Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic

Abstract

Eccentricity, obliquity, and precession are cyclic parameters of the Earth's orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce "grand orbital cycles," but the behavior and the paleoenvironmental consequences of these cycles remain debated for the Mesozoic owing to the chaotic diffusion of the solar system in the past. Here, we test for these cycles from the Jurassic to the Early Cretaceous by analyzing new stable isotope datasets reflecting fluctuations in the carbon cycle and seawater temperatures. Our results document a prominent cyclicity of ∼9 My in the carbon cycle paced by changes in the seasonal dynamics of hydrological processes and long-term sea level fluctuations. These paleoenvironmental changes are linked to a great eccentricity cycle consistent with astronomical solutions. The orbital forcing signal was mainly amplified by cumulative sequestration of organic matter in the boreal wetlands under greenhouse conditions. Finally, we show that the ∼9-My cycle faded during the Pliensbachian, which could either reflect major paleoenvironmental disturbances or a chaotic transition affecting this cycle.orbital cycles | carbon cycle | paleoclimate | eustatism | Mesozoic

Jurassic Sea-Level Variations: A Reappraisal

“…18 O isotopic data from Jurassic belemnites collected from the European sections (from the Sinemurian through Tithonian interval; see Martinez and Dera, 2015) were plotted against the sea-level curve (and smoothed by Robust Lowess Regression) for comparison (see GSA Data Repository Fig. S1 1 ).…”

Palaeoclimatic oscillations in the Pliensbachian (Early Jurassic) of the Asturian Basin (Northern Spain)

“…Hesselbo et al ( , 2007, Cohen et al (2004) and Kemp et al (2005), associated it with the massive release of gas methane linked with the intrusion of the Karoo-Ferrar large igneous province onto coalfields, as proposed by McElwain et al (2005) or with the contact metamorphism by dykes and sills related to the Karoo-Ferrar igneous activity into organic-rich sediments (Svensen et al, 2007). Martinez and Dera (2015) proposed the presence of fluctuations in the carbon cycle during the Jurassic and Early Cretaceous, resulting from a cyclicity of ∼ 9 My linked to a great eccentricity cycle, amplified by cumulative sequestration of organic matter. Nevertheless, this ∼ 9 My cycle has not been evidenced in the Pliensbachian deposits of several parts of the World Tada, 2013, 2014) and cannot be evidenced in the Pliensbachian deposits of the Asturian Basin either.…”

“…Nevertheless, this ∼ 9 My cycle has not been evidenced in the Pliensbachian deposits of several parts of the World Tada, 2013, 2014) and cannot be evidenced in the Pliensbachian deposits of the Asturian Basin either. The disruption of this cyclicity recorded during the Pliensbachian could be linked to chaotic behaviour in the solar system (Martinez and Dera, 2015) possibly due to the chaotic transition in the Earth-Mars resonance (Ikeda and Tada, 2013). Data from Japan suggest that this disruption, which developed from the Hettangian to the Pliensbachian Tada, 2013, 2014) was possibly linked to the massive injection of CO 2 from the eruptions of the Central Atlantic Magmatic Province to the Karoo-Ferrar eruptions (Prokoph et al, 2013) which destabilized the carbon fluxes, reducing or dephasing the orbital imprint in the δ 13 C over millions of years (Martinez and Dera, 2015).…”

Sedimentary characterization of the carbonate source rock of Upper Kimmeridgian Parnac Formation of the Aquitaine Basin (Quercy area)

“…Whether organic matter accumulation is ruled by important primary productivity or by anoxic conditions, which help preserving organic matter, has been a long-standing matter of debate (e.g., Pedersen and Calvert, 1990;Bordenave, 1993). In the Kimmeridgian of northwestern Europe, primary productivity has likely been fuelled by monsoonal conditions, involving important fluvial discharges in the Tethys Ocean (Martinez and Dera, 2015;Armstrong et al, 2016). Accordingly, high planktonic production is inferred to have been the main driver of organic matter accumulation in distal platforms, while local development of anoxic conditions could further enhance preservation (e.g., Disnar and Ramanampisoa, 1995;LallierVergès et al, 1995).…”