Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre

A description and classifi cation of the successions of the new scientifi c core drillings at Heidelberg is presented. Since 2002 drilling and research activities were ongoing in the Heidelberg Basin (HDB), as a mid-continental sedimentary archive within the Upper Rhine Graben (URG), Germany. The HDB is supposed to host one of the longest continuous successions of Quaternary sediments in Europe, due to continuous subsidence of the basin and sediment input from various sources. The HDB is about half-way between the Alpine source area of the Rhine and the North Sea. Here the Quaternary input is least affected by discontinuities due to climate events as alpine glacier meltdown events or periods of low sea level. Reversely, the low infl uence of climate leads to a larger tectonic control. The sedimentary succession of more than 500 m is considered as primarily controlled by tectonics, but with incorporated climate signals. For classifi cation purposes, sediment provenance, lithofacies-associations, and the ratio of accommodation space and sediment input are used. Some biostratigraphic markers are also available. We suggest a sedimentary scenario where the overall fl uvial environment is twice interrupted by lacustrine intervals. The accommodation space varies too: in one period it expands even beyond the eastern boundary fault of the HDB. [Mächtige Abfolge quartärer Sedimente im Depozentrum des Heidelberger Beckens] Kurzfassung: Die neue Forschungs-Kernbohrung aus Heidelberg wird beschrieben und gegliedert. Die Forschungsund Bohraktivitäten im Heidelberger Becken (HDB) begannen im Jahr 2002; sie erschließen ein kontinentales Sedimentarchiv im Oberrheingraben (URG). Im HDB wird eine der längsten Sedimentabfolgen quartärer Sedimente in Europa erwartet, dank kontinuierlicher Subsidenz des Beckens in Verbindung mit kontinuierlichem Input von Sedimenten unterschiedlicher Herkunft. Das HDB befi ndet sich auf halber Strecke zwischen dem alpinen Einzugsgebiet des Rheins und seiner Mündung in die Nordsee. Eine kontinuierliche Sedimentation ist hier eher möglich als am Alpenrand mit seinen Schmelzwasser-Erosionsereignissen oder an der Küste mit ihren Meeresspiegelschwankungen. Dieser eher geringe Einfl uss des Klimas hat zur Folge, dass die Tektonik eine umso größere Rolle bei der Steuerung der Sedimentation spielt. Die über 500 m mächtige quartäre Abfolge ist daher in erster Linie durch Tektonik kontrolliert, wobei Klimasignale ebenfalls Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre DIETRICH ELLWANGER, GERALD GABRIEL, THEO SIMON, ULRIKE WIELANDT-SCHUSTER, REINHARD O. GREILING, EVA-MARIE HAGEDORN, JÜRGEN HAHNE & JÜRGEN HEINZ *) *Addresses of authors: D. Ellwanger, Regierungspräsidium Freiburg, Abteilung 9 (Landesamt für Geologie, Rohstoffe und Bergbau), Albertstraße 5, 79104 Freiburg i. Br., Germany. E-Mail: dietrich.ellwanger@ rpf.bwl.de; G. Gabriel, Leibniz Institute for Applied Geophysics, Stilleweg 2, 30655 Hannover, Germany. E-Mail: gerald.gabriel@liag-hannover.de; T. Simon, Regierungspräsidium Freiburg, Abteilung 9 (Landesamt für Geologie, Rohstoffe und Bergbau), Albertstraße 5, 79104 Freiburg i. Br., Germany. E-Mail: theo.simon@rpf.bwl.de; U. Wielandt-Schuster, Regierungspräsidium Freiburg, Abteilung 9 (Landesamt für Geologie, Rohstoffe und Bergbau), Albertstraße 5, 79104 Freiburg i. Br., Germany. E-Mail: ulrike.wielandtschuster@rpf.bwl.de; R. Greiling, Geologisches Institut Strukturgeologie und Tektonophysik, Universität Karlsruhe (TH), Hertzstr. 16, 76187 Karlsruhe, Germany. E-Mail: er8@agk.uka.de, E.-M. Hagedorn, Leineweberstr. 9, 51381 Leverkusen, Germany. E-Mail: eva.hagedorn@gmx.de; J. Hahne, Tiefental 3, 37586 Dassel; Germany. E-Mail: juergenhahne@gmx.de; J. Heinz, Hydroisotop GmbH, Karl-Friedrich-Str. 19, 79312 Emmendingen; Germany. E-Mail: bw@hydroisotop.de Eiszeitalter und Gegenwart Quaternary Science Journal 57/3–4 316–337 Hannover 2008


