lable at ScienceDirect

Journal of South American Earth Sciences 62 (2015) 218e228

Contents lists avai

Journal of South American Earth Sciences

journal homepage: www.elsevier .com/locate/ jsames

Taphonomic and paleoenvironmental considerations for theconcentrations of macroinvertibrate fossils in the Romualdo Member,Santana Formation, Late Aptian e Early Albian, Araripe Basin,Araripina, NE, Brazil

Ludmila Alves Cadeira Do Prado a, *, Priscilla Albuquerque Pereira a,Alexandre Magno Feitosa Sales b, Alcina Magn�olia Franca Barreto a

a Laborat�orio de Paleontologia, Dept. de Geologia, Centro de Tecnologia e Geociencias, Universidade Federal de Pernambuco, Cidade Universit�aria, 1235,50740-533, Recife, Brazilb Dept. de Ciencias Biol�ogicas, URCA, Campus Pimenta, 1161, 63.100-000, Crato, Brazil

a r t i c l e i n f o

Article history:Received 20 February 2015Received in revised form20 May 2015Accepted 3 June 2015Available online 5 June 2015

Keywords:TaphofaciesStormsMolluscsEchinoidsMarine transgressionEarly Cretaceous

* Corresponding author.E-mail addresses: prado.lac@gmail.com (L.A.C.D

hotmail.com (P.A. Pereira), amfsales@uol.com.br (Agmail.com (A.M.F. Barreto).

http://dx.doi.org/10.1016/j.jsames.2015.06.0050895-9811/© 2015 Elsevier Ltd. All rights reserved.

a b s t r a c t

Benthic macroinvertebrate fossils can be seen towards to the top of the Romualdo Member of theSantana Formation, in the Araripe Basin, Northeast Brazil, and can provide paleoenvironmental andpaleobiogeographical information regarding the Cretaceous marine transgression which reached theinterior basins in Northeast Brazil. We analyse taphonomic characteristics of macroinvertebrate con-centrations of two outcrops (Torrinha and Torre Grande) within the municipality Araripina, Pernambuco,in order to enhance our understanding of the Cretaceous paleoenvironment in the western portion of theAraripe Basin. At the outcrop Torrinha, proximal tempestitic taphofacies were identified. These pre-dominantly consist of ceritid, cassiopid, and later, naticid gastropods as well as undetermined bivalves.Given this lack of variability it can be deduced that there were no significant paleoenvironmentalchanges during the successive stages tempestitic sedimentation. In the Torre Grande outcrop distal toproximal tempestitic taphofacies were identified from the base to the top respectively pointing to adecrease in paleodepth. Asides from the macroinvertebrates present in Torrinha, there are also echinoidse unequivocal evidence for marine conditions. These occurrences appear to be restricted to RomualdoMember outcrops in the Araripina municipality (the Southeast portion of the Araripe Basin) confirming apreviously published hypothesis suggesting that the Cretaceous marine transgression originated fromthe neighbouring Parnaíba Basin to the west. This study identified marine molluscs of a similar age tothose in the Romualdo Member's equivalent rock units in the Parnaíba and Sergipe-Alagoas (SE-AL)basins suggesting a marine connection between these basins and the Araripe Basin during the EarlyCretaceous.

© 2015 Elsevier Ltd. All rights reserved.

1. Introduction

The Araripe Basin is the only interior basin in Northeast Brazilthat records a Lower Cretaceous eustatic marine transgression(Ponte, 1992; Ponte and Ponte Filho, 1996), which brought sea-levelto approximately 300 m above the present day (Vail et al., 1977). It

. Prado), palbuquerquep@.M.F. Sales), alcinabarreto@

is generally accepted the Romualdo Member (Santana Formation)in the Araripe Basin represents a lagoonal environment witheventual marine incursions. Together with associated occasionalstorm events, this transgression resulted in a change to the physio-chemical conditions of the region causing the widespread of mor-tality of organism (Della F�avera, 1987), for example of fish found incalcareous nodules, globally recognised for their exceptional pres-ervation (Maisey, 1991). In addition to fish, reptiles can also befound, such as turtles, crocodiles, dinosaurs, pterosaurs and vegetalremains (Price, 1959; Silva-Santos and Valença, 1968; Naish et al.,2004; Filgueiras et al., 2010; Lima et al., 2012). These taxons,

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228 219

however, do not allow any inferences to be drawn regarding thepresence of marine conditions in the area. This evidences comesfrom the distribution of gastropods, bivalves and mainly echinoids,localized at the top of the Romualdo Member, which categoricallydemonstrate the installation of a shallow marine environment inthe region (Sales, 2005).

Since the initial work by Beurlen (1963) there has been on-goingwork in the Araripe Basin in an attempt to understand the timingand palaeogeographical distribution of marine deposits and mac-roinvertebrate occurrence. Despite five decades of research, con-troversy still surrounds such questions. The presence of echinoidstowards the south-eastern end of the basin suggests a link betweenthe Araripe and Parnaíba Basins (W-NW). Berthou et al. (1990)reported the occurrence of fragmented echinoids (allochtho-nous?) in the Santana do Cariri municipality in northeasternportion of the Araripe Basin. The occurrence of autochthonousechinoids as seen within tempestites, restricted to the Araripinamunicipality in Pernambuco (Prado et al., 2013) suggests deposi-tion in distal areas of a shallow marine environment. Lithofacio-logical and temporal similarities between supposedly marineformations in Araripe and the Cod�o Formation in Parnaíba lendwait to this idea (Beurlen, 1963, 1966, 1971; Braun, 1966 apud Lima,1978; Arai et al., 1994; Sales, 2005). A connection with the Sergipe-Alagoas Basin (S-SE) has been inferred by strong regional sequencestratigraphic correlations and marine sedimentation in the Mur-ibeca and Riachuelo formations (Beurlen, 1971; Mabessone andTinoco, 1973; Brito, 1977 apud Lima, 1978; Silva-Santos, 1991;Gratzer et al., 2013). In Potiguar Basin (N-NE) strong SW orientatedfaults also seem to traverse and connect the two basins. However,marine sedimentation in the northern Potiguar Basin is Turonian inage and cannot be correlated with sediments found in the AraripeBasin (Lima, 1978; Arai, 2006).

