"Could also be that the sick banking system of China is about to have a major hiccup".
The huge dollar holdings may be the only incentive for China to stop opposing any harsh measures against Iran.
They have $300 BILLION oil and gas contracts of various kinds with Iran and would likely send in their troops to "maintain peace and stability in the region" (protect their investment). On the other hand if they see that the world economy will crash and drag them into a similar situation of people starving in the streets that the USA would face, they might sign onto destroying the Iranian regime.