San Felipe and Baja Geologt

San Felipe, Baja, Mexico  

Tony Tellier “El Chinero”
One of a series

Folded Bedding


After a short hike from Ruben’s one can see mute testimony to the power and violence of the tectonic forces that sheared the Baja peninsula from the mainland of Mexico.

To find it, walk up the beach, north, past the huge glass-walled house on the bluff into the cove lined with pale-orange reduced-iron beds, then turn back towards town and look into the cliff face.  (The cobble beach further up the coast has many small buried clams.)

These twisted and bent beds were once flat!  But now you can see bands that are folded over themselves, several times, up to 135°.  Note how many major folds there are, at least three!  Most obvious is the thick light-gray bed, which is mirrored below by another thick, but somewhat darker, band.  However, above them are many thin light-and-dark alternating “lines” – fine-grained shales.  The light colored rocks to the right (i.e., south) are decomposing granites, stained by the iron and manganese oxides, leached out by the waters of the Sea of Cortez.  These are the rocks that are the core of Baja, the Sierras.

Convoluted Bedding

The sea floor spreading that pulled San Felipe away from Rocky Point – Cardón cacti (Pachycereus pringlei) are found ONLY in Baja AND along the coast of Sonora -- also squeezed these beds endwise, forcing them into loops just like pushing on a rug!  Terrestrial sediments were buried, eventually becoming shale and then the confining pressures allowed them to bend without breaking: this would not be possible at the surface of the Earth, where these rocks are brittle and would shatter.



Overturned & Folded Bedding
  District Kiki’s RV / Restaurant “El Marino”
  Address  North end of Avenida Golfo de California
  Hours  Daylight
  Ambiance Totally striking
  Cost     Free
  Photo Op A lot of shots
  Condition Wave-washed
  Significance Tectonism at its finest
  Time 30 minutes
  Workout Short hike w/ easy bouldering
  Conclusion Worth a trip, then a “Coco Loco”!
  www  N/A
  GPS Coords: Lat: N 31°02.179'
Lon: W 114°49.577'

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Folded Bedding