Did oceanic trenches leave any fossil record?

[Hapchazzard]

I've been curious about this for a long time. Nowadays, we know that oceanic trenches aren't the desolate aquatic wastelands we thought them to be, and there are animals living down there. Considering their rather extreme geologic environment I'm wondering, if it is even possible,  whether they left any discernible fossil-bearing facies in the record at all? Or just discernible facies, period. A cursory search yielded no results for me.

 

As far as I can see, sedimentation rates would be low, and any newly-formed sedimentary rocks would just get subducted and destroyed very quickly (in geological time). The only mechanism I could imagine for their preservation would be if marine snow was deposited in big enough amounts to form limestone, and if said limestone was then accreted onto the neighboring plate, rather than subducted under it. Could something like this work? Is there any literature concerning this topic, at all?

[jpc]

I think subduction is the force of evil here.  

 

[Wrangellian]

I don't know about fossils but I know that bits of oceanic crust do sometimes get accreted onto a continent now and then, in subduction areas. The geologic map I have of BC shows some. You've got me wondering what is the deepest-water fossil-bearing rock known..

[ynot]

I heard somewhere that the Wheeler schale (House range, Utah) is an oceanic trench / subduction zone deposit.

 

Aside from the falling debris from the water column, there are always land slides to bury any critters living down at the bottom of an oceanic trench.

I would not expect limestone to be in that type of environment as it forms from shallow water lime secreting algae and animals.

 

As for the debris being "subducted", most of the surface accumulations on the seafloor are scraped onto the overlying continental margin and the underlying oceanic plate is what is usually pushed under. (The California coastal range and most of the southern half of Alaska are made up of the scrapings.)

[Oxytropidoceras]

Trench sediments can be uplifted and preserved by a process called "obduction." Typically, they have been tectonically kneaded and intermixed with pieces of oceanic crust, oceanic deposits, fragments of seamounts to form sedimentary mélanges that are part of accretionary wedges (complexes). Trenches deposits are intermixed within many ancient accretionary complexes like the accretionary complexes that comprise most of Japan, parts of New Zealand, Barbados, and the Shoo Fly Complex of California.

 

Some papers are:

 

An, W., Hu, X. and Garzanti, E., 2018. Discovery of Upper Cretaceous Neo-

Tethyan trench deposits in south Tibet (Luogangcuo Formation). Lithosphere,

 10(3), pp.446-459. Open access

https://pubs.geoscienceworld.org/gsa/lithosphere/article-abstract/529823/discovery-of-upper-cretaceous-neo-tethyan-trench

 

Hara, A., Kiminami, K., 1989. Ancient trench-fill and trench-slope basin deposits: 

an example from the Permian Nishiki Group, Southwest Japan. In: Taira, A., 

Masuda, F. (Eds.), Sedimentary Facies in the Active Plate Margin. TERRAPUB,

 Tokyo, pp. 557–575

https://www.terrapub.co.jp/e-library/taira/pdf/557.pdf

 

Ingersoll, R.V., 2019. Subduction-Related Sedimentary Basins of the US Cordillera. 

In The sedimentary basins of the United States and Canada (pp. 477-510). Elsevier.

https://www.researchgate.net/publication/223827907_Chapter_11_Subduction-Related_Sedimentary_Basins_of_the_USA_Cordillera

https://www.researchgate.net/profile/Raymond_Ingersoll

 

Lash, G.G., 1985. Recognition of trench fill in orogenic flysch sequences. 

Geology, 13(12), pp.867-870.

https://pubs.geoscienceworld.org/gsa/geology/article-abstract/13/12/867/203777

 

Underwood, M.B. and Bachman, S.B., 1982. Sedimentary facies associations 

within subduction complexes. Geological Society, London, Special Publications, 

10(1), pp.537-550.

http://www.science.earthjay.com/instruction/HSU/2015_fall/GEOL_332/lectures/lecture_04/underwood_bachman_1982_sedimentary_facies_subduction_complexes.pdf

 

Wakita, K., 2019. Tectonic setting required for the preservation of sedimentary 

mélanges in Palaeozoic and Mesozoic accretionary complexes of southwest 

Japan. Gondwana Research.

https://www.sciencedirect.com/science/article/pii/S1342937X19300814

 

Westbrook, G.K., Ladd, J.W., Buhl, P., Bangs, N. and Tiley, G.J., 1988. Cross section 

of an accretionary wedge: Barbados Ridge complex. Geology, 16(7), pp.631-635.

http://eps.mcgill.ca/~courses/c350/lecturestuff/feb27/Westbrook88.pdf

http://eps.mcgill.ca/~courses/c350/lecturestuff/feb27/

 

Yours,

 

Paul H.

[Hapchazzard]

Thank you everyone, but especially Oxytropidoceras for all of the info! Will look at the papers you posted, they look very informative and pertinent to what I'm asking about.