Supplementary Information

MILANKOVITCH AND SEA LEVEL CONTROLS DURING THE TOARCIAN OCEANIC

ANOXIC CRISIS: IMPLICATIONS FOR THE TOARCIAN TIMESCALE AND CARBON

ISOTOPE STRATIGRAPHY

Wolfgang Rübsam, Petra Münzberger, Lorenz Schwark

Stratigraphic framework

Core FR-210-078 (this study) is one of a series of drill-cores recovered in southern

Luxembourg during a tunnel construction campaign in 2008. These cores penetrate lower

Jurassic sediments spanning the uppermost Pliensbachian to middle Toarcian, mainly

represented by the Grès médioliasiques formation (upper Pliensbachian and lowermost

Toarcian), as well as the Schistes Carton and the Marnes à Bifrons formations (lower and

middle Toarcian). Detailed biostratigraphic investigations by Guérin-Franiatte et al. (2010)

provide a very robust biostratigraphic framework (Fig. S1). The Grès médioliasiques Fm

corresponds to the upper spinatum zone (uppermost Pliensbachian, lm3, fig. S1) and to the

tenuicostatum zone (lower Toarcain), whereby the tenuicostatum zone reaches a thickness of

about 6 m (lo1a, Fig. S1). The tenuicostatum-serpentinum boundary is located within the

lowermost Schistes Carton Fm, whereby the uppermost tenuicostatum zone is represented by

distinctly laminated bituminous sediments. The total thicknesses of the serpentinum and

bifrons zones vary between 25 and 30 m, whereby the basal part of the bifrons zone is still

rich in organic matter and thus is attributed to the Schistes Carton facies (Fig. S1). In the

Lorraine Sub-Basin the total thickness of organic-rich sediments of the Schistes Carton facies

can reach a thickness of up to 50 m and spread over the uppermost tenuicostatum zone,

serpentinum zone and the lower bifrons zone (Binz et al., 1984). In Core FR-207-142 the

Schistes Carton Fm spans a sediment succession of about 31.80 m (lo1 + lower lo2 in Fig.

S1). The boundary between Schistes Carton Fm and Marnes à Bifrons Fm is not very precise

but can be placed at core depth of approximately 23.80 m (Münzberger, pers. comm.).

Furthermore, Core FR-207-142 was subjected to detailed biostratigraphic investigations and

was used as reference core (Guérin-Franiatte et al., 2010). Biostratigraphic boundaries were

transferred to Core FR-210-078 using lithological and geochemical data (e.g. gamma ray,

carbonate content). The core correlation is shown in figure S1. For details on biostratigraphy

refer to Guérin-Franiatte et al. (2010). The biostratigraphy proposed here shows an excellent

match with biostratigraphic data available from outcrops in southern Luxembourg (Hermoso et

al., 2014 and references therein).

Fig. S1: Occurrence of ammonites in Core FR-207-142 and inferred biostratigraphy (Guérin-Franiatte et

al., 2010). Biostratigraphy of Core Fr-210-078 (this study) is adapted from Core FR-207-142 (Guérin-

Franiatte et al., 2010 and Münzberger, pers. comm.). Both cores are stored at the University of Kiel and

were investigated for geochemical proxy parameters. Core-correlation (lateral distance in field is approx.

1.5 km) is based on lithological and geochemical parameters (e.g. gamma ray, carbonate content).

Depths in red indicate biostratigraphic boundaries, depths in black indicate lithological boundaries. In

Core FR-210-078 (this study) the serpentinum-bifrons boundary is placed at around 7 m, indicating that

approx. 2.5 m of the uppermost serpentinum zone are missing. Sedimentological inspection shows that

the basal Schistes Carton formation (31.97 – 30.75 m) differs from the regular bituminous marls (9.55 –

30.75 m). The most significant lithological alternations (distinct vs. indistinct laminated) are observed in

the interval corresponding to the elegantulum subzone.

Fig. S2: Photographs taken from selected core intervals show significant differences in lithology that are well expressed by variations in MS-data and sediment color as well as by fluctuations in carbonate and organic matter content. Width of each photograph is about 7 cm. The sediment color might be obscured as the contrast of the photographs was increased in order to highlight sediment structures.

Sediment geochemistry

Fluctuations in sediment color expressed in the L*a*b* color space show a strong correlation

with lithological changes. Especially a*- and b*-values are most sensitive toward lithological

changes and are clearly delinated between distinctly laminated (bituminous) sediments that

show high a*- and b*-values and indistinctly laminated sediments that show low a*- and b*-

values (Fig. S3). The high positive correlation observed between a*-values and TOC content

(R2= 0.64) confirms that organic matter content has a strong impact on this parameter (Fig.

