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Puerto Penasco Weekend Trip..


safossils

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We took a trip to Puerto Penasco over the weekend. As a lot of you know, there's nothin' better then a beach with fossils. I have no idea what age these are, probably late Tertiary. They are overlain by what appears to be volcanic rocks related to the Quaternary Pinacate lava flows. I included a few picts of modern bones on the beach that I thought were interesting as well as some other photos. We alway have a good time there, and it's only a four hour drive from Tucson.

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rockypointbivalve308.jpgrockypointechinoid108.jpg

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rockypointbivalve208.jpg

rockypoingastropod108.jpg

rockypointbivalve108.jpg

birdamongtherocks.jpg

skullonthebeach.jpg

fishvert.jpg

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Great photos...I feel like I'm in the surf. Thanks for sharing.

My wife and I have driven down to Puerto Penasco twice. It's been a decade since the last visit so things have probably changed a lot. Last visit the place was halfway between a quaint seaside town and condo city.

It's an interesting geologic area. It's almost all Quartenary with a bit of Pleistocene here and there. The rocks at the main beach area are described in the literature as 35 to 45 thousand years b.p. Over the last couple hundred thousand years the shoreline has changed a lot with sea levels rising and falling in cycles with advance and retreats of ice in northern latitudes.

I don't remember specifics but there are also fossils here and there along that long barren stretch between the border and the seaside. If you poke around there is evidence of earlier shore lines. Probably mostly Quartenary but also some Pleistocene . We found mollusca but no other phyla like crustaceans or vertebrates.

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Any ideas about the source of the patterns in the 3rd image? I assume they're impressions of some plant.

Besides fossils,

I collect roadcuts,

Stream beds,

Winter beaches:

Places of pilgrimage.

Jasper Burns, Fossil Dreams

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Guest N.AL.hunter

Yeh, the third pic is of the bottom of a sand-dollar. They have that pattern on them even now.

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Great photos...I feel like I'm in the surf. Thanks for sharing.

My wife and I have driven down to Puerto Penasco twice. It's been a decade since the last visit so things have probably changed a lot. Last visit the place was halfway between a quaint seaside town and condo city.

It's an interesting geologic area. It's almost all Quartenary with a bit of Pleistocene here and there. The rocks at the main beach area are described in the literature as 35 to 45 thousand years b.p. Over the last couple hundred thousand years the shoreline has changed a lot with sea levels rising and falling in cycles with advance and retreats of ice in northern latitudes.

I don't remember specifics but there are also fossils here and there along that long barren stretch between the border and the seaside. If you poke around there is evidence of earlier shore lines. Probably mostly Quartenary but also some Pleistocene . We found mollusca but no other phyla like crustaceans or vertebrates.

Thanks for the information, we'll have to check out some of the outcrops on the way down next time.

Walt

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looks like you had a great time

Looks like fun to me. Not many beaches in north Texas.

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safossils:

Your trip to Puerto Penasco brings back many fond memories of a trip that I took to Puerto Penasco back in 1983. I took a class in marine ecology (for fun, since I had gotten my degree 12 years earlier) at a local college and a group of students (of which I was the oldest) and 2 professors made a one week trip during the summer to Puerto Penasco to collect modern marine life from the tidal pools and tidal flats along the gulf coast for the biology department. We stayed at a marine research station that at that time was jointly maintained by University of Arizona and I believe Northern Arizona University. The leader of our trip was a geology professor that I had taken several geology classes under years before so we spend much of the trip to Puerto Penasco studying the igneous and metamorphic rocks of southern Arizona and Northwestern Mexico including Copper Canyon. Not much paleontology, though.

When I was in Puerto Penasco, there was probably no more than 5000 people living there and tourism was minimal. It seemed that there were 2 primary industries at that time: fishing/shrimping and ice production to pack the fish and shrimp in. The fishing industry was so critical that there were always a number of federale troops on guard at the docks with automatic rifles. Apparently, the area has greatly changed and tourism has become a big business, with condominiums and even an international airport I understand. It was a beautiful area and the people were cordial. I never got used to the Teddy Bear Cholla growing right down the beach, however.

The todal pools were extremely impressive to me, with all of the marine life present. We collected an extensive array of marine life, including 2 small octopi that I found. I was also fascinated by the variety of chitons found on the rocks and wandered along the shoreline to the rocky hills leading down to the beach. All of a sudden, I was in seventh heaven as I was seeing fossils in layers in the sandy rocks. I collected a number of fossils clams and snails, but I was especially fascinated by the presence of Encope californicus that were weathering out of the rocks in certain beds. After collecting 10 or 12 better echinoids, I prepared to return to the group when I spotted two body valves and a terminal valve of a chiton in a slab of rock that had accumulated as float at the base of the cliff. These were the best finds of my trip and the only definite chiton fossils that I have found. While we there, another student found a rock with several ophiuroids preserved that were donated to the college collection. I never found any there, however, although I did find some in California. The geology professor told me that this specific outcrop north of the research station was a Pleistocene beach remnant, although most of the sedimentary deposits in the area were Quaternary.

All in all, it was a fantastic trip, both biologially and paleontologically. We filled 20 to 25 30-gallon plastic containers with marine life that were preserved in good ole formalin solution for preservation. I have always wanted to make it back down to Puerto Penasco, but I have never had the opportunity. Obviously, I would not recognize it now with all of the growth and development.

Regards,

Mike

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  • 4 weeks later...

that looks like the coolest place to hunt! im sure you got some goodies! :D

"Turn the fear of the unknown into the excitment of possibility!"


We dont stop playing because we grow old, we grow old because we stop playing.

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Since I have no idea what the rules for collecting in Mexico are, I just let them be. I collect very little material anyway, I'm usually content with a photo. The pieces that I do collect usually end up in museum displays or other public places. I have a few pieces that I take to displays, but my personal collection pretty much sucks.

Best,

Walt

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