Publikationsdatum:
2017-04-04
Beschreibung:
An integrated high-resolution magnetobiocyclostratigraphy including radioisotopic dating and astronomical
tuning is presented for the interval between 15.29 and 14.17 Ma in the marine La Vedova section in northern
Italy. The natural remanent magnetization is carried by the iron sulphide greigite and the resultant
magnetostratigraphy can be correlated straightforwardly to the interval ranging from C5Bn.2n to C5ADn in
the Astronomically Tuned Neogene Time Scale (ATNTS2004). Spectral analysis on high-resolution magnetic
susceptibility and geochemical proxy records in the depth domain and, using our magnetobiostratigraphic
age model, in the time domain demonstrate that the various scales of cyclicity in the section are related to
astronomical climate forcing. Starting from our initial age model, larger-scale cycles were first tuned to
eccentricity. This first-order tuning was followed by tuning the basic cycle to precession and boreal summer
insolation using inferred phase relations between maxima in Ca/Al, redox-sensitive elements and Ba, and
minima in magnetic susceptibility, and maxima in precession and minima in obliquity and boreal summer
insolation. Our astronomical ages for reversal boundaries are supported by analysis of sea floor spreading
rates and should replace the existing ages in the ATNTS2004 lacking direct astronomical control. Two major
steps in the geochemical proxy records, astronomically dated at 15.074 and 14.489 Ma, coincide with abrupt
changes in sedimentation rate, and are the result of the combined effect of the ∼400-kyr eccentricity cycle
superimposed upon a longer-term climatic or tectonic induced trend.
Beschreibung:
Published
Beschreibung:
254–269
Beschreibung:
2.2. Laboratorio di paleomagnetismo
Beschreibung:
JCR Journal
Beschreibung:
restricted
Schlagwort(e):
Middle Miocene
;
Langhian
;
Mediterranean
;
astronomical tuning
;
palaeomagnetism
;
biostratigraphy
;
environmental changes
;
orbital forcing
;
04. Solid Earth::04.04. Geology::04.04.10. Stratigraphy
;
04. Solid Earth::04.05. Geomagnetism::04.05.06. Paleomagnetism
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
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