Taphonomically, macroinvertebrates found in the Cear�a State, N/NE region of the Araripe Basin have been studied. These includeproximal and distal tempestites, primary biogenic concentrationsand transgressive lags (Sales, 2005; Soares, 2013; Prado et al., 2014).Within da porç~ao oeste da bacia, Pernambuco state, the first reportof macroinvertebrates was made by Beurlen (1962) in the munici-pality of Araripina. These included gastropods, bivalves and irreg-ular echinoids. However, taphonomic studies are extremely poorlyknown, with publishing restricted to a doctoral thesis (Sales, 2005),a bachelors degree monograph (Batista, 2011) and a single confer-ence abstract (Prado et al., 2013). The sites with macroinvertebrateaccumulations in the Romualdo Member (Santana Formation) canbe seen in Fig. 1.

Macroinvertebrates concentrations, especially articulated echi-noids in the municipality of Araripina, PE, make the southwesternAraripe Basin the most important area to study evidence of EarlyCretaceous marine transgressions in northeastern Brazil. Under-taking taphonomical work in this portion of the basin thus becomescritical in helping us understanding the regional Cretaceouspaleoenvironment.

This paper aims to understand the taphonomic aspects ofmacroinvertebrates concentrations in the municipality of Araripinain order to verify whether the tempestite model proposed for thetop of the Romualdo Member also applies to the area analysed. It ishoped that this will provide paleoenvironmental and paleo-biogeographical information of transgression marine of EarlyCretaceous in the Araripe Basin.

2. Location and geology of the Araripe sedimentary basin

The Araripe Basin falls over three state boundaries in NortheastBrazil; eastern Piauí, northeastern Pernambuco and the southernCear�a (Fig. 1). It is located above a Precambrian basement of the

Transversal Zone in the Borborema Province (Ponte and PonteFilho, 1996).

During the Late Aptian and Early Albian the following environ-mental transitions can be seen; carbonatic lacustrine, transitionalevaporates, shale and calcareous sandstones transitional to shallowmarine (Assine, 2007). In the Araripe Basin these phases representthe Crato, Ipubi and Romualdo Members of the Santana Formationrespectively (Beurlen,1971). Themajority of the RomualdoMemberis comprised of laminated shales containing a large number ofcarbonatic concretions (Fara et al., 2005). Calcareous sandstoneswith macroinvertebrates fossils are found at the top of theRomualdo Member indicating shallow marine deposition (Sales,2005) as can be seen in Fig. 2.

3. Materials and methods

The macroinvertebrate fossils of the Romualdo Member arelocated at the Torre Grande and Torrinha sites, themselves 6 kmapart, and to south of Araripina, Pernambuco.

Sampling was undertaken through the cutting of trenches andthe removal of macroinvertebrate containing blocks of sediment.The sedimentological and bioestratinomic facies of bioclastics aswell as stratigraphy and palaeoecology, were analysed in order toidentify the taphofacies (Fürsich and Oschmann, 1993). We followthe sampling strategy suggested by Kidwell et al. (2001) wherebyapproximately 120 bioclasts in each fossiliferous layer were ana-lysed, except for those layers that did not reach this value.

Only bioclasts of �2 mm were considered (following Kidwelland Holland, 1991). Sedimentological analysis, such as packing ofbioclasts was realized. For degrees of size-sorting, the bioclats weregrouped into 16 class sizes (I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII,XIII, XIV, XV, XVI) with 2mm intervals for each. The bioestratinomicfeatures analysed were: fragmentation, articulation, encrustation,corrosion and position on the layer. For palaeoecological faciesdescriptions, the bioclasts were quantified according to taxonomicclass. Where possible, the family and size were identified. Thestratigraphic features of the deposit (thickness, geometry andstratigraphic contacts) were observed.

4. Results and discussion

The macroinvertebrate concentrations in the fossiliferous Tor-rinha and Torre Grande outcrops have some similarities (seeTable 1), such as 1-politipic/polyspecific assemblies (univalve,bivalve and multielement), where specimens exhibit variation insize (gastropods) and random plan-view orientation, 2-Sharpcontacts at the concentration's base 3-absence of encrustationand corrosion.

The taphonomic features 1 and 2 are commonly associated withtempestitics events that non-selectively affected most of the pop-ulation and remobilized the sediments from the underlying sub-strate (Fursich and Oschmann, 1986; Kidwell and Bosence, 1991).Due to the absence of bioclasts imbrication, we thus interpret thesefeatures as having resulted from water turbulence.

The encrustation and corrosion are two taphonomic featuresdirectly linked to the bioclasts exposure rate in Taphonomic ActiveZone (TAZ, Davies et al., 1989). It's absence may suggest that bio-clasts are not retained in the same area for very long after theirdeaths (Speyer and Brett, 1988). These features are probably sharedwith all macroinvertebrates concentrations in the Araripe Basin, asSales (2005) obtained the same results analysing concentrations ofother areas of the basin.

