I really like Santa Fe, New Mexico. So once I obtained the chance to current a
lecture on the Colorado River for
Southwest Seminars,
we took a couple of additional days to discover extra of the realm. My colleague, Kirt Kempter invited us alongside to see first hand the outcomes of his pandemic mission,
making an in depth map of a maar volcano to the southwest of the
metropolis. These options kind when magma interacts with groundwater to create a steam explosion, forming a shallow despair after the explosion. The despair can turn into stuffed with scoria (cinders) and lava flows, and typically a lava lake, which upon subsequent erosion can go away the post-maar volcanics standing in excessive reduction. It is a troublesome factor for learners to know for the reason that maar formation creates a despair however the trendy function is a mountain (the infilling lavas are extra resistant than the encircling supplies)
Santa Fe’s historic Plaza is the place the western terminus of the
Santa Fe Trail
is situated. The wood construction seen within the middle of the Plaza right here hides an
obelisk and plinth that was erected in 1867 to commemorate the perpetuation of
the Union after the Civil Conflict. Nevertheless, one facet of the obelisk praised
“The heroes who’ve fallen within the varied battles with savage Indians
within the territory of New Mexico.” In 1974, the phrase “savage” was chiseled out by an unknown
particular person. On October 12, 2020, the obelisk was toppled and the town started a neighborhood dialog on the way forward for the
monument.
We at all times go to the small city of Chimayo the place we purchase our yr’s provide of crimson
and inexperienced chile powder. The Virgil Retailer proven right here had a For Sale in entrance of
it – oh the horror!
On the Santuario de Chimayo.
On a pleasant sunny day, Kirt took us southwest of the town to the Diablo
volcano, the place he has accomplished an in depth research of its historical past and mode of
formation. It is a view to the west trying downstream to Diablo Canyon, carved by the intermittent stream of Cañada Ancha.
Google Earth picture of the Santa Fe space. The town and the Sangre de Cristo
Mountains are on the appropriate. The Cerros del Rio volcanic area and Diablo volcano
are on the left. In all of my visits to Santa Fe I by no means explored to the
southwest of the town. I had been east, north, south and west and was at all times
curious in regards to the hills to the southwest of the town. I’ve additionally been intrigued for why Santa
Fe grew so removed from the Rio Grande and on a comparatively featureless alluvial plain on the foot of the
mountains. I at all times puzzled why the Camino Actual diverged from the course of the river to climb onto the alluvium (there was a pueblo village right here of some significance). Nonetheless, what existed between the town and river? I quickly discovered.
Shut-up of the Google Earth picture. The broad alluvial plain is carved into the
Tesuque Formation and overlying Ancha Formation. Word that the Diablo volcano is
partially bisected by Cañada Ancha – an enormous a part of this story that will likely be revealed under!
Starting our trek as much as the highest of the volcano, situated within the
Diablo Canyon Recreation Area. The situation is common with rock climbers who discover the columnar joints within the partitions of the gorge
inviting.
Alongside the way in which, volcanic bombs have been strewn over the bottom, documenting a
sub-aerial origin on this occasion.
A view to the west of the Lengua del Diablo (Tongue of the Satan). Word the ground of Cañada Ancha on the far left and the Jemez Mountain and caldera on the horizon. The colourful rocks within the ridge of Lengua del Diablo are composed of tephra deposits from the maar explosion (the greenish, decrease cliff shaped by
phreatomagmatic processes), capped with darkish basaltic lava, scoria and ash (photograph middle) that was erupted after the formation of the maar. Word the vertical dike throughout the phreatomagmatic deposit. This dike episode truly fed the flows on the uppermost a part of the cliff. Throughout the phreatomagmatic deposit a really massive blocks of the Tesuque Formation that have been additionally thrown outwards from the steam blast. One in all these massive, pink-colored clasts may be seen on the base of the inexperienced cliff and left of the dike (partially hidden by a small juniper tree. An incredible publicity!
A big dike (middle) intrudes via older scoria layers.
Complicated interaction of maar tephra (golden coloration) and post-maar scoria and dikes.
An in depth-up of the earlier photograph displaying the darkish basalt dikes intruding the older tephra (golden).
View to the west from the highest of the maar towards the Jemez Mountains and Chicoma Peak. Cañada Ancha is seen within the flooring of the valley.
Panoramic view with Kirt Kempter mentioning options.
One other view of the Lengua del Diablo. After spending a couple of hours trying on the inside options of the volcano, I grew to become interested by its eruptive setting. Kirt had defined that the age of the Cerros del Rio volcanic area is usually constrained between 2.7 and a pair of.4 Ma, straddling the time boundary between the Pliocene and Pleistocene. Kirt additional defined that the sequence of occasions went from preliminary phreatomagmatic eruptions that created a maar despair, which gave approach to scoria cone formation and subsequent fluid lava flows and the formation of a lava lake. At the back of my thoughts, I stored pondering, “Why are we so excessive above the encircling terrain? The reply after all, is that 2.5 million years in the past, prime of the maar was the ground of the valley and erosion of Diablo Canyon had not but commenced. Â
And boy was this evident as we went to the lip of Diablo Canyon! Throughout Diablo Canyon and Cañada Ancha is a indifferent portion of a lava lake basalt that after crammed the central maar. It has been separated from the foreground by incision of the stream. Thus, Diablo Canyon is roughly 2.5 Ma.
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Shut-up of the far-side mesa. Word the small rise on prime of the mesa – that is composed of rounded cobbles and sand from Cañada Ancha when it was flowing on prime of the lava lake. The stream had no concept that its course was on prime of the sting of lava lake deposits and because it incised downward its course was not deflected away – superposition in motion! How lucky that these remnant cobbles are left on the high-standing mesa for this interpretation.
Diablo Canyon from the highest trying southeast and upstream on the mattress of Cañada Ancha. Spectacular.
Kirt together with his canines trying throughout the highest of the maar volcano to the Sanger de Cristo Mountains.
Our group on the finish of the hike – Helen, Kirt and John. Thanks Kirt for an ideal day and a beautiful area journey! Kirt will quickly publish a paper on his work and I’ll add an addendum to this submit when it’s prepared.
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Shut-up of the far-side mesa. Word the small rise on prime of the mesa – that is composed of rounded cobbles and sand from Cañada Ancha when it was flowing on prime of the lava lake. The stream had no concept that its course was on prime of the sting of lava lake deposits and because it incised downward its course was not deflected away – superposition in motion! How lucky that these remnant cobbles are left on the high-standing mesa for this interpretation.
