I have an animation that I\'m displaying using a UIImageView:
imageView.animationImages = myImages;
imageView.animationDuration = 3;
[imageView startAnimating];
This should do the trick: https://developer.apple.com/library/ios/#qa/qa2009/qa1673.html
It basically tells you what you need to do to pause/resume any CALayer based animation.
If you feel uncomfortable using CALayer methods on UIImageView controlled animation, you could always just make the UIImage array based animation yourself. The code needed is very short, you can take it from here: http://rssv2.blogspot.com/2011/04/animating-series-of-images-with-calayer.html