The aim of this work is to investigate the time spectral features of the main geomagnetic field fluctuations as measured on the Earth's surface in connection with a nontraditional turbulent dynamics of the fluid motions in the outer layers of the Earth's liquid core. The average geomagnetic field spectrum is found to be a power law, characterized by a spectral exponent alpha approximately -11/3, on time scales longer than 5 yr. We discuss the spectral exponent in connection with an intense magnetic field in the Earth's core and with a vortex coalescence process in a regime of drift-wave turbulence.