The Upper Paran/~, River (Brazil): Geomorphology, Sedimentology and Paleoclimatology

THE UPPER PARAN/~, RIVER (BRAZIL): GEOMORPHOLOGY, SEDIMENTOLOGY AND PALEOCLIMATOLOGY

Jos6 C. Stevaux Universidade Estadual de Maringd, Department of Geography, N~cleo de Pesquisa era Limnoiogia lctiologia e Aqiiicultura (NUPELIA), Grupo de Estudos Multidisciplinares do Ambiente ( GEMA ), 87020-900 Maringd, PR, Brazil

This study involves the geomorphological,sedimentological and paleoclimatologicaiaspects of the Upper Paran~ River at Porto Rico (State of Paran(t, Brazil). The alluvial plain is composedof a braided system (main channel) with island and sandy bars, and an anastomosingsystem (involving secondary channels, tributaries and a complex of swamps, pools and natural levees). River discharge in its upper course varies from 8400 to 13,000 m3/s (minimum of 2550 m3/s and maximum of 33,740 m3/s). Solid discharge reaches 27 x 106 tons/year for suspended sediments and 3 x 106 tons/year for load sediments. Througheehobathymetric survey,bed forms were grouped in ripples, megaripples, dunes and sand waves. A detailed study of the sedimentology,heavy minerals and facies architecture was applied to the two major geomorphicprovinces and their subenvironments: channel province (with sand bar and bed form deposits) and overbank province (with natural levee, flood basin, crevasse and island deposits). Palynological preliminary studies show that during the Late Pleistocene the area was dominated by grassland and savannas under drier climatic conditions. Since the beginning of the Holocene there has been a generalized transition to a humid phase and the present Broadleaf Forest occupies the area. Some hypotheses can be formulated for the evolution of the area. (1) The first order architectural element channel (CH) was generated during the Pleistocene associated with climatic changes and tectonism. The alluvial valley was filled up by alluvial colluvial deposits at the end of the Pleistocene (channel deposits present > 40 ka BP). (2) Tectonismand climatic changes (Atlantic Climatic Optimum) generated a new valley bottom (5-8 m below the former level) and a wide meandering plain was built up (4000-4500 BP). (3) A recent fluvial system created a new terrace 3 m above the normal water level.

INTRODUCTION upper course of the river. From 1972 to 1978, the Upper Paran~i River presented, just upstream of Sete Quedas Falls, The ParaWi River is the tenth largest river in the world as a total solid discharge between 9.89 x 106 and 30 x 106 measured by discharge; the second largest catchment in tons/year, 9.59 x 106-27 × 106 tons/year for suspended South America and the principal river of the Rio de La Plata sediments and 0.3 x 10-6-3 x 10-6 tons/year for bed load Basin. From its source, at the confluence of the Paranalba sediments (Itaipu Binacional, 1990). and Grande Rivers, Brazil (lat. 20°S), to its mouth in the The Brazilian part of the Paran~i River Basin has had its Plata Estuary near Buenos Aires, Argentina Oat. 34°S), the hydrological and limnological regime considerably altered Paran~i River is about 3780 km long. The Paran~i River Basin in the last decades. At the beginning of the sixties the total has an area of 2,800,000 krn 2 and drains all south-central dammed area was approximately 1000 km 2, whereas at South America, from the borders of the Andes to the Serra present this area is close to 20,000 km 2 (Fig. 2). do Mar just along the Atlantic Coast (Fig. 1). The Paran~ River's hydrological basin consists chiefly of Porto Rico Area sedimentary and volcanic rocks of the Paran~i and Chaco The studied area is situated near the town of Porto Rico Sedimentary Basins, whose borders are constituted by (lat. 22°43'S, long. 53°10'W) between the mouths of the highlands of the eastern flank of the Andes and Precambrian Paranapanema River and Ivai River (Figs 1 and 3). At this rocks of the Brazilian Shield on the north and east (Petri and point the hydrological basin area is about 670,000 km 2. Here, Fulfaro, 1983). the Paran~i River has a large, braided channel, 3.4 ~.0 km in The Paran~i River alluvial trench is divided into three width, with an extensive alluvial plain in its right margin. major parts: an upper course, from its source to the Itaipu This plain is drained by a complex involving the Paran~i Dam near Foz do Iguaqu; a middle course along the secondary channels, Ivinheima and Baia Rivers. Paraguay-Argentina Border; and a lower course from the There are many lakes, back swamps and secondary Paraguay River confluence near Corrientes (Argentina) to streams, forming a typical meandering-anastomosing the Rio de La Plata Estuary. alluvial plain. The wide area may present fairly recent The Upper Parantt River, with an extension of 809 km and subsidence m possibly some type of small neocratonic basin a basin of 820,000 km 2, has only 500 km not impounded, and where the Ivinheima River, which comes from the State half of that will be modified by the Porto Primavera of Mato Grosso do Sul, is situated. Reservoir, to be finished in 1995 (Agostinho et al., 1991). The annual range of temperature varies from 10.3 (winter) The Ilha Grande Hydroelectric Project, whose construction to 33.6°C (summer), with an average of 22°C, and an annual was suspended, would eliminate the last lotic reach of the rainfall of 1200 mm (University of Maringa Meteorological

143 144 .i.c. Stevau:.,

STATE OF MNITO s~o ~o MMIAVlII A (IRAZIL)

s~Jos~

JIHCO

.z,L 4° STATE OF

PARANA (BRAZ IL )

~- IttZILIAN SlilS*LD

. Allies CJqlLI,ilIA ITAIPU RESERVOIR IUAIIIA |SETE O

~ - I[AITI[IIN PLA,k~I

! 0 ZO xm J FIG. 1. Studied area in the geological and hydrological contexts (after Iriondo, 1988 and Agostinho et al., 1991).

Station), so that the region has a tropical-subtropical climate. high gradient (4.2 m/km). They develop rapids in relatively In the Fluvial Station of Port S. Jose (Fig. 4), in the deep and narrow canyons eroded on the Caiua Formation. Paranapanema River mouth, the Paranfi River has a discharge that varies from 8400 m3/s in the dry season of Unit Taquarugu June, July and August to 13,000 m3/s in the wet season from This occurs in the NW and Western portions of the area November to March, with the highest discharge registered as 33,740 m3/s (in 1983, with a recurrence of 27 years) and the lowest 2550 m~/s (in 1969). In the study area the gradient of the Paran~ River is about 0.096 m/kin. amularJ.m arm (htx 100o) The area belongs to the Highland of Alto Paranfi ~ o 4 8 12 16 20 Geomorphological Region (Justus, 1985), which is ! dominated by very smooth hills gently tilting to the Paran~i I=---L 18. 1910-19 i River. Four major geomorphological units can be found 1~0-25 1930-39 along the alluvial trench (Fig. 5). 1950-59 Unit Porto Rico This unit consists of the Mesozoic eolic sandstone of the Caiua Formation covered by a 1-8 m autochthonous sandy soil layer associated with colluvial deposits named the o 20 /~ 60 18 108 118 Paranavai Formation (Popp and Bigarella, 1975), and forms of m almost all the high and steep eastern bank of the river. The landscape is constituted of low hills ranging between 250 and 320 m in altitude, with a hydrographical net of rivers not FIG. 2. Upper Paran~ River hydrological basin. Impoundedarea evolution longer than 20 km (except the Paranapanema River), and (after Agostinho etal., 1991, Fig 2). The Upper Paran~ River (Brazil) 145