Introduction
This paper summarises fi rst results and impressions of the newly cored research borehole at Heidelberg.It is located at the depocentre of the "Heidelberg Basin" (HDB), close to the eastern margin of the northern Upper Rhine Graben (URG).The probably largest and most complete Quaternary sediment succession along the Rhine has been exhibited, amounting to > 500 m.It proved to be a fairly continuous continental archive of the Quaternary in superposition and quite good resolution.The sediments are strongly infl uenced by the input of the river Neckar, a major tributary of the Rhine which has its outlet into the URG within Heidelberg.Two other boreholes representing other parts of the HDB are the borehole of Viernheim in the geographic centre of the basin (HOSELMANN 2008), and the borehole of Ludwigshafen at the western margin (WEIDEN-FELLER & KÄRCHER 2008, ROLF, HAMBACH & WEIDENFELLER 2008; Fig. 1).Their sediments are both dominated by input of the Rhine.All three boreholes are part of a multidisciplinary research project (The Heidelberg Basin Drilling Project;ELLWANGER et al. 2005, 2007, GABRIEL et al. 2008).Its aims will be to identify the interaction of climate and tectonics as controlling mechanisms of sedimentation, describe properties and 3D architecture of the infi ll, and contribute to the correlation of alpine and north European Quaternary stratigraphy.This paper only contributes to the basics of this research, as is it primarily focused on the Heidelberg borehole.

Regional geological context
The northern URG contains a more or less continuous succession of Oligocene, Neogene and Quaternary sediments, which accumulated due to ongoing subsidence since Oligocene time (DÈZES, SCHMID & ZIEGLER 2004, DURINGER 1988, GIDEON, LOPES CARDOZO & BEHRMANN 2006, ROTSTEIN et al. 2006, SCHUMACHER 2002, ZIEGLER 1992).In the Quaternary, the subsidence increased towards the east, which led to a halfgraben architecture with a maximum sediment thickness at the eastern margin of the URG, i.e. the Heidelberg deep (Heidelberger Loch, location of the Heidelberg borehole, BARTZ 1974).The western part of the Graben is slightly uplifted.As a result, the HDB lowlands are bordered in the east by the Odenwald highlands and the Kraichgau depression.West of the HDB, there is a widespread foothill landscape within the URG (PETERS 2007), and the Pfälzerwald highlands at the western URG shoulder (Fig. 1).The subsidence of the HDB is balanced by sediment input throughout the Quaternary.The primary sediment sources are the fl uvial systems of Rhine and Neckar.The deposits mainly refl ect this fl uvial environment, but also include intervals dominated by local coarse debris input from the nearby highlands, and also some lacustrine intervals.The HDB succession is, therefore, not only an archive of the Quaternary stratigraphic evolution, but also of the varying sedimentary dynamics.

Definition of "Quaternary" in the Upper Rhine Graben (URG)
Some popular stratigraphic schemes of the URG are diffi cult for stratigraphers to apply, as chronostratigraphic terms are used to describe lithostratigraphic units (Table 1 in GABRIEL et al. 2008).In this routine, "Quaternary" and "Pliocene" are defi ned by their sediment provenance (e.g.BARTZ 1982, HGK Rhein-Neckar 1999).I.e."Pleistocene" Rhine sediments enclose material of alpine origin, "Pliocene" sediments don't.This refers to a major event in the history of the alpine Rhine, when its course changed from "circumalpine" towards the North Sea (VILLINGER 1998).
In the URG, this provenance transition is usually a very distinct and widely recognized boundary.The alpine origin of the sediments above is easely detectable by carbonate content and identifi cation of pebbles of alpine origin.It can further be proved by heavy mineral analysis (BOENIGK 1987, HAGEDORN 2004).According to the few yet available chronostratigraphic markers, the boundary is considered diachronic.NIGK 1970, 1987, BOENIGK & FRECHEN 2006, KEMNA 2008, KEMNA & WESTERHOFF 2007, WESTERHOFF 2004, 2008).
In this paper we use the lithostratigraphic scheme outlined below (chapter 3.3), which has been created some years ago to avoid confusion.We also use chronostratigraphic terms, but only when referring to chronostratigraphy and only based on chronostratigraphic data.

