Shell ID and age

[29ford]

Hello everyone

I need help IDing these shells and more importantly the age. I have had these for 25-26 years, I got them when I worked offshore the Gaviota coast California about 7 miles and they came from about 3-4 thousand feet deep into the formation (maybe deeper, I cant remember its been so long ). They have to be millions of years old, the water depth there is 1000 feet and like I mentioned earlier they come up from 3-4 thousand feet deep into the formation.,

Thank you

[Ludwigia]

Am I understanding you correctly in that you are saying that you dug down 3-4 thousand feet already under 1000 feet of water and extracted these shells? Were you drilling boreholes? What is the name of the Formation?

[Troodon]

Neat lots of oil and gas drilling off of Santa Barbara.  So these came from the spoils of the drilling?

[29ford]

Hello, yes I was working on a offshore drilling platform, 7 miles off the coast of Gaviota California, just North of Santa Barbara. The rig is in 1000 feet of water and we were drilling oil wells, I was working the mud pits  and all of a sudden thousands of these small shells came across the shaker screens. The shakers separate the unwanted items from the drilling fluid, I worked there for a couple years and that was the only time I say that happen.

I know nothing about what the formation is called, maybe the Santa Barbara or Santa Ynez formations ? Ive seen articles about fossils above ground that were millions of years old but nothing like what I have being 7 miles offshore and 3-4 thousand feet deep maybe deeper, I cant remember  

[DPS Ammonite]

You need to photograph each fossil separately and they need to be clearer. A malacologist, might recognize these as being in the same genera as modern Pacific shells.

 

@Boesse
 

A quick search suggests that the rocks below the Channel are Cretaceous and newer. The fossils look Cretaceous and newer. 

 

https://pubs.usgs.gov/pp/0679/report.pdf

[Crusty_Crab]

These look consistent with what I have found in the Santa Barbara Formation. Most references I have found refer to the Santa Barbara Formation as Pleistocene, but the reference I will point you to below suggests Plio-Pleistocene. Many of the species found at that formation are currently still extant in California, so I don't believe you can date them based on faunal composition alone. I can't tell you if they are recent, sub-recent or belong to the Pleistocene Santa Barbara Formation. The marine gastropods here and in the Santa Barbara Formation are highly diverse, and new species are continually being described. You would surely need an expert malacologist to get an informed opinion. There are some very knowledgeable people at the Pacific Conchological Club that would be able to provide an ID if you are interested: https://www.pacific-conch-club.org/index.htm. That being said, this is an excellent resource to help you get started. It is an illustrated guide to the gastropods that are more commonly found in the Santa Barbara Formation: https://www.pacific-conch-club.org/index_files/Las Conchas 37-5.pdf

[29ford]

Some very good read there guys, I tried to contact that club last night but when I click on Contact Us it doesnt do anything. There were some shells in that article that were very similar. I really hope someone from the club chimes in. I will try to post some better pictures.   Thank you guys I really do appreciate your help

Edited June 22, 2022 by 29ford

[DPS Ammonite]

See this Wikipedia article that says that the oil in the Carpinteria field occurs in the Pliocene Pico Formation which is about 3,800 below the ground surface.

 

https://en.m.wikipedia.org/wiki/Carpinteria_Offshore_Oil_Field

 

So the shells may be Pliocene in age.

 

 

[29ford]

That is awesome work DPS, that puts them at 2.4-2.5 million years old. I will have to read all the articles tonight 

[Crusty_Crab]

I have to express my skepticism that this is from the Pliocene Pico or anything in the millions of years old. You mentioned that this was recovered in drilling muds. Drilling muds could have been generated in the overlying strata. You can't pinpoint them to a single origin. The preservation and your finds are inconsistent with Pico Formation fossils that I have. To get to the hydrocarbon producing units, you'd have to drill through more recent sediments that are more recent or sub-recent. The City of Isla Vista commissioned an Environmental Impact Report that had included a detailed geology section. The geologists that had logged those borings noted that the Pliocene Sisquoc Formation, which is composed of soft diatomaceous mudstone, was below the Pleistocene marine terraces (equivalent to the Santa Barbara Formation. The Santa Barbara Formation is actually an informal name).  The link for the EIR is no longer maintained, but this is what is left: http://dcss.countyofsb.org/ceo/asset.c/1916. My personal experience with the Pico Formation is that they are well sorted, tan colored sandstones. Since the drilling muds incorporate sediments from all overlying strata, you can't assume they originate from any formation. If you had a boring log that documented the layers by a geologist, and recovered the fossils from a core, that would be different. In that case, a boring log would go a long way to prove where they originated.  

