Deep sea sediment records provide you with continuous and (relatively) unaltered records going back into the Cenozoic, preserving the changes accompanying the transition from a much warmer world to our current one with permanent polar ice caps – that’s a pretty useful thing to have. You get much older rocks on the continents, of course, but the sequences are cut up by faulting and are often more altered, so our knowledge of those older times is a lot less detailed and harder to interpret. Some of us like the challenge though!

I should’ve quantified the time frames I’m talking about with this kind of research. It’s all relative.

I’m not talking about deep geologic time here…instead of the word
“ancient oceans” I should’ve said “past oceans” or something else.

A lot of source-to-sink studies are quantifying physical/chemical transfer of material over the last century. Some are going into glacial-interglacial time frames and some into the millions of years time frame. So when I said ‘ancient oceans’ I didn’t mean Archean or anything.

You say: “They [deep sea records] are great for the recent past, but useless for ancient stuff.” I’m talking about paleoceanography…yes, of course we can’t study the truly ‘ancient’ because there are no records. But, is there not a distinction between paleoceanography and oceanography? Furthermore, if you read the Deep Sea News blog, most of it is biological topics of the modern ocean. I was asked to write a post that delves into marine geology by the organizers of that blog

So I guess same goes with the ‘ultimate resting place’ comment. Of course it doesn’t stay there forever…this is all within the context of investigating sediment transfer and how it relates to other Earth surface processes. So in the last paragraph of the post, I mention studying these patterns back to 7,000 years ago. If you study the modern ocean and/or modern Earth surface processes, say the last century at most, then that time frame is only ~1.5% of the last 7,000 years.

So, the lesson is we all oughtta put a ballpark number with anything we are talking about…at least within an order of magnitude. The Earth is so dynamic across such a broad temporal scale that nearly everything can be described as a transient feature and we won’t be able to communicate with each other with the terms ‘ancient’ and ‘recent’.

“As we all know, the deep sea contains fantastic records of ancient oceanic conditions.”

The deep sea record tells us nothing at all about ancient oceans, because the very oldest deep sea basins are only 4% of the age of the Earth. They are great for the recent past, but useless for ancient stuff.

“ultimately the deep sea is the final resting place.”

As mentioned previously, the deep sea floor is a transient feature, so any sediment that ends up there will soon be transported to a subduction zone, scraped off, and stacked back up on a continent again. And I reckon that continental redidence times are, in general, considerably longer than oceanic ones. In otherwords, sand grains spend most of their lifetime as continental/ cratonic sediments locked up in sandstone, and only briefly go for dips down to the sea floor before getting tossed back up as a thrust sheet.