Evidence of episodic sedimentation can be inferred by articu-lated and closed bivalves. In oxic shallow marine environmentsdisarticulation of these shells occur only few weeks after death

Fig. 1. Location of the Araripe Basin. Highlights are sites with macroinvertebrate accumulations in the Romualdo Member (Santana Formation). The squares represent accumu-lations analysed in previous studies (Sales, 2005; Batista, 2011; Soares, 2013; Prado et al., 2014). The stars represent the accumulations in the Araripina municipality, analysed in thiswork (Modified of Assine, 1992; Sales, 2005; Martill, 2007).

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228220

(Sch€affer, 1972). The same observation was made in the articulatecarapaces of echinoids in the Torre Grande outcrop. Echinoids areparticularly sensitive to disarticulation due to their multi-elementskeletons being easily degraded via scavenging, bioturbation anyform of agitation (Kidwell and Baumiller, 1990). It is important tonote that despite compression from the weight of overlying layers,the echinoids we find are collapsed, meaning the echinoids werearticulated when buried (Fig. 3a).

Buried articulate echinoids occur in banks within the TorreGrande and Canastra outcrops (Fig. 4), both located in the Araripinamunicipality, demonstrate that their occurrence cannot beconsidered as allochthonous, this being interpreted as a shallowmarine paleoenvironment (Beurlen, 1966). According to Kidwelland Flessa (1995) 89% of echinoids found dead, lived in sameenvironment inwhich theywere found. The same is true 80e90% ofmarine molluscs. An exception to this rule of thumb is wherebyabundant allochthonous organisms result from transport withintempestitic flows.

The fragmentation/articulation index of bioclasts and thepacking of concentrations differ within the various fossiliferouslayers allowing for the identification of taphofacies (Table 1). Forthe Torrinha outcrop ten taphofacies were identified (Tor1eTor10.See Figs. 5 and 6). In the Torre Grande outcrop there were threetaphofacies (Tg1eTg3. See Fig. 3).

Of note is the taphofacies Tor1, which contains only 1 closedarticulated bivalve and the external mould of a gastropod. The

sparseness does not allow us to establish a taphonomic signature assamples with fewer than 20 specimens do not allow for an officialclassification (Kidwell et al., 2001).

Nas taphofacies Tor2, Tor4, Tor5, Tor6 and Tor9 (Figs. 5a, c, d, eand 6c) the bioclastic packing varies from loose (15% of bioclasts)to disperse (5% of bioclasts). The concentrations are generally badlysorted. Most gastropods are found whole and bivalves are pre-dominantly found articulated and closed, except for taphofaciesTor9.

The well-preserved bioclasts, erosive base, mixture of frag-mented and whole shells badly sorted and polymodal distributionindicate that these concentrations were generated by storm waves(Fürsich and Oschmann, 1993). The absence of nesting and valveslying in a convex-up position, loose/disperse packing and the lowrate of fragmentation/disarticulation in most concentrations sug-gests that stormwaves acted without involving strong entrainment(Kidwell and Bosence, 1991).

The taphofacies Tor3, Tor7, Tor8, Tor10, Tg2, Tg3 (Figs. 5b and 6a,b, d and 3b, c, d) are generally badly sorted, with the exception ofTor3. As taphofacies principally comprise of fragmented/dis-articulated bioclasts. Sometimes bioclasts fragments are nestledtogether, where taphofacies are dense (50% bioclasts) to dense/loose (25% bioclasts). In some taphofacies disarticulated bivalvesare aligned to upwardly flexing bedding planes, reflecting possibleredeposition of sediment. This, supports the idea of settling stormflows (Toma�sových, 2006).

Fig. 2. The lithostratigraphic profile of the Crato, Ipubi and Romualdo Members (Santana Formation) with and enlargement detailing of the fossiliferous Torre Grande and Torrinhaoutcrops, Araripina, Pernambuco. The taphofacies in the Torre Grande (Tg1eTg3) and Torrinha (Tor1eTor10) outcrops are identified. Note stratigraphic correlation of taphofaciesTor7 and Tg2.

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228 221

According to Fürsich and Oschmann (1993) concentrationsgenerated by storms flows are similar to those generated by wavesof storms. However they differ in terms of the typical transportbiofabric. These densely packed concentrations, with a high frag-mented/disarticulated bioclasts index can result from proximalstormwave flows that would transport allochthonous bioclasts andincorporate themwithin the concentration (Fursich and Oschmann,1986, 1993; Kidwell and Holland, 1991).

In taphofacies Tg1 (Fig. 3a), the concentration is dispersed (5% ofbioclasts). The gastropods are found only their entirety. The equi-noids in most cases, are found collapsed. The high rate of articu-lation and high proportion matrix and the absence of featuresindicative of severe traction transportation suggest depositionbelow stormwave base level (Sim~oes and Torello, 2003). The facies

has ondular stratifications which, according to Della F�avera (2008,p. 225), are common in distal tempestites.

4.1. The macroinvertebrate Palaeofauna of the Romualdo Memberat the Torre Grande and Torrinha sites

The bioclastic accumulations at these outcrops comprise gas-tropods of the families Cassiopidae, Cerithiidae and Naticidae aswell as undetermined bivalves and irregular echinoids (Figs. 6b and3a, e).

Cassiopids are typical of Tethyan Domain fauna and in Europecorrespond to periodic marine incursions during the Lower Creta-ceous. They tended to inhabited intertidal and shallower infralit-toral zones, with bathymetries up to 50 m (Mennessier, 1984).

C-

e-ri-

Table 1Taphonomic facies descriptions for the taphofacies in the fossiliferous accumulations of the Torrinha (Tor1, Tor2, Tor3, Tor4, Tor5, Tor6, Tor7, Tor8, Tor9, Tor10) and Torre Grande (Tg1, Tg2, Tg3) sites. Total of 120 bioclasts analysedin each taphofacies, except taphofacies Tor1 (only 2 bioclasts). Values are presented percentages.