S4). Changes in L*-values allow to distinguish between the bioturbated sediments

corresponding to the Grès médioliasiques Fm and the laminated sediments of the Schistes

Carton Fm. However, lithological changes within the Schistes Carton Fm are not represented

very precisely, when compared with a*- and b*-values. The lower correlation between

lithological changes and L*-values indicate that several factors affect this parameter (e.g.

organic matter content, carbonate content, mineralogy).

A general decreasing trend in magnetic susceptibility (MS) is observed throughout the

sediment succession investigated, whereby the highest values are bound to sediments

corresponding to the Grès médioliasiques Fm. Sediments corresponding to the Schistes

Carton Fm are characterized by relatively low MS-values (Fig. S3). Fluctuations in this

parameter throughout the Schistes Carton Fm distinguish between distinct-laminated and

indistinct-laminated horizons (Fig. S3). Investigations by Boulila et al. (2014), which studied

time-equal sediments in the Central Paris Basin (Sancerre drill core), confirm that fluctuations

in magnetic susceptibility are related to changes in the abundance of terrigenous-derived

clays. Changes in magnetic susceptibility therefore can be attributed to different degrees of

dilution of the clay minerals by in situ produced marine carbonate (e.g. Ellwood et al., 2000).

The negative correlation between MS-values and carbonate content observed throughout the

Schistes Carton Fm confirm that MS-values are linked to changes in carbonate content (Fig.

S4). A positive correlation between MS-data and carbonate observed throughout the Grès

médioliasiques Fm, might indicate that iron-bearing carbonates contribute to changes in MS-

values (Fig. S4).

Fig. S3: Evolution of sediment color (expressed in L*a*b* color space), magnetic susceptibility (MS) and

carbonate content in Core FR-210-078. Indistinctly laminated light-grey intercalations within the

laminated dark-grey marls of the Schistes Carton Fm are well expressed by all parameters and are

highlighted by light grey bars. High a*- and b*-values and high carbonate content with low MS-values

are restricted to the laminated horizons of the Schistes Carton Fm. The basal Schistes Carton Fm has

the lowest carbonate content (<< 10wt.%). Intervals 1 to 4 were distinguished by sedimentological and

geochemical data and were analyzed via spectral analysis separately (I3: Interval 3; 30.75 – 31.97 m).

Fig. S4: Scatter plot of carbonate content vs. MS-values (left) shows a positive correlation for samples

corresponding the Grès médioliasiques Fm and a negative correlation for samples corresponding the

Schistes Carton Fm. The positive correlation between carbonate and MS-values might indicate

contributions of Fe-bearing carbonates such as ankerite or siderite. The negative correlation between

carbonate and MS-values in sediments of the Schistes Carton Fm indicates variable degrees of dilution

of terrigenous-derived clay minerals by marine carbonate. The positive correlation observed between

a*-values and TOCcf (total organic carbonate on carbonate-free base) indicate that changes in organic

matter abundance (and possible associated sulfides) have a strong impact on this parameter.

Supplementary Figures

Fig. S5: 2π-MTM power spectrum for Intervals 1+2 (top) and for Interval 4 (bottom) of a*-, b*-, and MS-

data (MS-data within Interval 4 analyzed from 34.00 – 38.00 m). Throughout Intervals 1+2 (top) the

presence of regular cycles with a mean wavelength of around 3.10 m, 1.47 m, 1.20 m, 0.65 and 0.46 m

is confirmed. The presence of regular cycles with a mean wavelength of around 1.20 m, 0.50 m, 0.43 m

and 0.30 m is confirmed for Interval 4. In Interval 4 slightly different wavelengths of the low-frequency

compounds are observed between a*- and b*-data. This discrepancy can be attributed to the incomplete

removal of preferentially low-frequency cycles by erosional events. On the base of their cycle hierarchy

we attribute those cycles to short eccentricity (E), obliquity (O) and precession (P) based cycles.

Fig. S6: Filter output for a*-, b*- and MS-values of significant spectral peaks (see Fig S3A). The 100 kyr

eccentricity, 35 kyr obliquity and 21 kyr precession components are well expressed in the parameters

investigated. The 100 kyr eccentricity component is always very weak in MS-data, whereas sediment

color seems to be more sensitive towards this frequency component. By analyzing Intervals 1 + 2 the

presence of a 100 kyr eccentricity component is confirmed for Interval 2 and the 1.10 m cycle within this

interval can be clearly attributed to the obliquity component. The 100 kyr eccentricity component might

be weak in Interval 2 as this interval represents only a short period of time (around 290 to 315 kyr) and

thus cover only 3 short eccentricity cycles. Cycles were extracted using the Gaussian filter with a

bandwidth of 0.2 for Intervals 1 and 2. A bandwidth of 0.25 was used to extract cycles in the Interval 4.

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