Palynological fluorescence in hinterland reconstruction of a cyclic shallowing-up sequence, Pliocene, Papua New Guinea

Variations in fluorescence characteristics of contemporaneous and reworked palynological particles are documented through a cyclic shallowing-upward sequence of Lower Pliocene mudstones of the Orubadi Formation, in the Puri Anticline of the Papuan Foreland Basin, Papua New Guinea. Fluorescence of palynological particles may be affected by age, oxidation and thermal maturation and therefore provides information about tectonic and palaeogeographical events in the source area of the particles—the New Guinea Fold and Thrust Belt. Palynological particles have been identified with different fluorescence properties and sources: (1) rocks at the southern (proximal) edge of the fold and thrust belt—not greatly affected by tectonic events; (2) rocks at a more distant location within the fold and thrust belt—affected by tectonic controlled changes in gradient, orographic rainfall and fluvial transportation; and (3) contemporaneous vegetation—affected by tectonic-controlled changes in altitude and fluvial transportation. Variation in the fluorescence of palynological particles from these sources allows interpretations to be made about timing of thrusting events, changes in the weathering and transportation regime and the variations in accommodation space in the foreland basin.