FIG. 3. The Porto Rico area. MS, State of Mato Grosso do Sul; PR, State of Paran~i; SP, State of SAo Paulo, Brazil. Landsat image (black bar on the top is 10 km). and 15--45 m above the Paran~i normal water level. It consists Unit Rio Parand of a high colluvium terrace where hundreds of small lakes This unit is the proper Paranh River alluvial plain and can be found. These lakes probably originated by pseudo- consists of high and low flood plains, island, bars and a karstic processes during ancient dry periods very similar to secondary anastomosing system. Almost all lakes and back the forms described by Popolizio (1975, 1992) in the swamps in this unit are flooded every year during the wet Paran~--Corrientes River area in Argentina. season. Two levels of limonite-cement gravel, identified by Fulfaro (1974) and Boggiani et al. (1985) as 'Quartzite and Unit Fazenda Boa Vista Agate Generations', are possibly the oldest deposits in area This unit is a typical alluvial-colluvial terrace rising 8-10 related with the geomorphological and sedimentologieal m above the Parami River water level. It is formed exclusively history of the Upper Paranfi River. They occur in the highest by sand and irregular lenses of gravel with many levels altitude of the northwestern portion of the study area (Fig. 5) bearing limonite cement. A great number of paleo channels and paleocurrent analysis show that these deposits have and levees suggests that this unit was strongly reworked by come from the north and northwest. Fulfaro and Suguio the ancient Ivinheima River meandering system. (1974) attributed a Neogenic age to these deposits.

.J m

o E 0 2,5

35.000- 30.000" W ZS.000. 1°|.: se ZO.O00, MAXIMUM _ 15.000 • gI 1. 1,1 s- 10.000' AVERAGE 5.000.

~ Ig70 lgO0 1990

FIG. 4. BoUom: discharge of the Paran~ River at Port $6o Josu Fluvial Station from 1960 to 1990. The catastrophic flood of 1983 reached 33,740 mVs. Top: Variation in areal extent of a group of islands from 1953 to 1990. 146 J.C. Stevaux

W~"30' ,, W 53"15' W53"00' W52*45 + ! I I \ . f I J 2 J, tO i J ill • t 2 B , ~o S A • I 22" F,,, 30 ° + "J,21 Iq~IUAVERA DAM

ROSANA OAM 3b

2a"

r'e* ".2q" "" Y+b " s~o~ 1 ~eO~ o / "'" .." ~¢vKnsijv o,~ MARINSA BASE 60* 40" PORTO RICO l A' 2a 0 o 0"

PORTO ~0 AItEA 0 5 lO 15im I I I I so" m" 1

40, 4o" QUARTZITE AND 4eAT[ GENImATIOA~S Ira! / +oo~ £x..nmllU, ,o ,o- +o.

GEOMORFOLOGICAL UNITS

l - PORTO RICO (GAIUA FORMATION) 3b - FAZENDA BOA VISTA * LOW m . (MWI.OICAL LINEAMENT

2 - TAQUARUI:U 3¢ - FAZI[NDA BOA VmTA - FAN - LAKES ("DALES") Z* - TAQUARU~U/IVINHEMA 4 - RIO PAIIANA

~kl - FAZ~IImA BOA VISTA - HI611 5 - RIO PARANAPANEIIA . RIYIK/W, IO0~S ~ ISLMiOS

FIG. 5. Geomorphological units of the Porto Rico area. The Upper Parar~ River (Brazil) 147

POIl'fO Ille~

.a,

FIG. 6. Block diagram showing the Parar~ River channel asymmetry (after Femadez, 1990, Fig. 22).

Fluvial Geomorphology fluvial dynamic. There is almost no flood plain along the left The channel pattern in the Parana River from the margin, so that the fiver continuously erodes the Mesozoic Paranapanema mouth to the Sere Quedas Falls canyon sandstone of the Caiua Formation. However, in its right (covered by the Itaipu Hydroelectric Dam) is typically margin the Paran~ River built up a large flood plain. The braided, with a large number of islands and sandy bars (Fig. multichannel morphology occurring in the main channel can 3). However, an accurate analysis shows that this segment be divided according to its fluvial characteristics (Fig. 6). has a mixed pattern. The main channel is braided but the Along its south side, erosional-depositional dynamics have secondary channels, in the flood plain on the fight margin, been intense such that the talweg has totally shifted to the left are anastomosed according to the concept of Smith (1976). The strong asymmetry of the alluvial trench geometry t. ~rt ~ .k~ (mh po~t) (See Fig. 19B, C) shows a possible tectonic control on the

3O i~ • XO00

600 ~%%%%%

• s AI

1~0 1970 1~0. 1990

IC 5 FIG. 8. Talweg migration in three cross-sections in a braiding oftbe Upper Q1 (m s. 8-]-) Parm~ S~-tion port Sgo Jos~ is a node point where the talweg presents high stability (migration velocity 2.7 m/year); section University of Maringa FIG. 7. Upper Para~ at Port Sic) Jo~. Relationship between concentration Lab. is in the upslremn part of a braid (migration velocity 13.4 m/year) and of suspended material (mg/l) and liquid discharge (QI). Note the anti- section Porto Rico is in the middle of a braid (migration velocity 56.6 clockwise cycle for the 1988-1989 flood. m/year). Localization on Fig. 9. 148 J.C. Stevaux

n0A~l LJ~nOIWO, W'

-/ v A i,...s-o IL

A A"

I Q/,J'~ m _A

II B'

.,iL O' 1.t Olilll 1 C l

]0,0-

C i., HG. 9. Eehosnun of longitudinal sections (localization at the top). A-A': main channel (in a braid); the first order bed forms are dunes, the second order are r~gmil~s and the third order are ripples. B-B': secondary channel (in a braid); the first order bed forms are mes,luipplcs and the second order are ripples. C--C': unichm~nel (in a node point), the first order bed form is large and flat with isol~ed megmpples and tipples. margin. Here the channel is about 13 m deep with a flow and the flow velocity is less than 0.9 m/s. Thus, the channel velocity of 1.4 m/s. On the opposite side, the fluvial and alluvial deposits' asymmetry suggests fairly tilted dynamics are reduced, the depth does not exceed 5 m and the subsidence of the right block against the high one of the left flow velocity is less than 0.9 m/s. Thus, the asymetry of the margin. alluvial deposits suggests tilting of the right block towazds The anastomosed channels of the external border of the the high left margin. Here the channel depth is about 13 rn flood plain comprise a complex with the Baia, Curu;aba and with a flow velocity of 1.4 m/s. On the opposite side the Ivineima Rivers and secondary channels of the Paran~i River. fluvial dynamic is reduced, the depth does not exceed 5 m These channels present low to high simuosity (1.2 to 2.1). The Upper Parar~ River(Brazil) 149