Sediment evaluation
In Applied Geology, the Quaternary sediment succession of the URG is up to now described as an alternation of units of coarse and fi negrained sediments (Kieslager, Zwischenhorizonte, BARTZ 1982).These units are widely used in e.g. in hydrogeology, serving as aquifer resp.aquitard units.Most data in archives fi t in this routine.
In this paper we describe the succession as lithofacies resp.lithofacies associations and identify genetic units (FIEBIG 1999).We attempt to give a fi rst interpretation of sedimentary cycles of various orders, stacking patterns and sedimentary control in different environments.
Dealing with borehole cores of often quite coarse grained sediments, this is based primarily on fi rst analysis of grain sizes, stratifi cation, petrography, heavy minerals, carbonate content, pollen, molluscs, ichnofossils etc.Studies on stratifi cation and textures are limited due to weak consolidation of the material.We distinguish gravel, sand and fi nes (silt and clay) according to DIN 4022 and lithofacies terms according to MIALL (1985MIALL ( , 1996)).The succession is related to trends of the relative base level and the sediment input (a/s-ratio).They again depend on what is considered to ultimately control the sedimentary system: tectonic uplift and subsidence, compaction, but also effects of climate as intensifi ed mechanical erosion.
The base level concept as applied here goes back to basic studies of CROSS et al. (1993) and of CROSS & LESSENGER (1998).They combine WALTHER's law with sediment volume partitioning.This leads to a simplifi ed way to regard sedimentary cycles as a function of accommodation space vs. sediment supply (a/s-ratio).In particular the grain size variations and changes in the recorded environment are interpreted, e.g.sequences with dominant pedogenesis represent very low input and high accommodation space, i.e. high a/s-ratio; in contrast to sequences with dominant sand preservation in the fl uvial system where the fi nes are reworked, i.e. low a/s-ratio.The changes of increase and Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre decrease of the a/s-ratio are then used to identify the sequence stratigraphic frame which can be used for correlation.

Lithostratigraphy
The sedimentary succession is put in the frame of several lithostratigraphic units which were lately defi ned as formations and sub-formations (Fm, Sfm, SYMBOLSCHLÜSSEL GEOLOGIE BADEN-WÜRTTEMBERG 2007).

Some general remarks
The Heidelberg research boreholes are the deepest in the project, representing the depocentre on the eastern margin of the HDB.They are located just north of the Campus of Heidelberg University, still close to the mouth of the River Neckar in downtown Heidelberg, and situated on the alluvial fan of the Neckar.For technical reasons, a fi rst borehole was cored to 190 m, a second borehole from 184 to 500 m (UniNord 1+2).The two sites are only 300 m apart and are easily correlated (Fig. 2).Their combined depth of 500 m exhibits Quaternary sediments down to ~ 500 m which is more than originally predicted (before drilling the chronostratigraphic Plio-Pleistocene transition was expected around 400 m, i.e. we intended to recover 400 m cores of Quaternary sediments, plus 100 m of Pliocene sediments).We present a condensed lithostratigraphic description and classifi cation of the sediments, including some remarks on • sediment provenance, derived from pebble and heavy minerals analysis; • the sedimentary environment; • the few already available biostratigraphic markers, derived from pollen analysis, that are used to set up a chronostratigraphic frame; • and depositional trends.Following the conventional technique of core documentation, the major units are in order from top to bottom; but subunits in upward direction.A detailed description including further data will be published later in a special volume of LGRB Informationen (Regierungspräsidium Freiburg, www.rp-freiburg.de).The sediment succession is provisionally subdivided in three large units according to the above lithostratigraphic terms.At UniNord they were identifi ed as follows: • Mannheim-Formation from 56 to 0 m; as a series dominated by coarse gravels, with layers of diamicton and fi nes, including a well preserved fossil soil; DIETRICH ELLWANGER ET AL.
• Boundary: abrupt transition of fi ne-coarse sedimentation • Kurpfalz-Formation from 299 to 56 m; as a series with coarse debris at the basis (subunit K1); a two-parted main section with coarse debris and gravel, sand and fi nes in the middle part; and a fi ne sediment dominated section on top; • Boundary: change of provenance and abrupt transition of fi ne-coarse sedimentation • Iffezheim-Formation from >500 to 299 m; as a cyclic alternation of white-sand to clay and dark sand, altogether of non-alpine origin.

