Landscape system mapping of the humid Baturié massif and its semi-arid piedmont (Northeastern Brazil): A multilayer integration of environmental parameters

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Landscape system mapping of the humid Baturité massif

and its semi-arid piedmont (Northeastern Brazil) :

a multilayer integration of environmental parameter s

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1 . Introduction

The Baturité massif is the erosional remnant of the northwestern shoulder of th e Potiguar rift (Fig. 1), a rift structure formed i n Early Cretaceous times . Present humid bàdimatic conditions on this upstandin g residual Iandform contrast with the semi-ari d conditions of the surrounding plain ('Sertão'). Located -100 km south of Fortaleza (Ceara. NE Brazil). the study area exhibits a characteristic vegetation continuum betwee n evergreen forest('mataatlãntica') of the humid zone and deciduous 'caatinga' of the semi-ari d piedmont via a semi-deciduous forest bell i n the transition zone. Systematic soil successions and Iandlorm variations were also identified through this logo-cimahc framework (Fig 2). The objective of this work was to develop a method of landscape syste m mapping that accounts adequately for these new pedogeo.orphologicaI observations, and that could be applicable to other humid residual massifs of the semi-arid interior o f

Northeastern Brazil .

BGTARO F .'. PLULVAST 1-P.', BOURGEON G .', GUNNELL

CLAUDINO SALES V.'& CANER L.' I.Lab.eatoire du g ographic physique.CNRSUMR 8591 . Ulm ersitcPalis-Srxiwmne, Paris, I' -75005 France.

L-mail : Frungils hturd,ipuri,-14rrfinnrw ..tr

: .CIRAI),t!PR Rtsiycluge et Risque, Montpellier, F-34398 I ions. 3 .l .atxrra rem ilk igcrnphle physique,CNRSt'MR 8541- tlniversite Pans 7, Paris. I -75005 Franca.

4 .1 Miuersidade Federal de Ceara, Campus do Nei, Faxtrk2a, CF-60451-170 ttrlvil. 5.ifiakASA,CNRSIJMR 6532, Linirersitc dc Poitiers. Poitiers. F-86000 France.

2. Methods and survey procedure

Fig1-U :Wan eaP orne shirty area Onshore topography Ram

ameSRTM_GTOP030

Fig.2 -5)ta0rsib sectionmanas

at Situ.massif showing

entesuccession d randfoona. cimabs, vegatdinn. we etterklg peaerns andsois.

.

Our method of landscape system mapping is based on a pedogeontorpftologicat analysis of the landscape This metho d emphasizes the relationships between lendtorms and soils and is easy to use with a genetic soil classification such as the World Reference Base o r the &ethan one (Bourgeon. 1989). Combined with an extensive field work, the survey was performed usingGIStechniques by overlaying a digital elevation model (SRTM 90), topographic maps at 1 :100 000. digital geological data, processed Candeal imagery, and available soil maps . The GtS survey also allowed to take into consideration other fundamenta l environmental parameters such as rainfall distribution and water balance calculations (WBt, length of the dry season) that are useful to

understanding sot distribution and rtreaoscale topographic patterns .

3. Results

_{LANDSCAPE SYSTEM MAP OF THE HUMID BATURITE MASSIF AND ITS SEMI-ARID PIEDMON T}

(NORTHEASTERN BRAZIL) AT 1 1250 00 0

sand covers overlying are Neogene desk s.a.e.

or the B..eew Footman, ‘sub-an 41

4. Conclusions

Philor - Summa Npograplmcsolwe, typical matrcomex brmdseepe or 'memo meter es' aasocide d

mWn Rol vaaey Roma a bas4oils'(subunit,

'Paode-aglraf

Rob 2 - riglry dae tadlandscape net steep slopes

and V-shapedvMbyadominated byresidual rMgmalaic rockdamas(suAura 2)

Flreb3-Chrecbds/c .deceped.soon-and Men

(Sadao) a+Mdinecred mrMbd peAmnaa ermdreRldrral bedrock bndbms (arbvar 31

Photo 4 - Careened Whbterds wan Plena, re aeoaae

1n 10 Jo

5 . References

0

The resulting landscape system map leads us to original conclusions by capturing the key features of the regiona l pedogeomorpftic landscapes: (1) the humid Battail2 massif is characterised by a summit surface (800-900 m a .s .l.) exhibiting meia laranja topography with monosiaXitic weathering and low-activity-day Acrisole; (2) a sub-humid peripheral oree of highly dissected landscape (200800 m) displays more shallow weathering and sod profiles (Uxtaole) ; (3) in the surrounding plain (0 -200 m) . the semi-arid 'Sertão' is a landscape of dissected pediments with shallow bisialitic grits associated with red Luvisot s and brown Cambisols; (4) dissected tablelands form the low-lying 'Tabuleiroi where Neogene elastic sediments are cappe d by

*Altaic

BOURGEON G . 1088 - Esp anebry booklet on Me reconnaissance sail harp ofrarest area. NbMenr Kanne e and(loa. Trav .Sect Su Inst.Fr Peddwry, h. air.. 20. 203 w

creu 2003 - atlas agrtat as pmbgo e recries miaras do Ceara. Mapasnaestate 1100000. Service Geologco do Brasil. CD Ran

FAO. 2006 - sobrá Reksies e Base for Sc. Reno ant A Motorrak brilpr maipnel miaarcalos. cane..

andmaarrataaon. suo. Soil Resources Report 103 128 pp

RADAMBRASIL 1081 - LavaVamesu apegado max wowsus oat.. doBass.Fona Jeguabe-Natal. thretério da lana e Energia-MIE. Riode Janie .Tt0 re

siBCS. 20. - Shawrma Bas.O de eaeaaabarao de Solos . 2' Mk*. EMBr1APA . Rode Janeiro. 360pp.

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