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Orbital forcing recorded in subtidal cycles from a Lower Miocene siliciclastic–carbonate ramp system (Central Italy)
Author(s) -
Brandano Marco,
Corda Laura,
Mariotti Goffredo
Publication year - 2005
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/j.1365-3121.2005.00630.x
Subject(s) - siliciclastic , geology , terrigenous sediment , milankovitch cycles , paleontology , facies , orbital forcing , sedimentary depositional environment , carbonate , lithology , sedimentary rock , structural basin , metallurgy , glacial period , materials science
Abstract Metre‐scale siliciclastic–carbonate cycles are the basic depositional motif of the lower Miocene Guadagnolo Formation outcropping in the central Apennines. The mechanisms which formed the mixed‐lithology cycles are still a matter of debate. The mixed siliciclastic–carbonate system discussed in this paper provides a new case study to illustrate the role of orbital forcing in controlling the facies evolution and cyclic stacking of small‐scale sequences deposited on the outer sector of a ramp. Two sections are discussed that display mixed siliciclastics and carbonates arranged in upward‐shallowing cycles. Each cycle shows an upward decrease in the terrigenous input and a parallel increase in benthic fauna. Time‐series analyses indicate the cyclic carbonate‐terrigenous pattern to be largely controlled by orbital forcing in the Milankovitch frequency band. Coupling of climate change and sea‐level fluctuations in tune with orbital cycles are proposed as driving mechanisms.