LEFT IN ISLAND

• IOO IOO 300 400 SOO IOO "/'OO •OO p'tm) --4 O"

• oZ L: I q: I: I: 2 -+4 • 3

SOflTme

-4 PEMLE -4- STANDARD DEVIATION 0 - I WELL

-2 COARSE SAND •.-, AVEIIME I - Z WELL TO IIO0~RATED

O IIEDiUM SAND :) - 3 POORLY TO IIO~RATI[I)

+2 FINE SAND 3 - 4 POOIqL¥

+4 V. FINE SANO FIG. 10. Comparationof grain size and sortingdistribution in a main channelof the Upper Paran~ River. Grain size average (-) variesfrom +1.0 to +1.5 phy; standarddeviation (+) varies from0 to 1.

Actually, since 1953, studies from aerial photographs ephemerous channels with associated splay may occur, or confirm the low activity of these channels, restricted to abandoned channels may even become reactivated. which is lateral accretion, natural levee build up and mainly The anastomosed secondary channels are influenced not avulsion processes that may separate channels many only by the water of the Paran,~i River but by the Ivinbeima- kilometers long. As this complex is controlled by the Parana Baia floods as well. The interrelation between the floods of and Ivinheima regimes, the water in the secondary channels the Paran~f and Ivinheima-Baia systems controls the may flow downstream or 'upstream' according to the relative magnitude of 'catastrophic floods'. In this case, the water discharge of each. totally invades the alluvial plain, forming a large channel 8 There are many lakes and swamps associated to the km wide. anastomosed branch of the Parana River, and they are very important environment for local ecosystems (Agostinho et Bed Form al., 1991). Bed forms and bars morphology change drastically and talweg tends to drift continuously in the Paran~i braided Water Regime and Suspended Sediments channel. Drago (1990) characterized these movements in In spite of two great dams just upstream of the area two distinctive types: (1) gradual and continuous transverse (Rosana in the Paranapanema and Porto Primavera in the movements and (2) sudden shifts from one position to Paran,t), the Paran~i River section at Port S. Jos6 is very another. The magnitude of the movement of the talweg from important to the local hydrology, because it constitutes a a stable marker is studied in three different cross-sections node point controlling the braided reach downstream. The (Fig. 8). Cross-section Port S. Jos~ shows a talweg shifting main influence of the dam on the river system dynamic is about 2.7 m/year. This section is a node point that operates probably the great decrease of load sediment, especially of as a zone of bypass of energy in the system. On the other coarse material. Suspended solid concentration in the Paran~ hand, section Porto Rico shows a significant displacement River at this section varies from 30 to 6 mg/l. Suspended of the talweg, reaching 56.6 m/year. The intermediate sediment concentration and water discharges during section University of Maringa Lab. shows an average shift of 1988--1989 (Fig. 7). From April to November (dry season) 13.4 m/year. there was an increase in solid concentration, and a decrease Using the same terminology proposed by Drago (1990), from December to January, during the flood period. four bed forms can be found in this reach of the Paran6 River: During the normal floods the channel water invades the plain by overflowing the natural levee and abandoned (1) Ripples: are forms with wave height from few to 30 channels. The flood is gradual and calm, with no effective cm. Generally, the ripples are superimposed on the upstream unidirectional flow, except locally where levee crevasses face of large bed forms. may occur. At these points the flow is more intensive, and (2) Megaripples: range from 30 cm to 1.5 m and are 150 J.C. Stevaux

(A)

BANK BANK -)TYP( - A TYIq[ - II TYPE - C

[ I I

II)

A TV~ • TW'G c

BANK NENINT Hill LOW LOW

FLOW VILOCITY NIGH NIOtl LOW

TRANIVIHIIIAL STEEP STEEP IIfJITLE PROIrlLE

litOM~ OF MATEIIIAL RAPtO RAPIO SlOW

elU~Ut.MIETRY gOdtRIll FIM

II FIG. 11. A, B and C mar~n types of the Upper Paran~ River and their fi~olo~c, topograp~c and erosional characteristics (after Fernandez, 1990). linguoid and lunete in shape. Megaripples are forms with probably related to the catastrophic floods and responsible high mobility, like ripples. for the bar construction. (3) Dunes: have wave heights ranging from 1.5 to 7.5 m An echogram survey was made in three different and lengths from 50 to 500 m. They are perhaps the most longitudinal profiles in Paran~ River channels (Fig. 9). In the common forms in the upper course of the Paranfi River. echogram from the mare channel, with de~ above the cfist (4) Sand waves: are the largest forms with heights ran~ng from 5.5 to 7.5 m and flow velocity near the water reaching 13 m and lengths of 1000 m. Sand waves are surface of about 1.3 ntis (Fig. 9A), the fLrst order forms are

A lo.o0o I ~,

i"] , . .d c

J~ ~ ~VO~ IWE m~m ~ ~m Jim

1~ 1~9

FIG. 12. Correlation of hydrological conditions, rainfall and erosion rates for three types of margin from July 1988 to August 1989 (after Fernandez, 1990). The Upper Paranl River (Brazil) 151

profile is a planar wave gently dipping upstream (1.3 m/1000 G • 6 m), where only isolated ripples and megaripples appear. C Grain size of the bed load in a transversal section at Porto Rico ('Fig. 10) is very homogeneous and well sorted, with the mean between 1 and 2 phi (medium to fine sand) and \ I" standard deviation lower than 1.0.

Bank Line Alteration Banks are continuously altered by shifting of erosion and deposition zones. Fernandez (1990) classified the Paranfi River margins in three types:

(1) Stable bank: occurs along almost all of the left margin of the river, constituted by the highly resistant sandstone of the Caiua Formation. (2) Accretion bank: this margin is a type of 'lateral bar' that normally develops downstream of islands or pre-existant margin. It has high depositional rates and is generally covered by vegetation. i~1 mtlsm ~ manta MIBU (3) Erosion bank: this is the margin that presents continuous recession. It forms steep faced banks with heights ranging from a few centimeters to 3 m above the water level. Fernandez (1990) measured the rates and processes of HG. 13. Types of bars in the Upper Paran& (A) central bar and (B) lateral eroding banks between 1988 and 1989 using a pins and pegs bar (modifiedfrom Santos et al., 1989, Hg. 3). method. Thirty active eroding banks were monitored and grouped in three prominent types: A, B and C (Fig. 11). The morphological and sedimentological bank conditions and the dunes 2 to 3 m in height and 200-400 m long. They are not flow characteristic were the basic parameters used in this simple forms but incorporate secondary ones as megaripples classification. The mean annual erosion rates for A, B and C and ripples. The second echogram (Fig. 9B) made in a types were 4.08, 1.40 and 0.51 m/year, respectively. The secondary channel of braided system with depth less than 3 correlation between data of hydrological conditions, rainfall m (above the crests) and flow velocity 0.9 m/s. The bed amounts and erosion rates for three types of bank are shown forms are essentially megaripples 0.5-1.9 m in height and in Fig. 12. There are two main erosion processes, corrosion length ranging from 30 to 150 m. The third echogram (Fig. and slumping, that increase activity during the flood period. 9(=) was profiled in the unichannel reach of the river near Rotational sliding occurs secondarily in some high, very Port S. Jos6 (node point). The most spectacular form in this cohesive clay-rich banks.

