Try subset
:
> subset(myts, diff(myts) > 10)
2013-07-09 12:04:00 2013-07-09 12:07:00 2013-07-09 12:10:00 2013-07-09 12:22:00
1621.04 1630.75 1645.89 1616.67
2013-07-09 12:28:00 2013-07-09 12:32:00 2013-07-09 12:37:00 2013-07-09 12:38:00
1631.87 1650.43 1524.28 1603.65
2013-07-09 12:39:00 2013-07-09 12:40:00 2013-07-09 12:41:00
1622.49 1636.68 1652.10
Use abs(diff(myts))
if either direction is needed.