Taphofaceis Thickness(cm)

Structures Bioclasts(%)

GastropodsTot.:Ent.:Frag.(%)

Bivalves Tot.:Art./Close:Disart.:Frag.:(%)

EchinoidsTot.:Art.:Frag.:(%)

Families and size ofgastropods* (mm)

Families and size ofbivalves* (mm)

Families and size ofechinoids* (mm)

Class ofsize (%)**

Distribution insection (%)

Distribution inplain (%)

Tor1 7 Abrupt and erosive contacts. <5 Tot.: 50Ent.: 100Frag.: e

Tot: 50Art./Close:100Disart.: eFrag.: e

_ ? ? _ VII: 100 Con.: eObl.: 100Per.: e

?

Tor2 8 Abrupt and erosive contacts. 5 Tot.: 60Ent.: 70Frag.: 30

Tot: 40Art./Close:100Disart.: eFrag.: e

_ A: 10 e 20 ? _ I: 45II: 30III: 15IV: 4V: 3X: 3

Con.: 60Obl.: 40Perp.: e

Pol.

Tor3 11 Abrupt and erosive contacts. 55 Tot.: 100Ent.: 40Frag.: 60

_ _ A: 22B: 8 e 12

_ _ I: 55II: 30III: 5IV: 3V: 3X: 4

Con.: 80Obl.: 20Perp.: e

Pol.

Tor4 5 Abrupt and erosive contacts. 5 Tot.: 100Ent.: 85Frag.: 15

_ _ A: 8 e 12B: 8 e 12

_ _ I: 35II: 25III: 10IV: 5V: 25

Con.: 90Obl.: 10Perp.: e

Pol.

Tor5 23 Abrupt and erosive contacts. 15 Tot.: 80Ent.: 75Frag.: 25

Tot.: 20Art./Close:100Disart.: eFrag.: e

_ A: 10 e 30B: 5 e15

? _ I: 16II: 22III: 18IV: 22V: 8VI: 4VII: 4VIII: 4XV: 2

Con.: 40Obl.: 35Perp.: 25

Pol.

Tor6 18 Abrupt and erosive contacts. 15 Tot.: 90Ent.: 75Frag.: 25

Tot.: 10Art./Close: 80Disart.: 20Frag.: e

_ A; 8 e 12B: 5 e 12

? _ I: 22II: 32III: 18IV:16V: 8VI: 2VII: 2

Con.: 65Obl.: 30Perp.: 5

Pol.

Tor7 16 Abrupt and erosive contacts;three microstratiphic units.

25 Tot.: 70Ent.: 55Frag.: 45

Tot.: 30Art./Close: eDisart.: 20Frag.: 80

_ A: 9 e 16B: 9 e 14

? _ I: 35II: 12III: 7IV: 30VII: 10VIII: 2X: 4

Con.: 80Obl.: 20Perp.: e

Pol.

L.A.C.D

.Pradoet

al./Journal

ofSouth

American

EarthSciences

62(2015)

218e228

222

Tor8 11 Abrupt and erosive contacts;bioclast alignment.

25 Tot.: 80Ent.: 45Frag.: 55

Tot.: 20 Art./Close: 10Disart.: 30Frag.: 60

_ A: 9 e 30B: 5 e 20C: 12

? _ I: 20II: 13III: 25IV: 6V: 13VI: 13VII: 2VIII: 4X: 4

Con.: 60Obl.: 30Perp.: 10

Pol.

Tor9 4 Abrupt and erosive contacts. 15 Tot.: 70Ent.: 45Frag.: 55

Tot.: 30 Art./Close: eDisart.: 60Frag.: 40

_ A: 7 e 10B: 7 e 10C: 9

? _ I: 50II: 22III: 18IV: 4V: 6

Con.: 95Obl.: 5Perp.: 0

Pol.

Tor10 8 Abrupt and erosive contacts;bioclast alignment.

25 Tot.: 70Ent.: 35Frag.: 65

Tot.: 30 Art/Close.: eDisart.: 30Frag.: 70

_ A: 24 e 30B: 5 e 10

? _ I: 45II: 30III: 18IV: 5V: 2

Con.: 70Obl.: 30Perp.: 0

Pol.

Tg1 6 Abrupt and ondular contato;ondular stratification.

5 Tot.: 15Ent.: 100Frag.: e

Tot.: eArt/Close.: eDisart.: eFrag.: e

Tot.: 85Art.: 60Frag.: 40

A: 12C: 6 e 9

_ ? I: 10II: 10V: 20VII: 20IX: 20XII: 10XV: 10

Con.: 100Obl.: ePerp.: e

Pol.

Tg2 10 Abrupt and erosive contacts;three units microstratiphic;gradation.

50 Tot.: 80Ent.: 20Frag.:80

Tot.: 20Art/Close.: eDisart.: eFrag.: 100

_ A: ?B: 6 e 10

? _ I: 60II: 4III: 18IV: 8

Con.: 80Obl.: 15Perp.: 5

Pol.

Tg3 5 Abrupt and erosive contacts;bioclast alignment.

25 Tot.: 55Ent.: 45Frag.: 55

Tot.: 45Art/Close.: eDisart.: 45Frag: 55

_ A: 5 e 10C: 6 e 40

? _ I: 54II: 24III: 10IV: 8XVI: 4

Con.: 70Obl.: 25Perp.: 5

Pol.