~BR all6R

~K: C N8 F vF • C C N F vF

90 90.

gO '80, 70 70 60 60 50 50,

40 40

30 30 mk 20 ~1s97 10

FIG. 14. Cumulative frequency curve for samples from lateral bars and central bar. 152 J C. Stevau×

TABLE 1. Lithofaciesclassification, from Miall (1978. rood. Facies code Lithofacies Sedimentary. structures Interpretation Gins massive matrix supportedgravels grading debris flow deposits Gm massive or crudely bedded gravel horizontal bedding, imbrication longitudinal bars, lag and sieve deposits Gt gravel trough crossbeds ~rtinor channel fills Br* resedimented blocks massive Sp sand medium to coarse and pebbly planar crossbeds dune and megaripples Sr sand, very fine to medium mud ripple drift and climbing, drape and lenses low velocityflow Sm sand fine to coarse massive fluidization So't sand fine to very fine, organic-rich mud lamination,bioturbation and mottled Sh sand fine to medium planar stratification main channel bed form S1 sand fine to mud planar lamination low velocity flow Fm silt and clay massive, rootlets overbank deposits FI mud and fine to very fine sand planar and rhythmic lamination levee deposit

*Stevaux (1993). tSantos (1991).

The fluvial channel dynamic is controlled by the river middle of main channels with a length of 200-1000 m and regime, so that intensity, duration and recurrence of flood are length/width ratio of 3 : 1. The sand varies from very fine to responsible for the modeling of the erosional or depositional very coarse (Fig. 14), with prominent granulometric forms. The area variation of a group of islands was alternation among the sets. Subordinately thin levels of mud monitored for 37 years (Fig. 4). In 1953 the area was about may occur without expressive lateral continuity. The 2.7 km 2 and this value increased until 1966, reaching 3.6 deposits are composed essentially of quartz (>95%) and km 2. At this period the increase in area coincided with the mica (5%); the main heavy minerals are opaque (magnetite), increase in the highest and medium annual discharges. Since amphibole, pyroxene, staurolite, kyanite and sillimanite then, the group of islands has been dominated by the (Table 3). erosional process and presented a reduction of 0.42 km 2 in Two faciological associations related to the genetical area in 1970 (corresponding to 11% of the area in 1966). This phase of the central bars are found in a typical vertical profile reduction coincided with a strong decrease on the maximum (Fig. 15A). The initial phase, denominated protobar (Santos, and mean annual discharges. From 1970 a new cycle was 1991), is constituted essentially of Sp facies at the bottom initiated with an increase of 0.2 krn 2 in the area of the group and St facies at the top. These facies were deposited as dunes of islnnds (about 15,000 m2tyear). For the same period the and megaripples during the sub-aquatic phase of bar discharge also increased, reaching a peak of 34,000 m3/s in construction. In the second phase, the bar was reworked by the historical flood of 1983. shallow water processes relating to flood reflux and by wind action. The faciological association of this phase is SEDIMENTOLOGY, FACIOLOGY AND composed by facies Sr and So originated by ripple bed forms, MORPHOGENESIS facies S1 (eolic) and facies Fm (suspension). During the floods, small 'natural levees' are deposited at Fluvial sediments were described using the lithofacies the bar's upstream face (Fig. 13), forming protected shallow classification of Miall (1977, 1985), with two additional pools in the inner part of the bar. In these places, primary specific facies observed in these deposits. Lithofacies, with herbaceous vegetation may develop, contributing to bar their respective sedimentary structures and interpretation, stabilization. These deposits can migrate hundreds of meters are shown in Table 1. Six major deposits were identified for or even totally disappear in the intensive floods (Santos, the alluvial and associated sediments, and could be grouped 1991). into three geomorphic provinces (Table 2). Lateral bars develop beside the margins and island due to shadow zones originated by topographical particularities Channel Province (Fig. 16). In these zones the flow velocity falls below 0.9

Sand bar deposits TABLE 3. Heavy mineral composition (%) Paramt River sand bars were characterized by Santos et al. (1989) and Santos (1991) as central and lateral bars Lateral bar Central bar according to faciology and channel position (Fig. 13). Opaque 60.1 65.1 Central bars are elongated sandy bodies deposited in the Kyanite 7.7 6.5 Staurolite 5.4 4.3 Tourmaline 5.2 3.1 Garnet 4.1 3.8 TABLE 2. Geomorphicprovince and major deposits Epidote 3.7 4.6 Amphibole 7.1 7.5 G-eomorphologicalprovinces Deposits Sillimanite 3.0 2.3 Zircon 0.7 0.7 Channel sand bar, bed form Andalusite 0,7 0.2 Overharak natural levee, flood basin (swampsand Pyroxene 0.8 O.2 ox-bow lakes), crevasse and island Ruffle 0.3 ~).5 The Upper Paran6 River (Brazil) 153

A B

I~ - lil.INiil @lOSS Ill '10 I " FEITOON C. IEO RI :I Ir m . mvv pl . ~,I~ h.l,m

II I

~m ,I( 1-a~o

b Idll m. le t,~I 14

rl lwll II BOOY GEOMETRY "--' Itl~T

A - wBE FI I L v. if,if IiiIy i 0 - TAIULAR i Ii, U. PI I I ~ ,,.m ). J L • FIG. 15. Faciological vertical profiles in channel bars: (A) central bar and (B) lateral bar in the Porto Rico area, Uper Parana River (after Santos, 1991, Fig. 14). m/s, creating a location with high depositional rate. These These deposits present an alternation of muddy facies Fm bars are formed by quartzose fine sand with high sorting and F1 with sandy facies Sp, Sr and So (Fig. 15B). (Fig. 14), with important layers of mud intercalated.Heavy Occurrence of drape and flaser structures indicates fall-out minerals arc less than 2%, prevalently opaques, amphibole and a tractive process. Frequent leaf banks are associated and kyanite (Table 3). The occurrence of unstable minerals with the shallow pools in the inner portion of the bar. (amphibole and pyroxene) associated with metastablc The evolution of a lateral bar in the Porto Rico area was material (kyanitc, sillimanite,staurolite) suggests a source observed over the last 36 years (Fig. 17). In 1953, the process area composed of metamorphic aluminum-rich rocks, began with a shadow zone formation created in the right probably originated from the Brazilian Shield, with recent margin of the main channel. By 1970, with the intensive deposition in the fluvial system (Santos and Fernandez, sedimentation, the protobar attached to the margin and the 1992). bar surface was covered by herbaceous vegetation. In 1980,