[Coco]

Hi,

 

On the 1st photo, the 3rd shell looks very much like the recent genus Ocenebra. Here is my collection of East Atlantic Ocenebra erinacea (French coasts).

 

@MikeR

 

Coco

[29ford]

Yes, look very much like the 2 lower left shells. What age would you put them at ?  Thank you

[Coco]

All the specimens are recent, and the same species for all.

 

Coco

[FranzBernhard]

On 6/22/2022 at 6:52 PM, 29ford said:

they came from about 3-4 thousand feet deep into the formation (maybe deeper, I cant remember its been so long )

 

On 6/22/2022 at 8:18 PM, 29ford said:

and all of a sudden thousands of these small shells came across the shaker screens. The shakers separate the unwanted items from the drilling fluid, I worked there for a couple years and that was the only time I say that happen.

Seems to be stratigraphically somewhat constraint.

Franz Bernhard

[29ford]

Hi Franz, what info do you need ?Platform Heritage is in 1000 feet of water, 7 miles off Gaviota Pier, 10 miles North of Santa Barbara, California.  The shells came up from 3-4 thousand feet in the formation.

[29ford]

Franz, What I am trying to find out is the formations and age of these, I know nothing about formations and dates or fossils. That is why I am here, There would be no way for me to get into the drilling logs, it would solve the mystery if I could. If you can help please do.

[FranzBernhard]

12 minutes ago, 29ford said:

Platform Heritage is in 1000 feet of water, 7 miles off Gaviota Pier, 10 miles North of Santa Barbara, California.  The shells came up from 3-4 thousand feet in the formation.

I will not dig into this area , but with this specific information, other, more knowledgeable members could do. Thanks for the details!

 

2 minutes ago, 29ford said:

If you can help please do.

Sorry, I can´t. Its a long time since drilling, so something may have been published about the offshore geology of this area, based on all the drillings done?

 

On 6/23/2022 at 1:32 AM, Crusty_Crab said:

Since the drilling muds incorporate sediments from all overlying strata, you can't assume they originate from any formation.

They appeared only once during many years of drilling, thousands of them!

 

Franz Bernhard

Edited June 24, 2022 by FranzBernhard

[DPS Ammonite]

 

Contact Richard Squires, a retired a Cal State University Northridge professor with extensive experience with California gastropods.

 

Edited June 24, 2022 by DPS Ammonite

[29ford]

when a new hole is drilled, the drilling fluid (called MUD) creates a wall cake to keep the formation out. When you get to a pre planned depth a steel liner in put in place, then you drill another leg with the drilling fluid (MUD)  lining the freshly drilled hole, the MUD cools the drill bit, lines the hole and brings the cuttings to the top. The MUD is then cleaned and pumped back into the hole, a continuous cycle. I worked the mud pits for years and that was the only time that happened, the shells suddenly appeared, they came across the shakers for a couple minutes then stopped. I grabbed a couple and that is what is in the pictures 

[29ford]

Thank you very much DPS, I will do that for sure. Have a great weekend

[DPS Ammonite]

Here is an article by Squires on Pico Fm. fossils. See if any look like yours.

 

https://scvhistory.com/scvhistory/files/squires2012/squires2012.html#p=16

 

 

[29ford]

Thank you, I will read. I just sent Richard a email and the pictures of the shells, I will let you know his reply

[Boesse]

My only concern is that the smallest one resembles an oyster drill, Urosalpinx cinerea, which is a 20th century introduction to the Pacific coast from the Atlantic. I might be wrong but it looks very similar.

[29ford]

Hello everyone

Yesterday I wrote Richard Squires from the  California University of Northridge at the advise from DPS and Richard did reply last night. He says it is his opinion that the smaller one being Ocenebra Interfossa, the middle sized one being Nassarius Mendicus and the largest being Antiplanes and Richard believes they are from the Late Pleistocene age. I also have the Santa Barbara Museum of Natural History looking into these, I should hear something from them next week. We are getting there.

[Boesse]

Richard would know far better than I would!