Tot.: Total of individuals counted by taxonomic class; Ent.: entire individuals; Frag.:fragmented individuals; Art.: articulated individuals; Close: closed individuals; Disart.: disarticulated individuals; *relative a whole bioclasts; **relative a whole and fragmented bioclasts; Con.: concordant; Obl.: oblique; Per.: perpendicular; Pol.: polymodal; A: cassiopids; B: ceritids; C: naticids; ?: undetermined; e: absent; I: 2.0 mm to 3.9 mm; II: 4.0 mm to 5.9 mm; III:6.0 mm to 7.9 mm; IV: 8.0 mm to 9.9 mm; V: 10 mm to 11.9 mm; VI: 12.0 mm to 13.9 mm; VII: 14.0 mm to 15.9 mm; VIII: 16.0 mm to 17.9 mm; IX: 18.0 mm to 19.9 mm; X: 20.0 mm to 21.9 mm; XI: 22.0 mm to 23.9 mm; XII:24.0 mm to 25.9 mm; XIII: 26.0 mm to 27.9 mm; XIV: 28.0 mm to 29.9 mm; XV: 30.0 mm to 31.9 mm; XVI: 40.0 mm to 41.09 mm.

L.A.C.D

.Pradoet

al./Journal

ofSouth

American

EarthSciences

62(2015)

218e228

223

Fig. 3. Macroinvertebrate accumulations in the Torre Grande outcrop (taphofacies). a) Tg1 with collapsed echinoid carapace identified, b) Tg2 formed by three microstratigraphicunits (1, 2 and 3), c) Tg2 vertical cut and polished view, d) Tg3, e) View of naticid gastropods.

Fig. 4. Macroinvertebrates concentrations of the Canastra outcrop site, municipality of Araripina, PE. Highlighted are the irregular echinoids (Prado, 2015).

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228224

Fig. 5. Macroinvertebrate accumulations in the taphofacies. a) Tor2, b) Tor3, c) Tor4, d) Tor5, e) Tor6.

Fig. 6. Macroinvertebrate accumulations in the taphofacies. a) Tor7 with three tempestitic microstratigraphic units (1, 2 and 3), b) Tor8 comprising cassiopids (A) and ceritids (B), c)Tor9, d) Tor10.

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228 225

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228226

tids tend to inhabit shallow brackish water. Some genera live inopen marine coastal areas, whilst others prefer lagoons and estu-aries. Naticids live in sand or muddy-sand areas stretching from thetidal zone to medium depths (Wenz, 1938). The echinoids consti-tute an unequivocal evidence of marine conditions. This fauna isthus indicative of a shallow marine paleoenvironment.

The identified gastropods are representative of sedimentarypackages of coeval age to those in the Sergipe-Alagoas Basin (Ria-chuelo Formation) and Parnaíba Basin (Cod�o Formation). Cassio-pids are found in the Riachuelo (Maury, 1936) and Cod�o (Cassab,2003). Together with the ceritids and naticids of the RiachueloFormation (Cassab, 2003) the evidence points to a marineconnection that linked these basins during the Early Cretaceous.

Evidence of this marine connection were obtained byN�eraudeau andMathey (2000), where the Tethyan echinoid speciesPigurus tinocoi (Beurlen, 1966) and Bothryopneustes araripensisBeurlen, 1966 (Manso and Hessel, 2007) of the Romualdo Member.This strongly suggests a biogeographical propagation to the southvia the Caribbean and Central America. Arai (2014), used the Sub-tilisphaera ecozone to propose that Tethyan waters had graduallyinvaded the interior of Northeast Brazil via the S~ao Luís, Parnaíba,Araripe and Sergipe-Alagoas basins, respectively.

4.2. The paleoenvironmental interpretation of the Torrinhafossiliferous outcrop

This outcrop is approximately 1.4 m think and is formed ofcalcareous sandstones with gastropod and bivalve fossils. A total of10 fossiliferous bed were identified representing the taphofaciesTor1 e Tor10 (bottom to top of outcrop, sequentially, Table 1. Seealso Figs. 5 and 6). These layers are themselves intercalated by veryfine horizontal laminated sands, which contain no fossils (Figs. 2and 7). It is understood that the fossiliferous beds represent prox-imal storm taphofacies, whereas the very fine sand was depositedpost-storm events due to a drop in hydraulic energy.

The bioclasts correspond to gastropods in the Cassiopidae,Cerithiidae and Naticidae families and undetermined bivalves. It

Fig. 7. The taphofacies in the Torrinha outcrop, municip

can be inferred that during the macroinvertebrate sedimentationlevel at the Torrinha site, there was no significant alteration inpaleobathymetry or marine conditions in general. We deduce thisdue to the consistency is sedimentation in the proximal environ-ment and the predominance of the Cassiopidae and Cerithiidaethroughout the section, pointing towards a shallow marineenvironment.

4.3. The paleoenvironmental interpretation of the Torre Grandefossiliferous outcrop

The outcrop at this location is approximately 4 m think. The first1.5 m are comprised of laminated shales within which are foundcalcareous nodules containing fish are present (mostly the speciesVinctifer comptoni). This species is the second most frequent in theRomualdo Member, and is also found in the Sergipe-Alagoas Basinand Parnaíba Basins (Maisey, 1991). Above this is beds of calcareoussand with the fish species Beurlenichthys ouricuriensis (Figueiredoand Gallo, 2004), intercalated with very fine non fossiliferous5 cm sandstone layers. These intercalations total a sedimentarypackage of approximately 1 m in thinkness (Fig. 2). The paleo-salinity of the Beurlenichthys's habitat is unknown, given that it isalso found in the Crato Formation (Figueiredo and Gallo, 2004),considered a lacustrine deposit (Neumann and Cabrera, 1999). Inthe uppermost 1.5 m calcareous sand outcrops containing a con-centration of macroinvertebrate fossils where the taphofacies Tg1,Tg2 and Tg3 (Figs. 2 and 3) were identified. These are the same aswere seen in the Canastra site, also in the Araripina municipality byPrado et al. (2013). The taphofacies suggest that the depositionoccurred in storm flows, initially distal (Tg1), but later becomingproximal (Tg2 and Tg3), possibly related to a reduction in depthconnected to a regression.