I / ...~Li.l~_JIIIIl~o. "e ..of------~.,,,~-"-~.~. ~ ~-"r--'d

f~ ~0 I f~

| fin I

7:/771 m

FIG. 16. Topographic control in the lateral bar formation in the Upper Parana River. 154 J.C. Stevaux

as the hydrological and morphological characteristics remained the same, a new protobar began to be deposited and the latter herbaceous vegetation was replaced by arboreous. By 1989, the last protobar became a lateral bar covered by herbaceous vegetation and a new bar began to be deposited (t989) When a new lateral bar is formed, a narrow channel ('ressaco') develops between the bar and the a0cient margin. With the continuity of the process, each new channel being formed beside the last one generates a very typical pattern in aerial photography (Fig. 18).

Bed form deposits lm j This reach of the river presents a sandy mobile bottom, except in some places with limonite cemented gravel, sandstone or basalt. Ripples, megaxipples and dunes are very common in this area; on the other hand, sand waves are restricted to catastrophic floods. A very significant outcrop could be studied in Porto Primavera Dam, just upstream of Port S. Jos6 where, in a continuous trench of 13 kin, all alluvial deposits are totally exposed. Thus, it is possible to apply the Architectural Elements concepts of Miall (1985). Figure 19 reunites the Architectural Elements identified in that exposition. Figure 19B presents the CH element (channel) in regional scale, where it is about 11 km wide--this is one of the largest o, r~ ml expositions of this element in the world. In Fig. 19C it is possible to distinguish the spatial distribution of the present Paran~i River, where the element SG and, secondarily, GB (respectively 'sediment gravity flow' and 'gravelly bars and

i Ill 195~1 bedforms') occur in the basal portion of the sequence. Architectural elements FM, LS ('forset macro form' and 'laminated sand') and GB are present in the middle of the FIG. 17. Lateral bar evolution from 1953 to 1989 in the Upper Paran~i River, sequence and LA ('lateral accretion') in a thin layer on the Porto Rico are,~ 1953, a sandy lateral bar is deposited; 1970, this lateral bar top. is covered by herbaceous vegetation; 1980, the first lateral bar is covered by arboreal vegetation and a new sandy lateral bar is deposited; 1989, the The three vertical profiles in Fig. 19A present different second lateral bar is covered by herbaceous vegetation. characteristics of this sedimentary environment. In profile 1,

FIG. 18. Typical active-inactive channel pattern made by lateral bar processes in the Porto Rico area, Upper Paranfi River. Aerial photograph taken in July, 1970 (black bar on the left is 1000 m). The Upper Par~ River(Brazil) 155

A ~W p~msf i~ FACES ~ (ml FACIES [trAcers) B.I~BIT .or-~;~i o,o it o,o

,° LA • 2,,....,),, ,, I0 O~Fa OF St/SS

l;s SG N: sG • &O~ i &O l SG FM 2 68 Lm ~ 4A 4,0

PflOF1LE X sp/ss ) SG ~,o~ st/et ism LS O~ Sit k e~

PNOFLE 2 PROFILE 3 I- TAmJ~.~ UmT FAZ.LA VISTAuNrr ~ PMUNAUNIT O(,OIrR

t IO n~ !~" FI: IOn

C .~ FLOOD~LAI# flaIL( Z I'nOlr~[ A IrefUL[ 3 I I

..... I ..... t I z w :: noZ

A & A A t A A ~ A A A A A A A A A A A A A A A A ^ A A a A A A me

FIG. 19. Architecturalelements and faciologyof Para~ Riverchannel &-posits at Porto Primaveradam. (A) Faciolosicalprofiles in the channel deposits; 03) CH element(present and ancient);and (C) spatialdistribution of the architecturalelements of the channeldeposits (after StevatLx,1993). the prevailing Gms facies indicates debris flow as the main is the more representative on Paran~i River deposits, sedimentary process. However, the relative sorting and suggesting that the element FM is in adjustment to the roundness of the clasts suggest that these deposits had present river pattern (Stevaux, 1993). various cycles of transport and sedimentation. Gravel facies (Gm, Gms, Gt and Br) interbedded with Profile 2 presents facies Sp and St with few Gt sandy facies (Sp, St and Sh) are found in profile 3. Br facies interbedded. This profile is very similar to the Plate and shows reactivating phases and instability, with erosion and Donjek Rivers described by Smith (1971, 1972), Williams remobilization of pre-deposited sediments. Blocks of pebbly and Rust (1969) and Rust (1972). The faciology is typical of sand and sandy gravel suggest that sediments suffered some the FM architectural element, whose generator bed forms are extensive diagenesis. In outcrops it is possible to identify sandwaves, dunes and megaripples (Allen, 1983; Kirk, 1983; gravity flow; slump and fluidization. However, the intensive Cant and Walker, 1978; Haszeldine, 1983a, b). This profile actuation of traction flow reorganized the blocks and 156 J.C. Stevaux

GMd FMF corresponds to overbank environments involving a large number of sub-environments that may or may not be m connection with the Paranfi main channel, depending upon flood magnitude. It is interesting to emphasize the importance of overbank deposits, traditionally neglected by fluvial sedimentologists in favor of channel belt studies (Farrel, 1987). The overbank deposits give a more complete sedimentary history than the fragmentary channel records. Information about paleoclimate, paleocology, palinology, macro fossil, paleopedology and absolute dating are preferentially found in these deposits rather than in channel sequences.

