvania where the coal-productive beds formed during
this age are widespread.)
Subsequent
mountain-building activity pushed up the basins and strata that had been left
behind by the sea to form what is now called the Sangre de Cristo Mountains –
about fifteen miles to the northeast of our address as the raven flies, and
clearly visible from the walking trail at the end of our street. On the Santa Fe side of the “Sangres” you can
discern at least one cycle of sea level change, starting with beds of marine limestone
deposited in a clear, well aerated, sub-tidal environment, as well as
interbedded limestone, and mudstone – plus ripple marks on sandstone that
document the shifting tides of the sea.
Small numbers of Pennsylvanian Trilobites (a fossil group of extinct
marine arthropods) have been found in the Santa Fe area.
This
southernmost sub-range of the Rocky Mountains – named “Blood of Christ” in 1719
by the Spanish explorer Antonio Valverde y Cosio after being impressed by the
reddish hue of the snowy peaks at sunrise, also known as alpenglow – is home to
the Santa Fe Ski Basin (10,350 ft. – 12,075ft) whose snow (albeit mostly
manmade in recent years) can be either an autumn harbinger of the winter to
come or a spring reminder of the winter past.
Geologically
these peaks are composed of granite that has been “metamorphosed” (i.e. altered
by heat and pressure). Granites are
formed by molten magma that never quite makes it to the surface and cools
slowly to form solid rock. After
cooling, some of these stones are subject to additional intense heart and
pressure, which causes some of the minerals within them to line up in very
faint bands on the surface of the rock.
Called “gneiss” (“nice”) many of these stones can be found along nearby
U.S. Route 285 and, according to the book “Windmills and Dreams,” are estimated
to be more than one billion (with a “B”) years old.
If we take
the same the trail in another direction Marsha and I can see the Jemez
Mountains to our west – the cause of our dazzling daily sunsets. The highest point in the range is Chicoma
Mountain at an elevation of 11,561 feet.
The Jemez (or Tsąmpiye'ip'įn in Native American Towa) are made up of
several volcanoes and the volcanic fields that erupted from them. The last explosion was about one and a half
million years ago and spewed out 150 times the volume of ash as the 1980 Mt.
St. Helens discharge. This eruption also
caused the formation of Valle Caldera (one of the largest caldera features on
the planet) about 60 raven flight miles to the northwest of Santa Fe.
Between our
neighboring “census-designated place” (CDP) of Eldorado and the Jemez Mountains
lies the Rio Grande Rift. A rift is a
long thin zone of the earth’s crust where, due to plate tectonics, the
continent is attempting to pull apart.
The Rio Grande Rift extends from southern Colorado to just over the
border with Old Mexico (a designation I never would have felt the need to use
in our prior home of Connecticut). The
Rio Grande fissure is considered a “failed rift” because instead of seawater
like the “successful rift” that formed the Red Sea, it merely contains sediment
and several layers of down-dropped rocks.
The other
major prominence that creates the visual border of the high desert land around
our community are the Sandia Mountains (Southern Tiwa name posu gai hoo-oo,
"where water slides down arroyo") located on the eastern side of the
city of Albuquerque, about thirty-five raven or car miles to the south. Sandia means watermelon in Spanish, which is
popularly believed to refer to either the reddish color of the mountains at
sunset, or to the profile of the mountains with a zone of green conifers along
the top suggesting the rind of the large melon-like fruit. Another theory is that in 1540 the Spanish named
the Indian pueblo near the range “Sandia” because they mistakenly thought the
squash grown there were watermelons.
They then ascribed that same name to the mountains. Native Americans also called it “Bien Mur” or
“big mountain.”
The Sandias
measure about seventeen miles long (north-south) and vary in width from four to
eight miles with a height of 9,700 feet to 10,400 feet. Today a 2.7 mile long Aerial Tramway ascends
4,000 feet in fifteen minutes to the top where hikers can explore the many trails. The High Finance Restaurant, formerly at the
peak, is currently (2017) closed “as part of a larger plan to replace the aging
structure with a new building and new concept,” according to the Albuquerque
Journal.
Geologically
the west side of Sandia contains Precambrian aged rocks in the lower part of
the mountain and (most curiously) a thin series of layered limestone that began
as mud at the bottom of a warm shallow sea.
In the
foreground between Ranch Viejo and these three mountains are a number of
smaller ranges, and a “cuesta”. Cerro Pelon
(“Bald Rock”) is a formation with one steep side and one sloping side that was
created by the abrupt intrusion of molten rock through two different
sedimentary rock formations. To the
cuesta’s right the Manzano Mountains, with a Precambrian configuration like the
Sangres, form the eastern backdrop for the Rio Grande River near the town of
Belen.
The San
Pedro Mountains and the Ortiz Mountains are similar in geology to the Sangre de
Cristo but much younger having been formed about 30 million years ago. The Ortiz were the site of the first American
Gold Rush in 1820, leaving a line of talus (debris rock) from the mining
operations. 350,000 ounces of the
precious metal have been removed to date.
Los Cerrillos (the “Little Hills”) are made up of cooled magma and
turquoise, which has been mined by the Native Americans for over a thousand
years. European mining claims later led
to a series of owners, including New York City’s Tiffany and Company. In the 1880s the market value of turquoise
was comparable to that of gold.
(Herculano Montoya at the Tiffany mine (1937). Palace of the Governors Photo Archives.)
While these pinnacles are visible all of the time, our perception of them is sometimes less than crystal clear. Early morning haze, low-hanging clouds, smoke from fires in California, distant falling precipitation, or blowing dust from high winds in March and April sometimes veils, or totally hides, each layer of mountain behind its own ghostly curtain of translucent (or opaque) mist. And, when you are at ground level, they are not always cleanly delineated from each other, as they would be on a map. Especially since, as we traverse the area, we keep coming at them from different angles. As a result Marsha and I cannot yet definitively identify all of the foreground summits. So we have to keep exploring. Which, in my mind at least, just makes our interesting geology even more interesting.
Even before
we moved to the Southwest Marsha and I knew we would deeply miss the sights and
sounds of the white sands and crashing waves of what Carolinians like to call
the Crystal Coast – as well as that sense of calm and belonging that we got
from wading in the waters of the Atlantic, and feeling the sea salt drying on
our tan sunbaked skin.
So it is
comforting now to know that we don’t really have to fly 1,800 miles east to
recapture that feeling. Instead, all
that we have to do is dig down about 300 million geological years beneath our
feet. No more “either or.”
The desert – and mountains – can do that to you.
“A census-designated place (CDP) is aconcentration of population defined by the United States Census Bureau forstatistical purposes only. CDPs have been used in each decennial census since 1980 as the counterparts of incorporated places, such as self-governing cities, towns, and villages, for the purposes of gathering and correlating statistical data. The boundaries of a CDP have no legal status.” (Wikipedia.com)