Mannheim Formation at UniNord
The Mannheim-Formation at UniNord covers the interval from 0 to 56 m.The sediments are composed of about 75 % coarse debris and gravel, 10 % sand, 5 % fi nes, and 10 % diamicton.Fluvial gravels dominate.However, the succession begins and ends with a layer of coarse debris, the upper one resembling the alluvial fan of the Neckar which presently undergoes erosion and terrace formation.Within the gravels there are insertions dominated by diamicton; one of them grading into fi nes with a fossil soil.
The succession is stratifi ed as follows (cf.DIETRICH ELLWANGER ET AL. Sedimentation: The depocentre of the HDB corresponds with the alluvial fan of the Neckar.The genetic units in intervals with coarse debris and fl uvial gravels match well with this proximal setting (Fig. 3).One major interval with diamicton, fi nes and pedogenesis, occurs all over the depocentre (HGK 1999).As a result, the Mannheim-Fm shows an overall coarse -fi ne -coarse trend, going along with a fi rst increasing then decreasing a/s-ratio.Summary and interpretation: The major part of the Mannheim-Formation at the Heidelberg UniNord borehole is built up by coarse sediments representing the proximal lithofacies of the Neckar alluvial fan.This is an inputcontrolled system which strongly depends on sediment supply from the nearby Odenwald highlands.As preservation in superposition is discontinuous, due to lateral shifting within the fan, the subsidence of the basin plays only a minor part.

Kurpfalz Formation at UniNord
The Kurpfalz-Formation at UniNord covers the interval from 299 to 56 m, i.e. its thickness amounts to 243 m.It is composed of 35 % debris and gravel, 20 % sand, and 45 % fi nes.
There is a continuous background supply and preservation of fi ne sediments (lacustrine, fl uvial overbanks), interrupted by three major intervals with coarse debris and gravel input (fl uvial bedload, mass fl ow).Accordingly it is subdivided into lithostratigraphic subunits.Odenwald (mainly Buntsandstein, some crystalline and Muschelkalk).The sediments of the Ladenburg-Subformation belong primarily to the "fi nes and sands of Neckar or local origin".There are exceptions at the top of two lacustrine intervals, where minor sand pulses of Rhine origin are identifi ed by their instable heavy mineral content.Presently we interpret this to be fl uvially reworked eolian input.-The Ladenburg-deposits of UniNord are contemporaneous with similar deposits all over the HDB which are usually of Rhine origin.They also correlate with the upstream buried valley infi ll at the discovery site of the Homo heidelbergensis located near to the village of Mauer, some 15 km southeast of UniNord (LÖSCHER 1996).From this it follows that the sediment of this subunit covered the whole HDB, and extended beyond the Eastern Boundary Fault (EBF) of the URG.I.e. the nearby Neckar valley within the Odenwald highlands is also, as a drowned valley, part of the basin.The subunits K1 and the lower part of K3 show strong evidence of periodical fl uvial input from the alpine Rhine, with continuous input from the Neckar upheld.In K1, the arrival of the Rhine and the preservation of fi nes even when alternating with coarse local sediments indicate a strongly increasing a/s-ratio.In K2, only sand on fi nes of non-Rhine origin are yet identifi ed.The K3 succession begins with an alternation of local and Rhine input.Then the local input is gradually replaced by supply from the Neckar, and still further up the input from the Rhine terminates.From 190 m upwards only sediments of Neckar provenance are left.The three intervals of coarse debris and gravel (subunits K1 and K3) refer to expanding erosion into the Odenwald, probably due to uplift.

Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre
There is always an overall dominance of coarse Buntsandstein, but the ratio of the supplementary components varies (Muschelkalk, crystalline).The fi rst coarse pulse (299 -297 m, basis of K1) contains much local crystalline (Heidelberg Granite).The main pulse (287 -263 m) is mainly Buntsandstein, but with an upward increasing ratio of Muschelkalk; i.e. the sediment source is fi rst "downtown Heidelberg", then expanding towards the Muschelkalk scarp.
-Two coarse intervals of fl uvial gravels follow (206 -189 m and 168 -126 m, subunit K3).Within the latter a fi rst small then increasing ratio of Jurassic is present, and there are some layers where the Muschelkalk components dominate.This is also characteristic regarding some correlative gravely insertions in the succession of the Viernheim sister drilling (interval 180 to 80 m, HOSELMANN 2008).
Sedimentation: The overall fl uvial evolution of the UniNord succession is interrupted in the Kurpfalz-Formation by intervals of lacustrine conditions and by intervals of strong supply of mass fl ows.Our interpretation as a lacustrine environment is based upon the abrupt occurance of coarse-grained debris fl ows within the fi ne-grained background sedimentation.In some parts of the succession, even matrix supported mass fl ow deposits including boulders and cobbles occur (high density mass fl ows).The abrupt alternation of mass fl ow-and background-sedimentation is a clear indication for lacustrine deposition in a lake system with a minimal water depth of several meters.The fi rst lacustrine interval is at the basis of the Formation where mass fl ow deposits of coarse debris are embedded in fi nes, with almost no transition (subunit K1).It carries on in subunit K2 with few coarse layers in the fi nes.Eventually the lacustrine sedimentation terminates, fi rst indicated by fossil soils in the fi nes (transition of subunits K2 to K3), then by cycles of fl uvial gravels to fi nes (subunit K3).The lower gravel seems to represent a local event; the upper refl ects a long and overall coarsening-up series of a prograding fl uvial system.-The transition to follow, from fl uvial gravels to the fi nes of the Ladenburg-Subformation, is again very abrupt.The fi nes are massive; again with insertions of mass fl ow deposits (here the components are well rounded i.e. reworked from the gravels).This again represents a lacustrine environment.Towards the top of these fi nes, the environment migrates back towards fl uvial, fi rst visible in traces of plant roots and ichnofossils, still within the fi nes, then by re-establishing the prograding fl uvial system (lacustrine-to-fl uvial cycle from 126 to 89 m = 37 m).In the upper part of the Ladenburg-Subformation, two more lacustrine to fl uvial transitions are identifi ed (89 -74 m = 15 m; and 74 -56 m = 18 m).They range from massive fi nes up to graded sands, i.e. they comprise no gravely sediments.Further up, the lacustrine to fl uvial cyclicity is drowned by the input of the Mannheim-Formation.The Kurpfalz-Formation shows an overall decreasing a/s-ratio throughout the succession, with various symmetrical and asymmetrical cycles of lower order (Fig. 4).The maximum accommodation space is given in the fi rst lacustrine cycle (K1, K2), which hosts not only coarse local debris but also alpine sands of the Rhine.The alpine infl uence is then pushed back by prograding coarse-grained fl uvial Neckar deposits (K3).
Chronostratigraphy: Some biostratigraphic markers based on pollen analysis are already available.They are preliminarily interpreted.
At Summary and interpretation of the Kurpfalz-Formation: The succession of the Kurpfalz-Formation at UniNord, within its upper "sequence"boundary and its lower "provenance"-boundary, comprises one overall large scale cycle, from a basal lacustrine environment up to a large and input controlled subunit of prograding fl uvial gravels.The fi nes to follow are, although in parts lacustrine and related to a fi nal pulse of subsidence, only of local importance.We suggest this has to do with the pattern of Rhine sediments through time in the HDB.This is confi rmed by the sister boreholes of the Heidelberg project at Ludwigshafen and Viernheim, where, as it seems, the Rhine signal comes, in each case, at a different chronostratigraphic level.HOSELMANN 2008, KNIPPING 2002, 2008).
As discussed above we suggest correlating a subunit of prograding gravels from Heidelberg (Bavelian) with the 80 -180 m interval at Viernheim.This leaves 40 m with little evidence of any greater hiatus.From all this we suggest the provenance change to happen in the Waalian.The above may be interpreted as "alpine" Rhine sediments migrating in three steps through what later became the HDB: This story begins in Ludwigshafen close to the Pliocene-Pleistocene transition; then it continues in Heidelberg in the Eburonian; and fi nally comes to Viernheim in the Waalian.The subunit of prograding gravels (K3, Bavelian) appears to be the fi rst unit covering the HDB in its present extent as a whole, as do the above units of the Ladenburg-Subformation and the Mannheim-Formation.Below the gravels (K3) there is a patchwork of local units which are diffi cult to correlate.Here the units including alpine Rhine sediments may be of small extend.Their west-to-east migration (from Ludwigshafen to Heidelberg) seems to be subsidence-controlled, as a result of the Halfgraben architecture.Their return back west to Viernheim is related to Neckar input.The upper units covering the entire HDB are related to input pulses of Rhine and Neckar which include potentially increased sediment volumes during the Pleistocene glaciations.All sediments below the "alpine" Rhine, regardless of their chronostratigraphic position, are not part of the Kurpfalz-Formation.They belong, to the Iffezheim-Formation.