Natural levee deposits Natural levees in the Porto Rico area do not exceed 3 m in height and occur in the main channel as well as in secondary ones. The natural levee faciology can be divided into three major faciological units (Fig. 20): (1) a basal unit, constituted by sandy facies Sp and St from the bar phase; (2) a middle unit, muddy borrowed facies deposited in the flood FIG. 20. Faciological vertical profile and outcrop of levee deposits in the plain phase and (3) an upper unit, a thickening and Upper Paran~i River, Porto Rico area. (G) coarse, (Md) medium, (F) fine and coarsening upward sequence corresponding to the levee (MF) very fine sand. Black bar on the left is 1 m. deposits, ubiquitous in almost all right margins of the Paran~ River. Figure 21 shows the evolution and idealized profile of a typical 'erosive margin levee'. Each growth phase (T~, T2, etc.) advances toward the flood plain, resulting in the characteristic coarsening-thickening upward sequence pebbles, building up gravelly sand facies (Gp and Sp), (Stevaux, 1993). common in the GB architectural element. On the top of profile 3 (Fig. 19A) there is a sandy Flood basin deposits faciological association belonging to the LA element. This Six major units were identified in these deposits (Fig. 22). element is often referred to point bar deposits (Miall, 1985), where the sigmoidal foresets transversely shift the channel, Sandy mud with iron nodules unit. Light olive-gray sandy generating a sequence of 'off lap'. However, this reach of the mud with nodular and root traces with iron oxide coating; Paran~i River is straight, suggesting that lateral accretion was SEM and X-ray diffraction analyses show kaolinite and induced by talweg migration. smectite as clay minerals. Fe-oxide precipitant suggests that the environment was well drained, allowing for Fe 2÷ Overbank Province mobilization and subsequent precipitation as Fe 3.. About 70% of the Porto Rico alluvial plain area Centimetrical to decimetrical layers of rooted sand can be

NATUIAL I arVl[ar FLO00 BASIN ""'- liANIN EROSION 1

4'"

- FI.O00 P't.AOm ~ - v ~ SAm

Im-,M leJ. ,,,,i

. um, ,,.r T2 .

FIG. 21. Diagram showing hypothetical evolution of natural levee along an erosional margin (after Stevaux, 19931 The Upper Paran~ River (Brazil) 157

STRATI¢iltAPHIC SEQUENCE , FLOOD BASIN The environment of this unit is the same as the previous one, but in a more proximal splay position. SAND Sand grading to clay unit. This is one of the most common facies on the flood basin deposits in the area. Its granulometry varies from medium/fine cross-bedded sand _ ENVlBOMME~ with clay clasts in the base to medium gray borrowed organic-rich mud. This faciology is interpreted as small .'.¢ • '-..'. [ MASS,rE abandoned channels from Paran~i secondary anastomosing C~.LUVIUM I ". "'." "'" :~ I SA.O channels or local tributaries. • ~ ;'... Clay clasts unit. This unit is constituted of thin levels of ~CLAY IIUD CRACKS clay clasts in a sandy matrix and is interpreted as the product W.JII~IIII~NTLrO 1 ~ CLASY$ of sub-aerial exposure of the swamp bottom (mud cracks formation) and re-sedimentation in the next flood. This unit is very important in paleoregime studies, because it may identify periods of complete dessication of the flood basin. BACK SWAMP (DISTAL SPLAY L,O~) Peat and clay unit. A 0.5-2.0 m layer of peat inter- m, fingered with organic-rich clay, with leaves and logs fragments; lamination is partially obliterated by uJ bioturbation. This unit was deposited in back swamp or shallow pool environments. BACK SWAMP (PROXIMAL SPLAYLOBES) Massive sand unit. This facies is derived from colluvial-alluvial processes on the sandy geomorphological units (Porto Rico and Fazenda Boa Vista) and it can be randomly associated with other units. When sand is deposited in thick layers inter-fingered with peat or organic- ( Il PEAT AND CLAY BACK SWAMP AND rich clay in a well drained part of the alluvial plain, the high SHALLOW POOLS pH of subsurface water can mobilize the Fe-oxide coatings of the grains, and the sand becomes very clean.

Crevasse deposits The Paran~i River's natural levees are not continuous, so SECONDARY that water floods often enter the plain before the levee ABANDONATED overflows. This diminishes the channel water stress on levee TO CLAY CHANNEL walls, avoiding crevassing. The complex of channels originated by the lateral bar accretion process (Fig. 18) L~_x~ distributes the flood water, diminishing the stress. Thus, when the bankful level is reached, all of the plain is already KEY inundated, and in strong floods, the plain, as a whole, operates as a great channel. In this case the bed load passes [~- IFK)N NOOULES !~- ROOT HAIRS over the plain, generating bed forms like those found in the --"~l" CLAY GLASTS ['~- WORMY FABRIC main channel. The predominance of Sp facies indicates that the 'crevasse' deposits in the Paran,'i River display the same PLANAR LAM. "~----]- CROSSLAMiNAYION faciology as the channel.

FIG. 22. Idealized faeiological profile for flood basin deposits in the Upper Island deposits Paran~t River. In spite of the islands' occurrence in the channel, their interpreted as splay lobes (Farrel, 1987). Sand grains sedimentary processes are closely related to overbank dispersed in the mud suggest colic origin, probably under environments. These forms are originated from channel bars semi-arid conditions with limited plant cover in the area. The followed by aggra~tion produced by flood process. Island environment for this unit is interpreted as shallow back morphology develops from depositional and erosional swamps subjected to crevasse activity (small channels and processes whose equilibrium defines its permanence or splay). disappearance from the system. A representative profile obtained from vibro corer and Silty sand unit. Silty and muddy dark gray fine sand, elucidates the island formation (Fig. 23). The fn'st phase bar bioturbed by roots, with incipient planar lamination. Worm deposition, and the second involves vertical accretion and root tubes may be infilled by peUetal clay iUuviation. originated by the flood process. The island sequence is 158 J.C. Stevaux

U MWP'U "S" CU~Vg( MU.AlrJVE DIS'TANU ~ ~ CNA/m

m am# U

¢ IEN01Vt NANIN UEVH

~Fm

I /l I FL001) KAIN I I' I j.

i ~ LEVtE

/Fm FL000 PLAIN $

IqlNIAIIY LtVEE 2 CNAN~L / BAR

.ooT I- "LAW LJm.,O,, .ILT

FIG. 23. Fae~l vmic~ profile,del~tio~l envL,~t and ~ ~ ~ ('13' curve)in a ci~l i~ of the Ul~ t~ River,near PoFto Rico. 'G' curve is the distance between the margin and the profile. (I)~clq~dts- 'G' tempe in O;,(2)stable bar ~- 'G' curve goes far from O; O) aggradation processes -- 'G' curve comimm far from O; (4) ~ inemlml margin condilion-- "G' curve tends to O:. (5)~ condition -- 'G' curve stable far from O; and (6) c=osional margin levee (pmaU s#mlion) ~ 'G' cm~e back to O (after Stevaux, 1993). composed of bar deposits followed by natural levee deposits PAI,EOCLIMATOLOGY (depth 2.1-4,0 m.). About 2.5 m of muddy seAimcnts were dvposited in the flood plain environment. F/trolly, a natural Pa_lynological studies in the area are very scarce and levee sequence ends the island depositional history (depth remitted to only a few samples collected in the main Upper 0.0-2.1 m.). Paramt River hydrographic sub-basins in the State of Parami The Upper Paran~ River (Brazil) 159

TABLE 4. Correlation among palynological samples from Paran~ River sub-basins and the Porto Rico area (after Jabur, 1993 and Klein, 1975)

Epoch I H HI IV

Holocene Araucaria forest, Araucaria forest, Paran~Umguay Basin Pmmut Uruguay Basin broadleaf and savannah broadleaf and savannah Broad leaf forest Broad leaf forest Pleistocene Gramineae Gramineae Gramineae Gramineae (Late) Compositae Compositae Compositae Compositae Umbelliferae Umbelliferae Myrtacea Myrtacea Podocarpus Podocarpus Amaranthacea Mau.ritia sp. Palmae Typha Palmae Typha Typha Pleistocene Oenotheraceae Oenotheraeeae -- -- (Early) Urticaceae Urticaceae Araceae Araceae

I, Tibagi River (S 25°10'50"/W 50°38'00"); If, Piquirivai River (S 24"07'50"/W 52°14'00"); HI, Umuarama (S 23030'00"/W 53°30'00"); IV, Porto Rico (S 22*00' 10"/W 53°06'00").

