Zephyr Posted January 23, 2011 Share Posted January 23, 2011 (edited) This is my last set of questions for the experts here (though so far my home run to hit ratio is not looking great). First I think that I've narrowed the range of the Temblor Seaway (formerly San Joaquin Sea) at the time, but not sure. The following two pics seem to agree. However I've seen others which show a more extensive seaway to the north at the time at the time than these show. Any thoughts? http://tinyurl.com/4qb8nuq http://tinyurl.com/496pf5w I've also read that the Sierras were about 170 miles east of their present location, yet I also read that the Temblor sea practically lapped at their base. That would be a long way inland and seems to disagree with the above maps of the width of the T sea at the time. Also everyone I've read says that the Temblor was a shallow sea (~ 200' with areas of deeper waters). However I've also read that the Santa Margarita Formation was laid down in deep waters to 3,000'. What am I missing here? Last, I've read that the temps during the Middle Miocene were on average 3-4C higher than today which puts it in the range of the curent warnings re: climate change. That seems pretty hot. And yet it was simultaneous with the Clarendonian Chronofauna. Thoughts? Thanks to all for your comments, especially piranha. This is a great site. Z Edited January 23, 2011 by Zephyray Link to comment Share on other sites More sharing options...
Fruitbat Posted January 24, 2011 Share Posted January 24, 2011 A couple of additional articles you might be interested in (if you don't already have them). Bowersox, J.R. (2004). Late Neogene Paleobathymetry, Relative Sea Leval, and Basin-Margin Subsidence, Northwest San Joaquin Basin, California. Search and Discovery Article #30029. Johnson, C.L. and S.A. Graham. Chapter 6. Middle Tertiary Stratigraphic Sequences of the San Joaquin Basin, California. In: Petroleum Systems and Geologic Assessment of Oil and Gas in the San Joaquin Basin Province, California. I gave the Bowersox article a quick once-over and it looks like it might be particularly interesting. -Joe Illigitimati non carborundum Fruitbat's PDF Library Link to comment Share on other sites More sharing options...
Zephyr Posted January 24, 2011 Author Share Posted January 24, 2011 A couple of additional articles you might be interested in (if you don't already have them). Once again thanks very much for these Fruitbat. Those do look relevant and interesting. I'm now off to do some reading etc. Thanks to all here for your helpful comments and suggestions. Best, Z Link to comment Share on other sites More sharing options...
siteseer Posted January 24, 2011 Share Posted January 24, 2011 After noticing that you had yet to receive a response (Fruitbat's post arrived as I wrote this), I decided to take a swing. I'm not a geologist (just took two courses in college) so I can answer only generally. Middle Miocene marine fossils have been found as far north and inland as present-day Palo Alto. The Stanford Linear Accelerator facility displays a cast of a Palaeoparadoxia skeleton found during excavation in the 60's. I don't know if that is evidence of a northern stretch of the Temblor Sea or if it marks the extent of a separate inland sea. Your maps are more in line with what I've seen in my own reading with some area not far north of Coalinga being the northern extent of the Temblor Sea (abundant Desmostylus teeth from Monocline Ridge, Temblor Formation, which is roughly the age of the Sharktooth Hill Bonebed - approx. 15.5 million years old) and some area not far west of Bakersfield being the westernmost extent. However, I have been shown fossil whale vertebrae said to be found during excavations for a golf course near Hollister (site and stratigraphy unknown) and I have a whale vertebra from the Panoche Hills area (site and stratigraphy unknown) indicating a seaway existed that far north and west probably in the Miocene as the seaway was in clear retreat farther west by the Late Pliocene. The Temblor was probably deeper in the Early Miocene (Saucesian/Arikareean) than later because some deepwater shark teeth (Oxynotus) have been found in the Pyramid Hill Sand that are not known from the STH Bonebed (Barstovian). The Santa Margarita ranges in age from about 9 to 5 million years old (Clarendonian) and I don't think it has been observed any farther inland than parts of San Luis Obispo County - certainly closer to the coast than Coalinga. The Mid-Miocene Climatic Optimum took place during the Barstovian. I think your quote of temps 3-4C higher than today refers to that time. This is my last set of questions for the experts here (though so far my home run to hit ratio is not looking great). First I think that I've narrowed the range of the Temblor Seaway (formerly San Joaquin Sea) at the time, but not sure. The following two pics seem to agree. However I've seen others which show a more extensive seaway to the north at the time at the time than these show. Any thoughts? http://tinyurl.com/4qb8nuq http://tinyurl.com/496pf5w I've also read that the Sierras were about 170 miles east of their present location, yet I also read that the Temblor sea practically lapped at their base. That would be a long way inland and seems to disagree with the above maps of the width of the T sea at the time. Also everyone I've read says that the Temblor was a shallow sea (~ 200' with areas of deeper waters). However I've also read that the Santa Margarita Formation was laid down in deep waters to 3,000'. What am I missing here? Last, I've read that the temps during the Middle Miocene were on average 3-4C higher than today which puts it in the range of the curent warnings re: climate change. That seems pretty hot. And yet it was simultaneous with the Clarendonian Chronofauna. Thoughts? Thanks to all for your comments, especially piranha. This is a great site. Z Link to comment Share on other sites More sharing options...
Zephyr Posted January 24, 2011 Author Share Posted January 24, 2011 After noticing that you had yet to receive a response (Fruitbat's post arrived as I wrote this), I decided to take a swing. Great comments siteseer. I am going to look up the exact time reference for the Palaeoparadoxia you mention. I don't believe that would be the Temblor seaway but a separate incursion. But I could be wrong. I have maps that are pretty much all over the place. Though Hall's are the most recent. But Palo Alto is already pretty close to the Pacific and the San Francisco Bay so it wouldn't be unexpected to find something there. The Temblor would have connected to the pacific. It's just that inland the depth was much reduced, which, besides the already high temps, also helped to make it warmer. I'm thinking that my question about the 3,000' depths of the Santa Margarita Formation refer to areas along the outer coast. The Santa Margarita ranges in age from about 9 to 5 million years old (Clarendonian) and I don't think it has been observed any farther inland than parts of San Luis Obispo County - certainly closer to the coast than Coalinga. Good call. The Santa Lucia range, which include SLO county were islands back then. Again thanks everyone. I've now got to do some of Fruitbat's assigned reading. :-) Link to comment Share on other sites More sharing options...
Recommended Posts