The fossil content of this outcrop indicates that it was closer tothe origin of marine ingression and thus possessed a paleoenvir-onmentmore favourable to the establishment of an echinoid colonyin taphofacies Tg1 (Fig. 3a) and medium-sized naticids in

ality of Araripina, PE. a) Tor1eTor6, b) Tor7eTor10.

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228 227

taphofacies Tg3 (Fig. 3e). This is in addition to ceritids, cassiopidsand unidentified bivalves also present within the outcrop.

Comparing taphofacies from the Torrinha and Torre Grandeoutcrops, both occur within 3 microstatigraphic units (Figs. 6a and3b,c); taphofacies Tor7, as with Tg2. These contain mostly frag-mented bivalves and gastropods and are densely packed. These arefollowed by taphofacies generated by proximal storms (Tor8 andTg3), composed of by ceritid e naticid gastropods, which can becorrelated laterally to the same taphofacies (Fig. 2). Especially in theTor7, bioclast compaction shifts from dense to loose from the baseto the top of unit respectively. This shows a gradation in biofabric,resulting from a drop in energy and sedimentation following stormaction.

5. Conclusions

Through taphonomic macroinvertebrate analyses in two out-crops of the Santana Formation, we conclude that waves and stormflows operating in shallow marine environment were responsiblefor the last stages of the Romualdo Member's deposition in themunicipality Araripina, Pernambuco. This is in agreement withprevious research in N/NE portions of the Araripe Basin. The pale-oenvironment conditions in the Torrinha outcrop remained con-stant over time with bioclasts paleodeposition occurring inproximal areas. In contrast we observed a shallowing of deposi-tional paleodepth from the base to top of the Torre Grande outcrop,with bioclasts initially buried in distal areas and subsequentlytransported in a proximal environment.

The faunal gastropods (ceritid, cassiopid and naticid) and echi-noids suggest an Early Cretaceous marine connection existed be-tween the Araripe, Sergipe-Alagoas Basin and Parnaíba Basin withthe marine transgression in the Araripe Basin originating fromParnaíba, to the west.

This work contributes to the very few bodies of macro-invertebrate taphonomic work undertaken in this western portionof the basin. More research is needed to provide further clarifica-tion and detail regarding the taphonomic characteristics of fossilconcentrations in the Romualdo Member, as well as the paleo-environmental and paleobiogeographical aspects of marine trans-gressions in the Araripe Basin.

Acknowledgements

The Brazilian National Science and Technology DevelopmentCouncil (Conselho Nacional de Desenvolvimento Científico e Tec-nol�ogico; CNPq) for financial support (process numbers 131216/2013-9, 407148/2010-3 and 201716/2010-0). Sincere thanks to theowners of the land from where the material for this study wascollected.

References

Arai, M., 2006. Revis~ao estratigr�afica do Cret�aceo Inferior das bacias interiores doNordeste do Brasil. Geociencias 25 (1), 7e15.

Arai, M., 2014. Aptian/Albian (Early Cretaceous) paleogeography of the SouthAtlantic: a paleontological perspective. Braz. J. Geol. 44 (2), 339e350.

Arai, M., Lana, C.C., Pedr~ao, E., 1994. Ecozona Subtilisphaera spp.: Registro eocret�aceode um importante epis�odio ecol�ogico do Oceano Atlantico primitivo. Acta Geol.Leopold. 39 (2), 521e538.

Assine, M.L., 1992. An�alise estratigr�afica da Bacia do Araripe, Nordeste do Brasil. Rev.Bras. Geocien. 22 (3), 289e300.

Assine, M.L., 2007. Bacia do Araripe. Bol. Geocienc. Petrobr�as 15 (2), 371e389.Batista, M.E.P., 2011. Evidencias de dep�ositos de tempestitos fossilíferos cret�aceos na

regi~ao de Moreilandia, borda sul da Bacia do Araripe. Monografia de Graduaç~ao,Departamento de Ciencias Biol�ogicas, Universidade Regional do Cariri, p. 51.

Braun, O.P.G., 1966. Estratigrafia dos sedimentos da parte inferior da regi~ao Nor-deste do Brasil (Bacias de Tucano-Jatob�a, Mirandiba e Araripe). Bol. D.N.P.M. Div.Geol. Miner. 236, 1e15.

Berthou, P.Y., Viana, M.V., Campos, D.A., 1990. Coupe da La Formation Santana dansLe secteur de “Pedra Branca” (Santana do Cariri) (Bassin D’ Araripe, NE duBr�esil). Contribuition a l’ �etude de La sedimentologie et des paleoenvironne-ments. In: Simp�osio Sobre a Bacia do Araripe e Bacias Interiores do Nordeste, 1.Atas, pp. 173e1991.

Beurlen, K., 1962. A geologia da Chapada do Araripe. An. Acad. Bras. Cienc. 34 (3),365e370.

Beurlen, K., 1963. Geologia e estratigrafia da Chapada do Araripe. In: CongressoNacional de Geologia, 17. Anais, vol. 1, p. 47.

Beurlen, K., 1966. Novos Equin�oides no Cret�aceo do Nordeste do Brasil. An. Acad.Bras. Cienc. 38, 455e464.

Beurlen, K., 1971. As condiç~oes ecol�ogicas e faciol�ogicas da Formaç~ao Santana naChapada do Araripe (Nordeste do Brasil). An. Acad. Bras. Cienc. 43, 411e415.

