[tchitra]

While the analysis contained in this article is rather arbitrary, blustery and imprecise, there is a mechanism by which blockchains can serve as 'partially synchronized clocks.' One interesting facet about Bitcoin is that the model under which you analyze the effect of network delays can give you different results about how unsynchronized local copies of the blockchain can become. In the paper, "Analysis of Blockchains in Asynchronous Networks" [0], a certain (and more realistic) model is used in which adversarial miners are allowed to delay forwarding of blocks that they receive. The goal of this model is to describe how networking can account for changes to the probability of selfish mining [1]. The authors of [0] prove that for Bitcoin, under some assumptions about the maximum delay an adversary can use and the block production rate, is consistent because it has both a lower bound on how much chains between different participants can differ as well as an upper bound about how far ahead a single participant can grow their chain. Note that all of these statements have to be interpreted as statements "with high probability" relative to security parameters.

In [0], the authors argue that Bitcoin, in particular, is a partially-synchronized global clock, and they take advantage of it in [2] to make a hybrid blockchain-DB system that provides more traditional eventual consistency guarantees.

NOTE: I'm not an author of any of these papers, just a casual observer

[0] https://eprint.iacr.org/2016/454.pdf

[1] https://arxiv.org/abs/1311.0243

[2] https://eprint.iacr.org/2016/917.pdf