Iffezheim Formation at UniNord
The Iffezheim-Formation at UniNord covers the interval from >500 to 299 m, i.e. >202 m.It is a cyclic alternation of fl uvial deposits with an average composition of 55 % sand, and 45 % fi nes.The succession is subdivided in several lithostratigraphic subunits, according to lithofacies variations.They are dominated by sand at 316 to 382 m (I5); by fi ne sediments at 382 to 411 m (I4); again by sand at 411 to 452 m (I3); fi ne sediments at 452 to 467 (I2); and fi nally by sand at 467 to >500 m (I1).The uppermost subunit at 299 to 316 m (I6) resembles the transition to the lacustrine environment and to the onset of coarse local debris of subunit (K1).The main fl uvial lithofacies are: • Grey, coarse to medium-grained sands.
They contain only few gravely components, the small pebbles being well rounded and often with weathering halos.Quite frequently there are other coarse components, Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre as pieces of wood of various size (in the cores with diameters up to 25 cm), but also reworked pieces of fi ne sediment, ranging from small rounded pieces up to large strata.Their original stratifi cation may be preserved, including organic-rich laminae or even peat.They were probably in a frozen state during transport.• White, fi ne to medium-grained sands, usually very well sorted.They either alternate with the grey sand lithofacies, or grade into green silt with sandy laminations, and finally into the silt and clay cycles.• Clay-rich overbank fi nes, forming sequences of green and sandy silt grading into clay-rich silt up to almost pure clay, usually speckled with brownish (wet) and reddish (dry) colours resembling pedogenesis.Colours are intense, apart from the transition to the Kurpfalz-Formation where they become dark and gloomy.
The sequences are rich in ichnofossils, in some layers also in authigenic grains (authigenic siderite, Dr. Martin, Freiburg).Some are fractured due to diagenetic compaction.
The sediment succession of the Iffezheim-Formation is stratifi ed as follows (cf.Fig. 5  Provenance: The "local" i.e. non-alpine origin of the sediments determines their allocation to the Iffezheim-Formation.This is primarily based on heavy mineral analysis.Many of the few coarser components are of Buntsandstein origin, as are several layers of red sands.-The provenance of the other sediments remains uncertain.The well sorted white sands are probably far transported, but this may be an inherited feature if they are reworked from nearby Neogene sands.The grey sands are related to various sources, including crystalline and Buntsandstein (Odenwald?Black Forest?).They seem confi ned to a fl uvial system close to the eastern margin of the URG.The source of the silt and clay is again undetermined, probably nearby Neogene.
Sedimentation: By alternation of the grey sand lithofacies and the silt-to-clay lithofacies, several genetic units are stacked to symmetrical cycles of increasing and decreasing a/s-ratios.Within the fi nes, the turning points often coincide with intensive pedogenesis i.e. almost no input; within the sands they coincide with sections where large pieces of reworked fi nes indicate a/s minima.These bedload-dominated units represent the greater part of the succession.The preserved cycles are in the 10 to 50 m order.-The minima of accommodation space are likely to be related with increasing sediment supply, maybe due increased sediment volumes as a result of colder climate (some of the reworked fi nes are still stratifi ed, they may have been frozen when redeposited).As opposed to this the sediment input is generally much reduced in silt-clay sections, with ichnofossils and traces of more or less reworked fossil soils.Preservation is primarily related to local subsidence of the depocentre, but differentiated uplift within and at the northern margin of the URG may also be involved.
Chronostratigraphy: Some biostratigraphic markers based on pollen analysis are already available.There are no hints for in-situ sediments from the Pretiglian or Reuverian period.
The reworked sample at 358 m illustrates the pollen spectra to be expected from insitu Reuverian.
Summary and interpretation of the cored part of the Iffezheim-Formation: According to the definition outlined above, the succession is not infl uenced by instable heavy minerals of the alpine Rhine.The above pollen markers show that the succession terminates well above the base of the Quaternary, i.e. in a time slice when the course of the alpine Rhine was already bound within the URG (in the western HDB proved by WEI-DENFELLER & KNIPPING 2008).At the same time, maximum sedimentation rates occur on the eastern side at Heidelberg UniNord.All this requires a two-partition of the HDB, with a western basin hosting the alpine Rhine, and an eastern basin with maximum sedimentation rates.The transition between the basins is suggested to be represented by the Viernheim drilling where the Rhine sediments arrived latest.