Brito, I.M., 1977. Hist�oria geol�ogica das Bacias Sedimentares do Nordeste do Brasil,Anais da Academia Brasileira de Ciencias 48 (3), 463e474.

Cassab, R.C.T., 2003. Paleontologia da Formaç~ao Jandaíra, Cret�aceo Superior da BaciaPotiguar, com enfase na Paleobiologia dos gastr�opodos. Universidade Federal doRio de Janeiro, p. 184. Tese de Doutorado.

Davies, D.J., Powell, E.N., Stanton Jr., R.J., 1989. Taphonomic signature as a function ofenvironmental process: shells and shell beds in a hurricane-influenced inlet onthe Texas coast. Palaeogeogr. Palaeclimatol. Palaeoecol. 72, 317e356.

Della F�avera, J.C., 1987. Tempestades como agentes de poluiç~ao ambiental e mor-tandade em massa no passado geol�ogico: caso das formaç~oes Santana (Bacia doAraripe) e Irati (Bacia do Paran�a). Bol. Geocien. Petrobras 1 (2), 239e240.

Della F�avera, J.C., 2008. Ambientes marinhos rasos. In: Silva, A.J.C.L.P.,Arag~ao, M.A.N.F., Magalh~aes, A.J.C. (Eds.), Ambientes de Sedimentaç~ao Sili-cicl�astica do Brasil, Beca, p. 343.

Fara, E., Saraiva, A.A.F., Campos, D.A., Moreira, J.K.R., Siebra, D.C., Kellner, A.W.A.,2005. Controlled excavations in the Romualdo Member of the Santana For-mation (Early Cretaceous, Araripe Basin, northeastern Brazil): stratigraphic,palaeoenvironmental and palaeoecological implications. Palaeogeogr. Palae-oclimatol. Palaeoecol. 218, 145e160.

Figueiredo, F.J., Gallo, V., 2004. A new teleost fish from the Early Cretaceous ofNortheastern Brazil. Bol. Mus. Nac. Geol. 73, 1e23.

Filgueiras, C.F.C., Moura, T.R., Oliveira, T.R.S., Ruano, R., Silva, M.C., Barreto, A.M.F.,Oliveira, E.V., Bittar, S., 2010. Invent�ario do Patrimomio Paleontol�ogico doCret�aceo Inferior da Regi~ao do Araripe Pernambucano. In: Congresso Brasileirode Geologia, 45. Anais. CDRoom.

Fürsich, F.T., Oschmann, W., 1986. Storm shell beds of Nanogyra virgula in the UpperJurrassic of France. Neues Jahrb. Geol. Pal€aontol. Abh. 172, 141e161.

Fürsich, F.T., Oschmann, W., 1993. Shell beds as tools in basin analysis: the JurrasicKachchh, western India. J. Geol. Soc. 150 (1), 169e185.

Gratzer, R., Neumann, V.H., Vortisch, W., Rocha, D.E.G.A., Bechtel, A., 2013. Stableisotopes of organics and inorganics, clay mineralogy and chemical environmentof an Aptian lacustrine sucession in northeastern Brazil. In: Bojar, A.V., Melinte-Dobrinescu, M.C., Smit, J. (Eds.), 2013. Isotopic Studies in Cretaceous Research.Geological Society, London. Special Publications, 382. First published onlineMay 14, 2013. http://dx.doi.org/10.1144/SP382.4.

Kidwell, S.M., Baumiller, T., 1990. Experimental disintegration of regular echinoids:roles of temperature, oxygen and decay thresholds. Paleobiology 16 (3),247e271.

Kidwell, S.M., Bosence, D.W., 1991. Taphonomy and time-averaging of marine shellyfaunas. In: Allison, P.A., Briggs, D.E.G. (Eds.), Taphonomy: Releasing the DataLocked in the Fossil Record. Plenum Press, pp. 115e209.

Kidwell, S.M., Flessa, K.W., 1995. The quality of the fossil record: populations,species, and communities. Annu. Rev. Ecol. Syst. 26, 269e299.

Kidwell, S.M., Holland, S.M., 1991. Field description of coarse bioclastic fabrics.Palaios 6 (4), 426e434.

Kidwell, S.M., Rothfus, T.A., Best, M.M.R., 2001. Sensitivity of taphonomic signaturesto sample size, sieve size, damage scoring system, and target taxa. Palaios 16,26e52.

Lima, F.J., Saraiva, A.A.F., Say~ao, J.M., 2012. Revis~ao da paleoflora das Formaç~oesMiss~ao Velha, Crato e Romualdo, Bacia do Araripe, Nordeste do Brasil. Estud.Geol. 22 (1), 99e115.

Lima, M.R., 1978. Palinologia da Formaç~ao Santana (Cret�aceo do Nordeste do Brasil).PhD thesis. Universidade de S~ao Paulo, p. 337, 27 plates.

Mabesoone, J.M., Tinoco, I.M., 1973. Paleoecology of the Aptian Santana Formation(Northeastern Brazil). Palaeogeogr. Palaeclimatol. Palaeoecol. 14, 97e118.

Maisey, J.G., 1991. Santana Fossil: an illustrated atlas. T.F.H. Publications, NeptuneCity, New Jersey, p. 459.

Manso, C.L.M., Hessel, M.H., 2007. Revis~ao sistem�atica Pygidiolampas araripensis(Beurlen, 1966), (Echinodermata: Cassiduloida) da Bacia do Araripe, Nordestedo Brasil. Geociencias 26 (3), 271e277.

Martill, D.M., 2007. The age of the Cretaceous Santana Formation fossil KonservatLagerst€atte of north-east Brazil: a historical review and an appraisal of thebiochronostratigraphic utility of its palaeobiota. Cretac. Res. 28, 895e920.