(Jabur, 1993). Table 4 presents an expeditious correlation In this last humid phase, the Paran~ Basin was occupied between the palinology of these sub-basins and samples from by the present Broadleaf Forest (Klein, 1975). Nevertheless, the Parami River alluvial plain in the Porto Rico area. During a significant fall in the relative sea level curve between 3500 the late Pleistocene (between 25 and 10 ka BP), the area was and 2000 BP seems to be correlated" with an interval of low dominated by grassland and savannas under drier climatic frequency of pollen (drier climatic conditions?) in the profile conditions, as suggested by the low frequency of pollen (Fig. of Fig. 24. 24). Since the beginning of the Holocene there was a generalized transition to a humid phase, reaching a climatic QUATERNARY EVOLUTION 'optimum' at about 5 ka BP identified by Jabur (1993) as the 'Optimum Atlantica'. It is very suggestive that this event Unfortunately, the greater part of the Upper Parami River corresponds to the highest sea level in the SE Coast of Brazil and associated deposits are flooded by hydroelectric dams, according to the relative sea level variation curve presented hence the importance of the Porto Rico area as the last resort by Suguio et al. (1985). for the study of its Quaternary history. Based on analysis of

POLEN COMPOSITIOM CLIMATE VEGETATION

- IIIAi.I. C4.111ATIC . IlflOAm.[AF ANO ARAUGMiiA E Iq.IJCTUATIOII TENINNI 1'O - Pom[sr PIIS£NT t;ONOlTiONI.

- TItOPiGAL 81rJilMII). - IMVMiMA i I YRANIHTHNiAL.) - CLiMATIG OPTIMUM - HMEMA,PTIRIIDmqfTTI

I - TROPICAL TO . SMiler I IUI.TIIOPlr.AL KIlO.AMID

s --L-- - WUIm .... I I I | HUtTUO ? I 1 I! I 1 I ? | .io i t I il 100 400 000 000 iO00 (On OF POI.EIm) FIG. 24. Pollen frequency, climate and vegetation during the Quaternary in the Upper Paran~ River hydrological basin (Source: Klein, 1975 and Jabur, 1993). 160 J.C. Stevaux geomorphology, sedimentology and lithofacies associations, das cascalheiras dos nos Parami e Araguam: nomenctatura ¢ provenifmcia. In: Simpfsio Regional de Geologia 5. S~loPaulo. Boletim together with palynology, t4C and TL dating (Stevaux. de Resumos. 1993), several hypothesis can be put forward as to the Braun, O.P.G. (1971). Contribuiq~lo ~ Geomorfologia do Brasil Central Quaternary evolution of the Upper Paranfi River: Revista Brasileira de Geografia, 32(32), 1-36. Cant, D.J. and Walker, R.G. (1978). Fluvial process and facies sequences in -- Two different levels of conglomerate identified as the the sandy braided South Saskatchewan River, Canada. Sedimentotogy, 'Quartzite and Agate Generations' (Fulfaro, 1974: 25, 625-648. Boggiani et al., t985) can be correlated with tectonics Drago, E.C. (1990). Hydrological and geomorphological characteristics ot the hydrosystem of the Paran~i River. Acta Limnolfgica Brasileira, lI~l. events that raised the western watershade between 57--62. Paranfi and Paraguay hydrologic basins during the Fan-el, KM (1987). Sedimentology and facies architecture of overbanK Neogene. deposits of Mississippi River, False River region, Louisiana. In: Ethridge, F.G., Flores, R.M. and Harvey, M.D. reds), Recent -- Many authors attribute to the excavation of the first order Developments in Fluvial Sedimentology. Society of Economic architectural element channel (CH) an age about at the Paleontologists and Mineralogists, Special Publication no. 39, pp. limit of the Pliocene/Pleistocene (King, 1959; Bigarella 111-120. Fernandez, O.V.Q. (1990). Mudanqas no canal fluvial do rio Parami e and Ab'Saber, 1964; Braun, 1971; Bertheleness, 1961; processos de erosio nas margens: regiio de Porto Rico. P.R. Master Fulfaro and Suguio, 1974; Suguio et al., 1984; Stevaux, dissertation, Instituto de Geoci~ncias e Ci~ncias Exatas, Universidade 1993). Several recent ~4C age determinations in samples Estadual Paulista (UNESP), Rio Claro, SP, 96 pp. Fulfaro, V.J. (1974). Dep6sitos de cascalho da bacia hidrogr~ca do rio from the channel deposits of the Paranfi River in Porto Paran~. lnstituto de Pesquisas Tecnol6gicas do Estado de S/It Paulo, Rico and Porto Primavera dam and from geomorphologic relat6rio interno s/n, 20 pp. unit Taquarupu show an age superior to 40 ka BP. This Haszendine, R.S. (1983a). Fluvial bars reconstruction from a deep, straight emphasizes the hypothesis that during the Pleistocene, channel, Upper Carboniferous coal field of Northeast England. Journal of Sedimentary Petrology, 53, 1233-1248. under predominant dry climate, the valley was filled with Haszendine, R.S. (1983b). Descending tabular cross-bed sets and boanding typical braided system and colluvium. surfaces from a fluvial channel in Upper Carboniferous coal field of Northeast England. In: Collins,on, J.D. and Lewin, J. (eds), Modern and -- Wet climatic conditions (Atlantic Climatic Optimum) Ancient Fluvial Systems. International Association of Sedimentology~ probably associated with tectonic reactivation changed Special Publication no. 6, pp. 449-456. the river channel pattern and a new valley bottom was Iriondo, M.H. (1987). A comparison between the Amazon and Paran~tRiver systems. Mitteilungen des Geologisch-Palaontologisches Instituts, generated (corresponding to the surface of the high flood Universit~t Hamburg. plain and major islands). A fluvial meandering system ltaipu Binacional (1990). Estudo sedimentomftrico no sistema de Itaipu. with large flood plain was formed at this time (6(D0--4000 Report 06/87-12/88, GEA4D0. Internal Report. BP). The sandy deposits of the ancient braided system Jabur, I.C. (1993). Anfilise paleoambiental do Quatern~'io Superior na Bacia Hidrogr~ifica do Alto Paran~i. Doctoral thesis, lnstituto de were covered by the muddy meandering deposits. Geoci~ncias e Ci~ncias Exatas, Universidade Estadual Paulista --- The recent fluvial system was reactivated probably by eUNESP), Rio Claro (SP), 184 pp. tectonic movements, creating a new terrace 3 m above Justus, J.O. (1985). Subsfdios para interpretaq~to morfogen~tica atrav~s da utilizaqfio de imagens de radar. Masters dissertation, Bahia State the present active flood plain. This terrace is flooded only University, Brazil, 204 pp. during major floods that occur cyclically every 7 years. King, L.C. (1956). A Geomorfologia do Brasil oriental. Revista Brasileira The present flood plain is 1 to 2 m above the normal de Geografia, Ant XVIII, 2, 3-48. Kirk, M. (1983). Bar development in a fluvial sandstone (Westphalian 'A'), water level and is flooded every year. This last Scotland. Sedimentology, 30, 727-742 rectivation exposed part of the ancient braided system Klein, R.M. (1975). Southner Brazilian phytogeographic features and the and thus liberated a great amount of sand probable influence of Upper Quaternary climatic changes in floristic distribution. In: Bigarella J.J. and Becker, R.D. (eds), Special Contribution, International Symposium on the Quaternary., pp. 67- 8s ACKNOWLEDGEMENTS Miall, A.D. (1977). A review of the braided-river depositional environment. Special thanks are extended to my colleagues from GEMA (Grupo de Earth Science Review, 13, 1-62. Estudos do MOo Ambiente of the University of Maringfi, Department of Miall, A.D. (1978). Fluvial sedimentology: An historical review. In: Miall; Geography), Dr lssa C. Jabur, Mantel Luiz dos Santos, Oscar V.Q. A.D. (ed.), Fluvial Sedimentology. Can. Soc. of Petrol. Geol. Memoir., Fernandez and Edvard E. Souza Filho who worked with me in all phases of 5, 1--47 this project. To CNPq, FlNEP and CONCITEC funding agencies for this Miall, A.D. (1985). Architectural-element analysis applied to fluvial research. I am also grateful to Dr Thomas R. Fairchild (University of S/to deposits. Earth Science Review, 22, 261-308. Panlo, Brazil) who reviewed the English text. To Professor Shigueo Nogueira, J. Jr (1988). Possibilidade de colmata~io qufmica dos filtros e Watanabe (University of S~o Paulo, Brazil) and Professors Mu Zhiguo and drenos da barragem de proto Primavera (SP) por compostos de ferro. Zheng Gonwang (Peking University, China) for the TL analysis. Masters dissertation, Instituto de Geoci~ncias, Universidade de S~to Paulo, Vols I and II, 229 pp. Petn. S. and Fulfaro, V.J. (1983). Geolog da Chapada dos Parecis, Matt

