Guided by the duality of turbulence (random versus coherent we seek coherent
structures in the turbulent velocity field of molecular clouds, anticipating
their importance in cloud evolution. We analyse a large map (40' by 20')
obtained with the HERA multibeam receiver (IRAM-30m telescope) in a high
latitude cloud of the Polaris Flare at an unprecedented spatial (11") and
spectral (0.05 km/s) resolutions in the 12CO(2-1) line. We find that two
parsec-scale components of velocities differing by ~2 km/s, share a narrow
interface (<0.15 pc) that appears as an elongated structure of intense
velocity-shear, ~15 to 30 km/s/pc. The locus of the extrema of
line--centroid-velocity increments (E-CVI) in that field follows this
intense-shear structure as well as that of the 12CO(2-1) high-velocity line
wings. The tiny spatial overlap in projection of the two parsec-scale
components implies that they are sheets of CO emission and that discontinuities
in the gas properties (CO enrichment and/or increase of gas density) occur at
the position of the intense velocity shear. These results disclose spatial and
kinematic coherence between scales as small as 0.03 pc and parsec scales. They
confirm that the departure from Gaussianity of the probability density
functions of E-CVIs is a powerful statistical tracer of the intermittency of
turbulence. They disclose a link between large scale turbulence, its
intermittent dissipation rate and low-mass dense core formation