Maury, C.J., 1936. Cretaceo de Sergipe: Brasil. Serv. Nac. Geol. Min. 11, 283, 28 pls.Mennessier, G., 1984. Revision des gasteropodes appartenant �a la famille des Cas-

siopidae Kollmann (¼ Glauconiidae Ptchelintsev). Trav, vol. 1. Dep. Geol. Univ.Picardie, Amiens, p. 190, 29 pls.

Naish, D., Martill, D., Frey, E., 2004. Ecology, systematics and biogeographical re-lationships of dinosaurs, including a new theropod, from the Santana Forma-tion (?Albian, Early Cretaceous) of Brazil. Hist. Biol. 16, 57e70.

L.A.C.D. Prado et al. / Journal of South American Earth Sciences 62 (2015) 218e228228

N�eraudeau, D., Mathey, B., 2000. Biogeography and diversity of South AtlanticCretaceous echinoids: implications for circulation patterns. Palaeogeogr.Palaeoclimatol. Palaeoecol. 156 (1), 71e88.

Neumann, V.H., Cabrera, L., 1999. Una nueva propuesta estratigr�afica para La tec-tono secuencia post-rifte de lacuenca de Araripe, Noreste de Brasil. In: Simp�osioCret�aceo Brasileiro, 5. Boletim de Resumo, pp. 279e285.

Ponte, F.C., 1992. Origem e evoluç~ao das pequenas bacias cret�acicas do interior donordeste do Brasil. In: Simp�osio Sobre as Bacias Cret�acicas Brasileiras, 2.Resumos Expandidos, pp. 55e58.

Ponte, F.C., Ponte Filho, F.C., 1996. Evoluç~ao tectonica e classificaç~ao da Bacia doAraripe. In: Simp�osio Sobre o Cret�aceo do Brasil, 4. Boletim, Rio Claro. UNESP,pp. 123e133.

Prado, L.A.C., Pereira, P.A., Barreto, A.M.F., Sales, A.M.F., 2013. An�alise tafonomica daconcentraç~ao de invertebrados f�osseis, sítio Canastra, Araripina, Formaç~aoRomualdo, SW da Bacia do Araripe. In: Congresso Brasileiro de Paleontologia,23. Boletim de Resumos.

Prado, L.A.C., Pereira, P.A., Sales, A.M.F., Barreto, A.M.F., 2014. An�alise tafonomica etaxonomica da concentraç~ao de invertebrados f�osseis do topo da Formaç~aoRomualdo, Cret�aceo Inferior da Bacia do Araripe em Araripe, Cear�a (CE). Estud.Geol. 24 (1), 53e64.

Prado, 2015. Tafonomia das concentraç~oes de macroinvertebrados f�osseis da For-maç~ao Romualdo, Araripina, PE e consideraç~oes paleoambientais. UniversidadeFederal de Pernambuco, Recife, p. 74. Dissertaç~ao de Mestrado.

Price, L.I., 1959. Sobre um crocodilídeo notossuquio do Cret�acico Brasileiro. Bol. Div.Geol. Mineral. Rio J. (Bras.) 188, 56.

Sales, A.M.F., 2005. An�alise tafonomica das ocorrencias fossilíferas de macro-invertebrados do Membro Romualdo (Albiano) da Formaç~ao Santana, Bacia do

Araripe, NE do Brasil: significado estratigr�afico e paleoambiental. Universidadede S~ao Paulo, S~ao Paulo, p. 160. Tese de Doutorado.

Sch€affer, W., 1972. Ecology and Paleoecology of Marine Environments. University ofChicago Press, Chicago, p. 450.

Silva-Santos, R., Valença, J.G., 1968. A Formaç~ao Santana e sua Paleoictiofauna. An.Acad. Bras. Cienc. 40 (3), 339e360.

Silva-Santos, R., 1991. F�osseis do Nordeste do Brasil: paleoictiof�aunula da Chapadado Araripe. Departamento de Biologia Animal e Vegetal, Universidade do Estadodo Rio de Janeiro, Rio de Janeiro, p. 64. Tese de Doutorado.

Sim~oes, M.G., Torello, F.F., 2003. Modelo de tafof�acies para os moluscos bivalves doGrupo Passa Dois (Formaç~oes Serra Alta, Teresina e Corumbataí), PermianoSuperior, Bacia do Paran�a, Brasil. Rev. Bras. Geocienc. 33 (4), 371e380.

Soares, R.C., 2013. Genese dos níveis coquin�oides do Membro Romualdo, Formaç~aoSantana na porç~ao central e leste da Bacia do Araripe. P�os-graduaç~ao emGeologia, Universidade Federal do Cear�a, p. 76. Dissertaç~ao de mestrado.

Speyer, S.E., Brett, C.E., 1988. Taphofacies models for epeiric sea environments:Middle Paleozoic examples. Palaeogeogr. Palaeoclimatol. Palaeoecol. 63,225e262.

Toma�sových, A., 2006. Linking taphonomy to community-level abundance: insightsinto compositional fidelity of the Upper Triassic Shell concentrations (EasternAlps). Palaeogeogr. Palaeoclimatol. Palaeoecol. 235, 355e381.

Vail, P.R., Mitchum, R.M.J.R., Thompson, S., 1977. Seismic stratigraphy and globalchanges of seal lavel, Part 4: global cycles of relative changes of sea level. In:Payton, C.E. (Ed.), Seismic Stratrigraphy e Applications to Hydrocarbon Explo-nation, pp. 83e97.

Wenz, W., 1938. Gastropoda Teil I: Allgemeiner Teil und Prosobranchia. In:Schindewolf, O.H. (Ed.), Handbuch der Pal€aozoologie, p. 948. Band 6, I. Berlin.