A complete profile of the Upper Buntsandstein in Northern – an approach in linking stratigraphy and facies by using geochemical data MICHAELA DERSCH-HANSMANN & NICOLA HUG Hessisches Landesamt für Umwelt und Geologie, Rheingaustr. 186, D-65203 Wiesbaden; contact: [email protected]

Fürstenwald A/02-PK01 Borken K47 In 2003, Site Fürstenwald has been drilled depth litholog geochemistry geophysics 2 litholog clay mineralogy palynology sequence trend [m] colour redox (BÜHMANN & RAMBOW 1979: plate 1, modified) (DOUBINGER (coastal onlap curve, 0 terrigenous precipitation geochemical sections cluster analysis with near (Northern Hesse) down to input of evaporites environment and geophysical & BÜHMANN PAUL 2002: facies interpretation sections depth 1981: fig. 4) fig. 2, mod.)

SiO * CaO* V/Zn* (oxid.) 2 (reduc.) [m] 275 m, revealing layers of the lowermost 20 0 Muschelkalk, a complete section of the clay- 20 dominated so-called “Röt-Folge” (repre- 40 beginning transgression PA3 senting the Upper Buntsandstein entirely) 60 GS4 40

retrogradational wet

Röt 4

Röt 4 down to the uppermost sandy units of the sabkha mudplain TM4 TST 80 60 depth Middle Buntsandstein. [m] 4 Our investigations focused on the clay-rich 100 100 80

Borken Borken 100 Sandstone sediments of the Upper Buntsandstein, 120 Sandstone 120 which have been deposited in a widespread dry 120 facies 140 140 Röt 3 LST

aeolian

barren of fossils sabkha environment between the shallow Röt 3 sabkha mudplain GS3 3 HST 140 TM3 marine North German Basin (extending 160 with aeolian 160 southwards down to Lower ) and 180 180 160 deposits TST

fluvially feeded depositions beginning in the Röt 2

Röt 2 retro PA2 200 200 180 Gudensberg gra Sandstone Sandstone Southern part of Hesse. The results allow d. retrogradational wet 2 GS2 LST comparisons with wells nearby (Fig. 1), es- 220 retrogra 220 200 TM2 sabkha mudplain HST

d. distinct regression PA1 pecially with well Borken K47 as shown in TST 240 saline 240 220 retrograd

shallow Röt 1 TM1 Fig. 2. sea 1 . GS1 HST

Röt 1 240 260 retrogra hypersaline 260 LST sea d. transgression massive illite kaolinite chlorite smectite corrensite HST highstand systems tract stratified * schematic geochemical development GS1 = geochemical sections silt stratified to laminated TM1– 4 clay mineral sections TST transgressive clay systems tract laminated PA1– 3 palynological associations gypsum fine sand carbonate sandstone LST lowstand HofgeismarHofgeismar coarse sand sandstone, silicified systems tract medium sand 1 ? WarburgWarburg Hann.Hann. Lithology with geochemical and geophysical interpretation of Site Fürstenwald For comparison: Lithology, clay mineralogy (BÜHMANN & RAMBOW 1979) North GermanHamburg Basin MündenMünden OUBINGER ÜHMANN EhrstenEhrsten sediment composition (geochemical proxies are shown schematically). and palynology (D & B 1981) at well Borken K47 as well as sequence stratigraphical clues after PAUL (2002, modified). FürstenwaldFürstenwald Hannover DocumentaDocumenta WolfhagenWolfhagen KasselKassel