Below 500 m
As the cored UniNord boreholes end at 500 m still within the Tiglian, the lower part of the Tiglian, the Pretiglian, and the transition into the uppermost Neogene unit i.e. the Reuverian remain uncored.In order to estimate compaction and tectonic subsidence rates, serving as accomodation space of the cored units, some basic informations on the deeper subsurface are introduced here.2002, OGG, OGG & GRADSTEIN 2008).They serve as a geochronologic frame to estimate average sedimentation rates for the units (Tab.2, Fig. 6).They are, as yet, uncorrected, but may be used to calculate the non-tectonic i.e. compaction part of the subsidence.

Input and uplift
The local aspect: The relatively rapid increase of sediment thickness during Eburonian time is associated with coarse, clastic deposits.Clastic fragments are derived from Triassic sedimentary rocks and the Heidelberg granite and associated crystalline rocks of the Variscan basement.This sediment composition is interpreted to refl ect the synchronous uplift of the adjacent rift shoulder and the initiation or reactivation of faults in the Heidelberg town area, which trend both subparallel with and at a high angle to the major, eastern rift bounding fault.Activities at these faults led to the exposition of the crystal-  1. Cf. Fig. 6.Control of the subsidence: We suggest tectonic control only if the sedimentary environment relies on tectonic subsidence.This is, presently, only the case in the lacustrine intervals covering small areas in the Heidelberg deep (Eburonian, Cromerian).In all other cases we suggest that considerable parts of the accomodation space come up from compaction of underlying fi ne sediments.This will be considered in future studies, including correction of the sedimentation rates.
-The discussion of the potential tectonic control of the input remains unaffected.
Tab at the basal Mannheim-Formation (post-Cromerian, ~ 0.5 Ma).Both refl ect uplift periods of the Odenwald.The post-Cromerian uplift is contemporaneous with the main uplift of the Rhenish Massif (cf.various studies of the lower main terrace e.g.HOSELMANN 1994).
All this leads to a scenario of Quaternary uplift = input events in cycles of ~1 Ma, proceeding from south to north: ~0.5 Ma Rhenish Massif plus Odenwald (?plus Black Forest); ~1.7 Ma Odenwald (?plus Black Forest); ~2.6 Ma southern Black Forest.Each uplift event potentially provides sediment supply which will more easily be activated if the mechanical erosion is facilitated by climate changes (e.g.VANDENBERGHE 1993, 1995, BUSS-CHERS 2007).In case of the middle input event the Tiglian to Eburonian transition is proved to occur well below the coarse input is recorded.This supports the above scenario.The other events lack of chronostratigraphic data.

Outlook
The descriptions, basic data and correlative patterns presented here are all focused upon the specifi c situation of the Heidelberg deep i.e. the cores of the borehole of the UniNord location in Heidelberg.In the interpretative steps to follow, the controlling parameters of sedimentation will have to be more thoroughly identifi ed, DIETRICH ELLWANGER ET AL.  e.g. are increasing a/s-ratios due to tectonic subsidence or to compaction within the basin, or due to uplift around the basin.This can only be accomplished if the entire HDB is regarded.Additional boreholes (e.g.HAIMBERGER, HOPPE & SCHÄFER 2005, WIRSING et al. 2007, HOSEL-MANN 2008, HUNZE & WONIK 2008, SIMON 2008, WEIDENFELLER & KNIPPING 2008) as well as seismic and logging data (BUNESS, GABRIEL & ELLWANGER 2008) will have to be included

