by Robert Verish

March 2005 Trip to Barstow/Yermo Area - Stromatolite Locality - Image Gallery


Images of the Barstow Formation Stromatolites - as found "in-situ".

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Barstow/Yermo Area, California - Trip date: 2005 March 12
M-Recovery Field Report - field investigation - Update: Stromatolite Locality Revisited
This locality is only a few hundred meters south of I15 (towards Elephant Mountain) between the Yermo Cutoff and Calico exits... ...more info' to come later.

Algal Mat-like Growths - stomatolite-like features partly composed of agatized fossil remains in thinly-bedded muddy limestone (lacustrine sediments). Area is underlain by Barstow Formation sedimentary rock. Since these relict fossils features are in sedimentary rock, and since the agatized portions seem to have a biogenic origin, a better term for this chalcedony may be:

chert nodule

Posted 2005 March 15 | by Robert Verish


The "outcrop"
- | - with the fossils in bedded limestone as seen from the "old highway".


The "fossil" locality
- | - from on top of the outcrop, looking back towards the old highway and I15.


Another view of the outcrop
- | - a close-up of the east end of the outcrop where the "nodules" are located.

 


Another view of the outcrop
- | - a close-up of the east end of the outcrop where the "nodules" are located.


Another view of the outcrop
- | - a close-up of the east end of the outcrop where the "nodules" are located.


Another view of the outcrop
- | - a close-up of the east end of the outcrop where the "nodules" are located.

 


Another view of the outcrop
- | - a close-up of the east end of the outcrop where the "nodules" are located.


     

The following is a reprint of a
Tom Schweich web page
His field notes from the 2002 Field Trip -

Saturday, April 20, 2002

 
      This morning is beautiful: clear and cool, with a warm sun. Maybe it will warm up to 75-80 degrees today.
     

I asked Emmett Harder if he knew any of the Dorr family, but he did not.
      Bob told us about the upcoming field trip. After reviewing marker beds in Pleistocene Lake Manix that are time and topography, we will review marker beds in Miocene sediments of the Barstow formation. The specific marker beds we will review are:

  • Strontium/Borate Layer (SBH)
  • Brown platy limestone (BPL)
  • Massive stromatolite limestone (MSL)
     

David Miller reviewed his work in the Dove Spring Formation, which he studied while developing a protocol for monitoring off-highway vehicle use. The fluvial environment indicates a relatively wet environment, as discussed in Quade, et al., 1996 and Benson, et al., 2002 who concluded that Las Vegas and the Great Basin was cooler and wetter until 8-9 kybp. This was related to the younger Dryas cold event.
      At Field Trip Stop 1-1, we are looking at mid-Pleistocene Lake Manix. Here tufa was deposited by blue-green algae on alluvial fan deposits in clear water (Photo 4).
Full Size Image

Agriculture in the Central Mojave. Full Size Image Climax vegetation on Harvard Hill.

Other Articles: Interstate 15: 56798 Harvard Hill

Locations: Harvard Hill.  

We then moved to Field Trip Stop 1-2, where we saw the brown platy limestone (BPL), with agate or chalcedony, which is one marker bed in Miocene Barstow Basin. Took Photos 5 and 6. Plants are Creosote Bush, Burroweed, and Desert Holly.
Full Size Image US I-15 as seen from Harvard Hill.  

Locations: Harvard Hill.  

Photo 7 shows I-15 from Harvard Hill. Collected stromatolites with plant fossils.

      While we waited for low-slung car consolidation, Fred Budinger told us about the Calico Early Man Site and some recent work.
Full Size Image Field trip discussion of the Miocene Barstow Basin.

   

Field Trip Stop 1-3. Parked cars in wash, walked up the hill to the silicified algal limestone. These were hard dark reddish-brown rocks over a softer brown-tan clastic rock. According to Bob Reynolds, the algal mats preserved here are the deep water facies of the MSL. The stromatolites interfinger with the andesite zone, and silicified very rapidly. The silica came from nearby volcanic rocks and, therefore, the silicified algal mats cannot be termed “biogenic.”
      Field Trip Stop 1-4 was at the drill pad on the north side of the east end of Daggett Ridge. Top of ridge has stromatolites. Resistent steeply dipping arkosic sandstone. Pink tuff is younger than the Strontium – Borate Layer (SBH) and may be mappable to the Peach Springs Tuff(?) at the Pink Lady Mine.
Full Size Image

View of Mojave Valley from Dagget Ridge    

Field Trip Stop 1-5, does the pink tuff correlate to the pink ash at Outlet Center Drive?
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