Fourier Evidence for High-Frequency Astronomical Cycles Recorded in Early Cretaceous Carbonate Platform Strata, Monte Maggiore, Southern Apennines, Italy
- P. L. de Boer4 and
- D. G. Smith5
Published Online: 29 APR 2009
Copyright © 1994 The International Association of Sedimentologists
Orbital Forcing and Cyclic Sequences
How to Cite
Longo, G., d'Argenio, B., Ferreri, V. and Iorio, M. (1994) Fourier Evidence for High-Frequency Astronomical Cycles Recorded in Early Cretaceous Carbonate Platform Strata, Monte Maggiore, Southern Apennines, Italy, in Orbital Forcing and Cyclic Sequences (eds P. L. de Boer and D. G. Smith), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304039.ch7
Utrecht, The Netherlands
- Published Online: 29 APR 2009
- Published Print: 28 JAN 1994
Print ISBN: 9780632037360
Online ISBN: 9781444304039
- Fourier evidence for astronomical cycles - Early Cretaceous carbonate platform strata;
- depositional cyclothems;
- diagenetic cyclothems;
- gastropod dolomitic limestones;
- stromatolitic and loferitic dolomites
Carbonate peritidal deposits of Early Cretaceous age, widely outcropping in the carbonate platform sequence of southern Italy, carry distinct signals of cyclicity in the Milankovitch band. We have studied the depositional and diagenetic facies organization of a c. 100-m-thick sequence of Barremian age, at Monte Raggeto (Monte Maggiore Mountains, near Naples), where, from a total of 60m analysed at centimetre scale, two sedimentary modules have been recognized.
1 Depositional cyclothems: rare, made of one or more subtidal–supratidal couplets and topped by supratidal intervals.
2 Diagenetic cyclothems: very common, made of dominantly subtidal intervals which show emersion-generated features (karst, reddened surfaces) at the top.
Cyclothems along the sequence tend to group into fairly regular intervals, each about 10m thick, formed by sets of seven to nine cyclothems. This trend is confirmed by Fourier analysis of the data, showing periodicities at 105 and 950 cm. Moreover, the mathematical processing of the total data set shows also two shorter periodicities at 40 and 72 cm. The algorithm used for the analysis is a modified version of the Deeming code, first written for astrophysical applications.
The set of periodicities obtained (40, 72, 105 and 950cm) can be related to the variations of the insolation constant computed for the Cretaceous; moreover the ratios between the two sets of periodicities, expressed in centimetres and in years respectively, show a very high degree of correlation with those predicted for the main orbital periods in the Cretaceous. We propose that the observed cyclicities indicate Barremian sea-level oscillations induced by high-frequency eustatic control under climatic forcing.
Moreover the link between the ratios of time and depositional periodicity sets appears to be a useful method of assigning a duration to a given periodicity in a sequence, quite independently from a precise determination of biostratigraphic age and/or total thickness of a stage.