Acknowledgement
The Heidelberg drilling project was greatly supported from many people and institutions.In fi rst place the actual and former heads of the involved institutions, Prof. Dr. U. Yaramanci, Prof. Dr. H.-J. Kümpel, Prof. Dr. R. Watzel, Ltd.Bergdirektor V. Dennert and Prof. Dr. B. Stribrny.Dr. E. Würzner, Lord Major of the city of Heidelberg, arranged contacts, whenever necessary.The involved members of staff of the Stadtverwaltung Heidelberg, the Universitätsbauamt Heidelberg and the Amt für Vermögen und Bau Baden-Württemberg, Mannheim gave logistic support, provided the pieces of land for the Heidelberg boreholes and friendly helped whenever they could.All this support is gratefully acknowledged.Scientifi c discussions with colleagues helped signifi cantly to become more familiar with several topics related to this project.Thanks to Dr. H. Buness, Dr. W. Engesser, Prof. Dr. M. Frechen, Dr. F. Fromm, Dr. C. Hoselmann, Dr. M. Martin, H. Meyer, Dr. Ch. Rolf, R. Thienel, Dr. M. Weidenfeller, Dr. T. Wonik and K. Worm.We very much thank Prof. Dr. Fiebig and an anonymous colleague for their reviews and additional valuable comments.

Fig. 1 :
Fig. 1: Location of the UniNord boreholes in Heidelberg and other boreholes.The Eastern Boundary Fault (EBF) of the Upper Rhine Graben (URG) separates the lowland plains of the Upper Rhine from the adjacent highlands.The Heidelberg Basin (HDB) covers approximately the area between the present River Rhine and the EBF, extending some 10 -15 km north and south of Heidelberg.The highlands east of the EBF are twoparted, the Odenwald anticline (highlands) in the north, and the Kraichgau syncline (lowlands) in the south.The Neckar valley is incised into the southern Odenwald highlands, as is the buried early Neckar valley at Mauer.

Fig
petrographic spectra of the gravels refl ect the up-river catchment of the present Neckar valley passing through the Odenwald highlands.There are large components of the nearby Buntsandstein which are coarse and poorly rounded.The Muschelkalk components are usually fi ner and better rounded; however, one boulder occurs at the basis of the unit at 56 m.Some small components come from the far distant Neckar catchment, i.e. the Jurassic of the Swabian Alb.The crystalline basement with the nearby major exposure below Heidelberg castle is only poorly represented.-Most sand and fi nes are also of Neckar provenance, with the exception of several sand-rich strata resembling traces of Rhenish provenance by their instable heavy mineral composition.They are very well sorted and therefore supposed to come from reworked eolian input, alike to the nearby dunes, and may represent elder phases of cold climate (26 -29 m).

Fig 2 :
Fig 2: Overview of the sediment succession of the Heidelberg deep down to 500 m, comprised from the UniNord boreholes of 2006 (interval from 0 to 190 m) and of 2008 (interval from 184 m to 500 m).Lithostratigraphic frame, major lithologies and sedimentary environments.Legend cf.Fig. 3.
• In Heidelberg, the overall depocentre of the HDB, the Rhine signal begins at 299 m (Eburonian) and ends at 190 m (Waalian); • In Ludwigshafen at the western margin of the HDB, the Rhine signal begins at 177 m close to the Pliocene-Pleistocene transition (WEIDENFELLER & KÄRCHER 2008 and WEI-DENFELLER & KNIPPING 2008), then comes to a standstill (increase of local sediments with only stable heavy minerals) at 137 -127 m and 109 -97 m (Waalian); • In Viernheim at the geographic centre of the HDB, the Rhine signal begins at 220 m (

4 The Heidelberg Cores -Description and basic classifications (Litho-and Biostratigraphy)
Any further interpretation needs a chronostratigraphic frame.
Chronostratigraphy: No chronostratigraphic markers are yet available.As the underlying unit (Ladenburg-Subformation) is supposed to date from the Cromerian, post-Cromerian ages are expected.The fossil soil at 34 m is quite well preserved, dividing the succession into an upper and a lower part.Their interpretation remains open (last and penultimate glaciation, effects of loading and compaction).
They are preliminarily interpreted.

Table 1 :
Long sequence of Quaternary Rocks in the Heidelberg Basin Depocentre Lithostratigraphy and Chronostratigraphy of the sediment succession of the borehole Heidelberg UniNord.The lithostratigraphic boundaries are controlled by tectonics (cf.Tab.2); the chronostratigraphic stages refer to the alpine and north European glaciations and to the pollen-based biostratigraphy of NW-Europe.Sediment thicknesses are uncorrected.