Soil Conditions, Soil Carbonates and Former Vegetation in the Geul Valley from Gulpen to Meerssen (South Limburg, the Netherlands)
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551.31:551.311.2:552.54(492.945) MEDEDELINGEN LANDBOUWHOGESCHOOL WAGENINGEN • NEDERLAND • 80-8(1980) SOIL CONDITIONS, SOIL CARBONATES AND FORMER VEGETATION IN THE GEUL VALLEY FROM GULPEN TO MEERSSEN (SOUTH LIMBURG, THE NETHERLANDS) W.VA N DE WESTERINGH etal. Departmentof Soil Science andGeology, Agricultural University, Wageningen, The Netherlands (received3-IV-80 ) H.VEENMA N & ZONEN B.V.-WAGENINGEN-1980 iüOL '•:.,:i TT CONTENTS 1. PREFACE 2. W. VAN DE WESTERINGH. Soils and their geology in the Geul valley 1 Summary 20 Samenvatting 21 3. R. MIEDEMA. Incidence and distribution ofcarbonate s inth esoil so f the meandering river Geul 27 Summary 43 Samenvatting 44 4. A. J. HAVINGA and R. M. VAN DEN BERG VAN SAPAROEA. Former vegetation and sedimentation in the Geul valley 47 Summary 58 Samenvatting 58 ACKNOWLEDGEMENTS 60 PREFACE During fiveyear s(1974-78 )a soi lsurve ywa sundertake n byth e Department ofSoi lScienc ean dGeolog yo fth eAgricultura lUniversit yo fWageninge ni nth e valley of the river Geul between Gulpen and Meerssen (South Limburg, The Netherlands).Th emai npurpos ewa st ointroduc eundergraduat estudent st osoi l surveypractice .Th ewor kconsiste d insurveying ,describin gan dmappin gsoils , making cross-sections and estimating the fluctuation of the water table with reference to soilcharacteristics . The results form a sound basis for a better understanding of the geology and soils in the Geul valley. Because of the very detailed field work (boring density 25 x 50m ornarrower) , much more information wasobtaine d than in thecas eo fa norma lsoi lsurvey .T ocomplet eth esurve ysom especia lstudie san d laboratory research were undertaken by the authors in co-operation with graduate students.Th e results are presented in the following three papers. Thefirst pape routline sth eHolocen estratigraph y ofth evalle yfill i nrelatio n to soil conditions. Five sedimentation stages have been distinguished which determined thesoils .Henc e thelegen d of thesoi lma p hasa marke d geological character.Th esoi lpatter nreflect s theyounge rsedimentatio n historyo fa smal l river,tha t occupies afairl y narrow valley. Theincidenc ean dpatter n ofdistributio n ofcarbonate s showsmarke d differ encesbetwee nth evariou ssoils .Ver ydetaile dfield studie swer eundertake nt oex plain the relationship between the presence of carbonates, the sedimentation regimeo f the river Geul, time-dependent decalcification and to the occurrence of fans along the valley border. The results of this investigation are given in thesecon d paper. During the soil survey it was assumed that a relationship exists between former sedimentation in the valley and former agricultural practices (deforest ation) in the surrounding upland, as the texture of the valley soils is often similar to that of the upland loess soils. Extensive and often thick colluvial deposits along the valley borders are evidence of another effect of human ac tivity. To obtain some insight into the age of the fluvial and colluvial deposits and theirrelationshi pt oagricultura l history,tw osoi lprofile s wereinvestigate d bymean s ofpolle n analysis.Th eresult sar e setou t inth e third paper. SOILS AND THEIR GEOLOGY IN THE GEUL VALLEY W.va n deWestering h CONTENTS 1. INTRODUCTION 1 2. GEOLOGY 4 2.1 Stage I 4 2.2 Stage II 4 2.3 Stage III 6 2.4 Stage IV 7 2.5 Stage V 8 3. SOIL CONDITION 9 3.1 Soils 9 3.2 Calcareous material 10 3.3 Hydrology 10 3.4 Soil map legend 11 3.5 Soil map 12 3.6Fan s 17 4. THE PRESENT LANDSCAPE 18 5. SUMMARY 20 6. SAMENVATTING 21 7. REFERENCES 24 1. INTRODUCTION Therive rGeu risesl nea rEynatte n inBelgium .I tenter sTh eNetherland snea r Cottessenan dflows int oth eMeus enea rBunde .B ythe ni tha scovere dabou t5 6 km, two-thirds of this distance being in The Netherlands (Fig. 1). From the Dutch-Belgian frontier to Mechelen it flows in a south-north direction, from Mechelent oSchi no pGeu li trun snorth-wes t andfro m Schino pGeu lt oBund e in a more westerly direction. It receives many small tributaries. Together they form an essential part ofth epleasan t South Limburg landscape (Fig.2) . By Dutch standards the Geul is a fast flowing river. The slope varies from about 7.62m/k m near Epen to 1.33m/k m near Houthem. Theaverag ei sabou t 3m/km . Itsdischarg e isver yirregular . Near Meerssen theaverag edischarg ei s Meded. Landbouwhogeschool Wageningen 80-8(1980) 1 K.j- /^""de / X boundary of HEERLEN vïf / s. Meerssen ^ ->(the river system # ' Rothem-iÇ^. Vroenhof , ^-_j., (^St.Gerlach / _^ Schaloe n f vauenDurg ^fC-Schin op Geul MAASTRICHT Genhoes/ >.Etenaken _,'' •i GERMANY AKEN BELGIUM \ HENRI-CHAPELLE FIG. 1.Th e river system of the Geul. Meded. Landbouwhogeschool Wageningen 80-8(1980) Meded. Landbouwhogeschool