? ElgershausenElgershausen Köln

Rhenish Massif BaunatalBaunatal Eichsfeld-Altmark-Swell

Hessian Depression Geochemical section 1 Geochemical section 2 Geochemical section 3 Geochemical section 4 Thuringian Depression Bohemian GudensbergGudensberg Massif BadBad (GS 1) (GS 2) (GS 3) (GS 4) FritzlarFritzlar WildungenWildungen MelsungenMelsungen FelsbergFelsberg • transgressive devel- • regression at the be- • the sabkha plain • subdivided into two N FritzlarFritzlar BorkenBorken K47KA7KA7 op ment throughout ginning of the Röt 2 reaches its driest parts Vindelician Massif 100 km Basel 10 km HombergHomberg ()(Efze) the Röt 1 • sudden increase in phase • distinctly decreasing basin facies (dominantly evaporitic-pelitic) continuously cored well outcrop areas siliciclastic sabkha facies (dominantly sandy-pelitic) rotary/hammer well Upper Buntsandstein • two-step transgres- siliciclastic input, ten- • culminating in pre- siliciclastic input, in- fluvial facies (dominantly sandy) discontinuously cored well Palaeozoic area of erosion Site Fürstenwald sive development tatively increasing to- dominantly aeolian crease in carbonate North German Basin and its south- Position of Site Fürstenwald and • clearly dominated by wards the upper part accumulation due to • lower part: returned ern margin: Facies and Palaeo- adjacent wells containing Upper the evaporative frac- of GS 2 the blowout of the dry influence of water in geography during the Upper Buntsandstein sediments, all located sabkha mudplain dur- Buntsandstein (after PAUL 2006, in the central part of the Hessian De- tion (halite and gyp- • subdivided into two the sabkha plain, suc- modified). pression. sum) evolutionary parts ing sea level lowstand cessively reinstalling • hypersaline environ- • retrogradational, • transitions towards rather wet conditions ment rather wet sabkha- and off this aeolian • upper part: beginning • conditions change to- mudplain phase are gradational of a new transgres- wards a more marine sion, leading to the environment marine environment of the Lower Muschelkalk Detailed geochemical investigations have been performed on the 253 m clay-rich sed- iment section of the “Röt-Folge“. Our pur- 3 clay/sand/ carbonate + sulphate [rel.%] SiO2 [wt.-%] Al2O3 [wt.-%] TiO2 [wt.-%] SiO2/TiO2 K2O [wt.-%] CaO [wt.-%] MgO [wt.-%] CaO/MgO Sr [ppm] 050 100 0 20 40 60 80 100 0 5 10 15 20 25 0,0 0,2 0,4 0,6 0,8 1,0 0 50 100 150 200 0 2 4 6 8 0 10 20 30 40 50 60 0 5 10 15 20 25 0 5 10 15 0 10000 20000 pose was to find out if it is possible to con- depth [m] firm and further subdivide the lithologically 50 based internal Röt stratigraphy by means Röt 4 100 of geochemical data. Four main geochemi- 3 Röt 3 O 2 150 2 Al GS3 cal sections (GS1–GS4) could be defined, SiO CaO+MgO

200 which are not (all) identical to the strati- Röt 2 secondary gypsum graphic subformations, but mirror geo- GS2 250 GS1 GS4 chemical changes in the sabkha environ- Röt 1

clay/sand/ lithostratigraphic boundary sandstone layers carbonate + sulphate ment. These may be due to climatic, tectonic [rel.%] Na2O [wt.-%] Zn [ppm] V [ppm]V/Zn Zr [ppm] P2O5 [wt.-%] 050 100 0,0 0,5 1,0 1,5 2,0 0 50 100 150 200 0 50 100 150 0 12 3 0 100 200 300 400 500 0,00 0,05 0,10 0,15 0,20 0,25 depth and/or sea level changes. [m] 50 Röt 4

100

BÜHMANN, D. & RAMBOW, D. (1979): Der Obere Buntsandstein (Röt) bei Borken/Hessen, Stratigraphie

und Tonmineralogie. – Geol. Jb. Hessen, 107: 125–138; Wiesbaden. 3 Röt 3 O 2 150 2 Al GS3 DERSCH-HANSMANN, M., HUG, N. & WONIK, T. (in press): Ein vollständiges Röt-Profil (Oberer Buntsand- SiO stein) in Nordhessen - Lithostratigraphie, Sedimentfazies, Geochemie und Geophysik der Kernboh- rung Fürstenwald – Geol. Jb. Hessen; Wiesbaden. CaO+MgO Geochemical sediment compo- OUBINGER ÜHMANN 200 D , J. & B , D. (1981): Röt bei Borken und bei Schlüchtern (Hessen, Deutschland): Pa- Röt 2 sition at Site Fürstenwald (for lynologie und Tonmineralogie. – Z. dt. geol. Ges., 132 (1): 421–449, 5 Abb., 1 Tab., 3 Taf.; Hannover. secondary gypsum GS2 PAUL, J. (2002): Der Röt (Oberer Buntsandstein) in der nördlichen Hessischen Senke. – Geol. Jb. Hes- further details see DERSCH-HANS- sen, 129: 55–78; Wiesbaden. 250 MANN, HUG & WONIK, in press.). GS1 GS4 PAUL, J. (2006): Facies analysis and sequence stratigraphy of an evaporitic-fluviatile unit: The Röt Röt 1 (Lower Triassic, ). – N. Jb. Geol. Paläont., Abh., 242 (1): 103–132, 12 fig.; Stuttgart.