20 Myr of eccentricity paced lacustrine cycles in the Cenozoic Ebro Basin

Abstract

Long-period orbital forcing is a crucial component of the major global climate shifts during the Cenozoic as revealed in marine pelagic records. A complementary regional perspective of climate change can be assessed from internally drained lake basins, which are directly affected by insolation and precipitation balance. The Ebro Basin in northeastern Iberia embraces a 20 Myr long continuous sedimentary record where recurrent expansions and retractions of the central lacustrine system suggest periodic shifts of water balance due to orbital oscillations. In order to test climatic (orbital) forcing a key-piece of the basin, the Los Monegros lacustrine system, has been analyzed in detail. The cyclostratigraphic analysis points to orbital eccentricity as pacemaker of short to long-term lacustrine sequences, and reveals a correlation of maxima of the 100-kyr, 400-kyr and 2.4-Myr eccentricity cycles with periods of lake expansion. A magnetostratigraphy-based chronostratigraphy of the complete continental record allows further assessing long-period orbital forcing at basin scale, a view that challenges alternate scenarios where the stratigraphic architecture in foreland systems is preferably associated to tectonic processes. We conclude that while the location of lacustrine depocenters reacted to the long-term tectonic-driven accommodation changes, shorter wavelenght oscillations of lake environments, still million-year scale, claims for a dominance of orbital forcing. We suggest a decoupling between (tectonic) supply-driven clastic sequences fed from basin margins and (climatic) base level-driven lacustrine sequences in active settings with medium to large sediment transfer systems.

Middle to Late Miocene Eccentricity Forcing on Lake Expansion in NE Tibet

“…Middle Miocene lake expansions in southeast Kazakhstan, on the westerly wind pathway and beyond the EASM effect, have been shown to be dominantly controlled by eccentricity (Voigt et al, 2017). Similarly, middle-late Miocene lacustrine expansions in the circum-Mediterranean region have been shown to correlate with~100-and 400-kyr eccentricity maxima (Abels et al, 2010;Valero et al, 2014). The similarity between these records and our results suggests that westerly derived moisture supply could have been the dominant player in middle to late Miocene lake expansions in North Tibet.…”

Insights Into the Crustal‐Scale Dynamics of a Doubly Vergent Orogen From a Quantitative Analysis of Its Forelands: A Case Study of the Eastern Pyrenees

“…The Ebro foreland basin became fully continental during the deposition of the uppermost part of the Cardona evaporitic Formation at~36 Ma (middle Priabonian; Costa et al, 2010). Widespread nonmarine deposition was then established until the latest Oligocene consisting of the alluvial and fluvial Solsona Formation and equivalent lacustrine deposits in the center of the foreland basin (Figure 3a; García-Castellanos et al, 2003;García-Castellanos & Larrasoaña, 2015;Meigs et al, 1996;Valero et al, 2014).…”

Evolution of the early Antarctic ice ages

“…1A). The record from Site 1264 is the first to unequivocally show that the ∼2.4-My eccentricity cycle paces recurrent episodes of high-amplitude ∼110-ky variability in benthic δ 18 O (9, 19) and provides a new global climatic context in which to understand Oligo-Miocene glacial history, carbon cycling (9, 21), midlatitude terrestrial water balance (22), and mammal turnover rates (23) that show similar pacing. The intervals with particularly strong ∼110-ky cycles are separated by prolonged periods of attenuated ∼110-ky cycle amplitude, indicating that not all ∼2.4-My and 405-ky eccentricity maxima trigger similar cryospheric responses (Fig.…”