Wageningen 80-8(1980) about 2,3001/ s; th eminimu m discharge inrecen t yearswa s95 01/ s (September 1971),wit ha maximu m of24,2001/ si nOctobe r 1974.I nth ever ywe tperio do f December 1966th edischarg ea tValkenbur g wasabou t 65,0001/s (Information supplied byth e LimburgPubli cWork s Department). Underpresen tcondition s severefloodin g isrelativel yrare .Th elas tfloo d was inth esprin go f1974 . Ona naverag eflood s occurever ytw oyears .Th edischarg e by means ofregulation , hasbee n improved sotha t floods canb eprevente do r theirduratio nshortened .Locall ysmal larea sar emor efrequentl y flooded.Whe n floods occur in the late autumn, winter or early spring, there isusuall y little damage to agriculture, high water levels being generally of short duration. Beforeth emoder nregulatio no fth eGeu lth erive rha da natura lcharacter .Bu ti t should beadde d that for centuries thewate r discharges andlevel s have been influenced byman ,e.g .b ylan dreclamation ,th econstructio n ofwatermills ,etc . The geology and soil conditions of the Geul valley also reflect agricultural practicesi nth eSout h Limburgloes slandscape . 2. GEOLOGY Fivedifferen t stagescoul db edistinguishe di nth ehistor yo fth evalle yfil li nth e Geulbasin .Th efirs t stagei so fpre-Holocen eage ,th eothe r four areHolocene . 2.1. STAGEi (FIG. 3a) Theshap ean dth esiz eo fth eGeu lvalle yindicat ea Pleistocen eorigin .Durin g theformatio n ofth edissecte dplatea u landscapeth evalle yo fth eGeul ,a major tributary of the Meuse, was deepened and widened. As a result of various geological processes thecros s section ofth evalle yha sbecom e asymmetricali n manyplaces ,wit hon estee psid ean don egentl eslope .Smal lterrace-lik eirregula rities areoccasionall yfoun d alongth evalle ywalls .A tth een do fth ePleistocen e the dissected plateau landscape hasbee ncovere d byaeolia nloess . The valley was largely incised inUpper-Cretaceou s limestones. Inth e flood plain ofth epresen t valleysom emetre so fPleistocen e gravelwer elai d downb y braidedriver soverlyin gth eCretaceou smaterial .Holocen esediment shav ebee n deposited onto p ofit .Thes elas t depositsgiv eth evalle yit spresen t character. 2.2. STAGEi i (FIG. 3b) The temperature rose atth ebeginnin g ofth e Holocene andinitiate d anew , more thermophilic type of vegetation (JANSSEN, 1960). This led to a forest vegetation inth e wholeSout h Limburg loessarea . Thenatura l situation ofth e 4 Meded. Landbouwhogeschool Wageningen 80-8(1980) cretaceous limestone a. Stage I. Pleistocene; deposits of a braided river, gravel. aeolian loess |»°e°»| gravel I« ». «I Peat «] clay T fluvial material , '-J fine-silty ffijgffl fluvial material, b. Stage II. Holocene; oldest deposits, tiöiä coarse-silty (loess-like) clay and peat. Ij-.-'.-çj colluvial material \:°'':i (loess-like) I' * *,| fluvial material, sandy c. Stage III. Holocene; increased activity, fine-s1lty deposits. i •i •I r r -r r 'T i •i •i -r d. Stage IV. Holocene; increased activity, e. Stage V. Holocene; coarser-silty deposits. recent deposits, sandy. FIG. 3.Stage si nth efilling o f thevalle yo fth eGeul . Geulvalle yi nwoode dSout hLimbur gwa swette rtha na tpresen ta sa resul to fit s lowelevatio nwit hrespec tt oth esurroundin ghill san dth eoccurrenc eo fspring s along the valley at points where water rises over heavy, impermeable Lower- Cretaceouscla ylayer so rflow si nCretaceou slimestones .Th evegetatio nbecam e a marsh forest (HAVINGAan d VANDE N BERG VAN SAPAROEA,1980) . At the beginning of the Holocene, in such a densely forested landscape, the river mainly carried groundwater base flow that reached the valley through springs and seepages. In a wooded landscape when precipitation exceeds the évapotranspirationth esurplu swate rdoe sno treac hth erive rvi ath esurface ,bu t Meded. Landbouwhogeschool Wageningen80-8 (1980) through the soilan d after deeppercolatio n viath egroundwater . At thisperio d thedifferenc e between base flow and peak dischargeo fth erive rwa sno t great. Asth elandscap ewa scovere db yvegetatio nth esuspende dloa d ofth erive rwa s small.Ther ewa slittl eo rn osedimentation .Onl ysom ecla ywa sdeposited ,o rels e peat was formed. 2.3. STAGEm (FIG. 3C) Aslon ga sth eentir eloes sare awa sunde rpermanen tvegetatio n thedischarg e and activity of the Geul remained more or lessunchanged . It wasonl y slightly affected byclimati cchange si n the Holocene.Th e situation was again changed whenth evegetatio nwa scleare db yma nan dbar esoi lbecam esubjec t toerosion . The first human settlers in South Limburg to clear some parts of the forest wereth e Dutch Bandkeramik people.The ylive do n the boundaries ofth eleve l loessplateaus .The ywer efarmer s andthei rarabl elan dwa so nth eplateaus .Th e coarse-siltyto player so fth eloes ssoil sha da lowe rcla yconten ttha nth efine-silt y subsoils and were weakly acidic.