Wiley, Terra Nova, 1(19), p. 65-73, 2007
DOI: 10.1111/j.1365-3121.2006.00716.x
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Our results prove that glacio-eustatic sea level oscillations in the early Oligocene were dominantly obliquity controlled with additional influence of the ∼100- and 405-kyr eccentricity cycles. This was derived from spectral analysis of resistivity records from an extended downhole section of the Boom Clay succession in Belgium, that reveals a prevailing obliquity control on the laterally persistent metre-scale alternations of shallow marine silt- and claystones in the Rupelian historical stratotype succession. These direct measurements of sea level variations in a shallow marine setting corroborate that variations with similar frequencies in benthonic oxygen isotope records from the open ocean indeed reflect, at least partly, ice volume change. A very tentative astronomical tuning has been established for the Boom Clay succession which awaits future confirmation with the addition of more accurate age calibration points.