Electronic Supplementary Material 2: Identification of Mineralogical Composition by Confocal Raman-Spectroscopy Methodology: The mineralogy of cuttings of the drilling Löpsingen 2012 was investigated by a confocal Horiba Jobin-Yvon LabRam-HR 800 UV Raman spectrometer with attached Olympus BX41 microscope. The excitation wavelength was the 488 nm line of a diode laser (Coherent Sapphire) with a laser power of 50 mW at the laser exit (ca. 8 mW at the sample). Using an Olympus Mplane 100x objective with a numerical aperture of 0.9 and closing the confocal hole to 100 mm resulted in a lateral resolution of ca. 1 µm and a depth resolution of ca. 5 µm. The combination of 488 nm excitation, a grating of 600 l/mm and a CCD detector with 1024 x 128 pixels yielded a spectral dispersion of better than 2.1 cm-1 per pixel. In general spectra were collected in one spectral window between 100 and 2100 cm-1. When necessary the range was enlarged to 100 to 4000 cm-1 (yielding 3 spectral windows). The acquisition time varied between 5 and 30 s per spectral window, depending on the level of fluorescence. To improve the signal to noise ratio every spectral window was measured 2 to 16 times. For calibration of the spectrometer a silicon standard with a major band at 520.4 cm-1 was used. All spectra were recorded and processed using LabSpec 5 software. The minerals were identified on the basis of the Horiba Jobin-Yvon database for minerals and reference spectra collected on mineral specimens of the Geoscience Museum of the Georg-August University Göttingen. (i) Reference spectra of well-ordered carbonate phases Calcite Dolomite Magnesite T n1 L n4 Aragonite

(ii) Analytical results Sample Lop 15 (drilling Löpsingen, micrite from 15 m depth): calcite calcite Sample Lop 23 (drilling Löpsingen, micrite from 23 m depth): calcite calcite

aragonite (arag) and organics (org, C-H, O-H) Sample Lop 32 Hydrob (drilling Löpsingen, Hydrobia shell from 32 m depth): aragonite (arag) and organics (org, C-H, O-H) arag C-H O-H org Sample Lop 32 Hydrob (drilling Löpsingen, argillaceous marl from 32 m depth): Poorly ordered (biogenic?) calcite, well ordered calcite and carbonacous matter calcite carbonacous matter

Sample Lop 37 (drilling Löpsingen, micrite from 37 m depth): calcite with strong fluorescence calcite Sample Lop 50 Clado (drilling Löpsingen, Cladophorites tube from 50 m depth): calcite and minor sulphate, with strong fluorescence calcite sulphate Cc SO42- Cc

Sample Lop 53 (drilling Löpsingen, dolomicrite from 53 m depth): calcite, Ca-rich dolomite, carbonaceous matter carbonacous matter calcite Ca-dolomite 1085.5 1094.2 Sample Lop 58 (drilling Löpsingen, dolomicrite from 58 m depth): Poorly ordered (biogenic?) calcite, well ordered calcite, Ca-dolomite, and carbonaceous matter poorly ordered calcite carbonacous matter calcite Ca-dolomite carbonacous matter

Sample Lop 63 (drilling Löpsingen, dolomicrite from 63 m depth): calcite, Ca-rich dolomite, carbonaceous matter calcite carbonacous matter Ca-dolomite Sample Lop 67 (drilling Löpsingen, dolomicrite from 67 m depth): calcite, Ca-dolomite, and carbonaceous matter 1084.9 1092.8 150.2 169.7 carbonacous matter calcite Ca-dolomite

Sample Lop 75 (drilling Löpsingen, dolomicrite from 75 m depth): Ca-rich dolomite, minor sulphate, carbonaceous matter carbonacous matter Ca-dolomite sulphate Sample Lop 76 (drilling Löpsingen, dolomicrite from 76 m depth): Ca-dolomite, and carbonaceous matter carbonacous matter Ca-dolomite

Sample Lop 78 (drilling Löpsingen, dolomicrite from 78 m depth): Poorly ordered (biogenic?) calcite, well ordered calcite, Ca-rich dolomite, carbonaceous matter poorly ordered calcite carbonacous matter well ordered calcite Ca-dolomite carbonacous matter