REFERENCES Grossg, Brasil. Revista Brasileira de Geociencias, VII, 274-282. Popolizio, E. (1975). El seudokart y su importancia en los estudios Agostinho, A.A., Borghetti, JR.. Vazzoler, A.E. and Gomes, L.C. (1991). hidrologicos del Nordeste Argentino. Centro de Geoeiencias Aplieadas. Itaipu Reservoir impacts on the ichthyofauna and biological bases for its Serie C. Investigacion n. 1, Universidad Nacional de Noroeste managements. International Workshop on Regional Approach to Argentino. Resistencia, Chaco, Argentina, 14 pp. Reservoir and management in La Plata Basin: focus on environmental Popolizio, E. (1982). Geomorphology of the Argentina Northeast. Water aspects. S. Carlos-Foz do Igua~u/Brasil and Jacireta/Argentina. International, 7, 162-177. Allen, J.R.L. (1983). Studies in fluviatile sedimentation: Bars, bar- Popp, J.H. and Bigarella, J.J. (1975). Fornm~lo de solos cenozficos do complexes and sandstone sheets (low-sinuosity braided streams) in the Noroeste do Paran~i. Anais da Academia Brasileira de Ci~ncias, Rio de Brownstone (L. Devonian), Welsh Borders. Sedimentary Geology, 33, Janeiro, 47, 465--472 (suplerr~nto). 237-293. Rust, B.R. (1972). Structure and process in a braided river. Sedimentology, Berthelenness, H. (1961). Interfer~ncia de comportamento de uma 18, 221-245. drenagem, Boletim Paranaense de Geografia, 2-3, 6-13. Santos, M.L. (1991). Facilogia e evolu~to de barras de canal do rio Paran~t Boggiani, P.C., Coimbra, A.M. and Fairchild, T.R. (1985). Seixos silicosos na regiao de Porto Rico (PR). Masters dissertation, Instituto de I The Upper Parar~ River (Brazil) 161

Geoci~ncias e Ci~ncias Exatas, Universidade Estadual Paulista Smith, N.D. (1972). Some sedimentological aspects of planar cross- (UNESP), Rio Clato (SP), Brazil, 100 pp. stratification in a sandy braided river. Journal ofSedimentary Petrology, Santos, M.L. and Fernandez, ON.Q. (1992). Minerals pesados has barras do 42, 624--634. rio Paranl em Porto Rico (PR). Anais do 37 °. Congresso Brasileiro de Stevaux, J.C. (1993). Sedimentagio e morfogenese dos dep6sitos Geologia, Slo Paulo, Boletim de Resumos, pp. 310-311. associados ~ calha do rio PatanL regiio de Porto Rico (PR). Doctoral Santos, M.L., Fernandez, O.V.Q. and Stevanx, J.C. (1989). Aspectos thesis, Instimto de Geoci~ncias, UniverSLd~_dede Sio Paulo, Sao Paulo, moffogen6ticos das batras de canal do rio Patan& regiio de Porto Rico Brazil, 200 pp. (PR). Anais 11 Congresso da Associaf~w Brasileira para o Estudo do Suguio, K., Martin, L., Bittencourt, C.S.P., Dominguez, J.M.L. and Flexor, Quaterndrio (ABEQUA), Rio de Janelro. J.M. (1985). FlutuacSes do nlvel relativo do mar durante o Quatern~mo Smith, D.G. (1976). Effect of vegetation on the lateral migration of Superior ao iongo do litoral brasileiro e sues implicaf6es na anastomosed channels of a glacial meltwater river. Geological Society sedimentagio costeira. Revista Brasileira de Geoci#ncias, 15(4), of America Bulletin, 87, 857-860. 273-286. Smith, N.D. (1971). Transgressive bars and braiding in the lower Platte Williams, P.F. and Rust, B.R. (1969). The sedimentology of a braided river. River, Nebraska. Geological Society of America Bulletin, 82, Journal of Sedimentary Petrology, 39, 649-679. 3407-3420.