The Chalk Group deposited on the Schill Grund Platform in Dutch offshore comprises a near complete early Danian to late Cenomanian chalk succession. Such a long record (~30 Myrs) allows for the study of long period (>1 Myr) astronomical cycles providing insights into amplitude modulation of astronomical cycles. A 405kyr eccentricity-based tuning was created for one gamma-ray log and one thorium well-logs which go through the Chalk Group. These results were tuned to astronomical solution La2010d, which were then be used to study aspects of long period astronomical cycles. Firstly, the amplitude modulation of the 405 kyr eccentricity by long period astronomical cycles was studied, which indicates that secular resonance transitions took place at ~85 Ma and ~92 Ma. The secular resonance transition at ~92Ma shifted the duration of the 2.4 Myr eccentricity cycle to a 1.2 Myr period while the resonance transition at ~85 Ma shifted the period shifted back 2.4 Myr. The amplitude modulation records were also compared to the amplitude modulation records of astronomical solutions. None of the astronomical solutions accurately model the observed resonance transition. The second result is related to Ocean Anoxic Event II (OAEII). The 2.4 Myr cycle is at a maximum ~ 400kyr before the onset of OAEII and progressively transitions towards a minimum during OAEII, as the 1.2 Myr obliquity cycle peaks during OAEII. This phase relationship between these astronomical cycles leads to a progressive increase in the contribution of the obliquity to the astronomical-insolation signal during OAEII.