Hi. I’m in New England at the moment, but can give you a quick answer [if you google 'varve' you'll be overwhelmed with info]. By definition varves are annual cycles. Most commonly the term is applied to glacial lake seds. If marine, oxygen isotopes can be used to get paleotemperatures [perhaps in lakes too if any calcareous plankton are found]. The Greenland ice cores are varved in that they have annual cycles with data going back 15K+ years and trapped gas can yield O-isotope paleotemp data. Hope this helps.

I should be the last one here to deny anyone their poetic license!

On a more serious note, I’d be very interested in hearing your views on Andean lake sediments as temperature (or ENSO) proxies.

For any proxy to be reliable, it must be coherent over a wide range of frequencies with the signal of interest. Varves may indeed provide some useful indication of precipitation intensity over decadal time-scales or longer. But with the latter being being only tenuously coherent with similar-scale temperature variations, it seems difficult to make a rigorous scientific case for any supposed thermometry by varves.

is it not facile and a bit like that other blog’s errors to dismiss work in a field before you have brought yourself up to steam?

Amen!

… thixotropy …

Thixotropy? What rhymes with thixotropy??

For a direct linkage, temperatures taken in the instrumented era have to deal with extremely recent sediments. It is well known in geology that it can take many orders of magnitude more time for the normal effects of dewatering, compaction, metamorphism (if any), shearing, folding, intrusion by other bodies, alteration of provenance, thixotropy and so on before a sedimentary pile can be regarded as having completed its formation – if it ever does complete its formation. Even 5000 feet down in the Mississippi mud there are active processes at work.

To derive temperature properties from recent varves, one has either to go via an intermediate (like dendrothermometry or some types of isotope work), or determine the rather exact progression from a sediment layer put down this year to one put down thousands of years ago. Where does the varve under study sit in this spectrum of change? The answer is generally unknown within adequate accuracy.

the brave field of sedimentology.

Is that, like, naturopathic medicine, or something? Y’know, like Dead Sea facial muds or something like that?

Mann said with a grin
As he worked on his spin
This Cherry’s so ripe I must pluck it.

Bender: precisely my point – there may be some ancient varves that can be used as temperature proxies, but certainly not all (many) and who is to judge which ones are appropriate.

On varves, I have no position
this is my humble admission
They measure the height
That seems about right
Who gives a s**t about deposition

They said with a grin
As they worked on their spin
This grant is so ripe we can pluck it.