Laterite preservation and soil distribut (1)

Laterite preservation and soil distribution in the Araripe-Campos Sales area,
Northeastern Brazil: consequences of uplift, erosion and climatic change
3 500

A

a

n

3 000

ti

40

c

00

Parnaiba

tl

Camocim

O

MERUOCA

Paracuru

1020

c

IBIAPA
BA

PI

R

Fortaleza

1115

BATURITÉ

SERRA
DAS
MATAS

Poti
io

20

Aracati

00

1124

Quixadá
gu

ar
i

Crateus

a
oJ

CHAPADA DO APODI

Apodi

Ri

CE

744

MARTINS

Iguatu

Macau

Mossoro
be

o Pir
anhas

Fig. 1 - Location map
of the study area.
Onhsore topography from
the SRTM GTOPO30

Rio Ac
a

i ba
rn a

Pa

1099

n

The existence of laterites in semi-arid Brazilian “Nordeste” is a phenomenon poorly described in the literature, probably because of their
weak occurrence in the landscapes by comparison with other tropical shield regions (e.g. West Africa, Western peninsular India). However,
remnants of lateritic crusts have been recognized in a few areas, on small mesas capped by the Serra do Martins sandstones (Pereiro, Martins:
Fig. 1) or on the Campanian limestones and younger sediments of the Chapada do Apodi (Peulvast & Claudino Sales, 2004). One of the most
extensive areas of lateritization in NE Brazil is found in the Araripe-Campos Sales area (southwest Ceará). The objectives of the current work
are: (1) to precise the distribution and characteristics of laterites and soils in the selected area, and (2) to explore the laterite evolution and soil
development in terms of morphotectonic models because of the fundamental controls exerted by tectonics, erosion and changing climate on

pedogeomorphic landscapes at the Cenozoic time-scale.

IRAUÇUBA

a

Sobral

ra

u

e

1. Introduction

40°W

F. BETARD (1) *, J-P. PEULVAST (2), V. CLAUDINO SALES (3)
(1)

DEPAM, Université de Paris-Sorbonne, Paris, France
(2)
IDES, CNRS, Université de Paris-Sud, Orsay, and DEPAM, Université de Paris-Sorbonne, Paris, France
(3)
Universidade Federal do Ceará, Campus do Pici, Fortaleza, Brazil
*
corresponding author e-mail : francois.betard@paris4.sorbonne.fr

Santana
Santana

Ri

PEREI
PEREIRO
REIRO
RO

Natal

RN

Study฀area
Souza
State border

Patos

Campos
Campos
Campos
Sales
Sales

Main cities
Main rivers

1002

ARARIPE

PA

1197

Crato

João
Pessoa
Jo‹‹o Pessoa
Jo

Campina Grande

BORBOREMA

Exu

1185

Altitudes (m)

Recife

0 - 200 m
200 - 400 m
400 - 600 m

Sã
oF

SOUTH
AMERICA

600 - 800 m
800 - 1 000 m

PE
ran
cis

co

1 000 - 1 200 m

BA

2. Physical setting of the study area

Araripe

Precambrian
basement

Granitoïds

Albian฀lacustrine
and฀marine฀deposits
(Santana฀Formation)

Cenomanian
sandstones
(Exu฀Formation)

Fig. 2 - Simplified geological map
of the study area
(source: CPRM, 2003)

Araripe

฀฀฀Topography
฀฀90฀m฀SRTM฀DEM
altitudes฀in฀metres

300 - 400 m
400 - 500 m
500 - 600 m
600 - 700 m
700 - 800 m
800 - 900 m

Cenomanian
structural฀surface

Geomorphology
1

Exhumed฀Pre-Cenomanian
planation฀surface
1-฀Degraded

Low฀planation฀surface
(”Sertaneja”฀surface)

Fig. 3 - Geomorphological map
of the study area

3. Laterite and soil distribution

Fig. 5 - Soils and weathering patterns
in the study area

Data acquisition and terminology

0

10

0

Campos฀Sales
0

65

Araripe

750