VERY LOW POWER GATED CRYSTAL OSCILLATOR
The circuit gates the output of a continuously operating 32KHz crystal oscillator to the input of a C-MOS buffer when clock pulses are needed. The technique gets around the problem of a slow starting crystal oscillator by keeping the oscillator going and switching on a transistor power stage only as needed. The method keeps the standby power consumption to a very low 1uA when used with a 3v supply.

Charge Pump Circuits    Crystal Oscillators
Master Schematic Category List - David A. Johnson, P.E.