Upper miocene planktonic foraminifera from Algarve. Chronostratigraphical implications

pp.199-208 .. ·4 Figs.,·1PI.

Upper Miocene planktonic foraminifera from Algarve.

Chronostratigraphical implications

Paulo Legoinha

Work supported by the Project "Studies on Portuguese Paleontology (Post-Paleozoic)"(POCTl/CYT/36351/99-00)

Centro de EstudosGeolegicos(FCTIMCT),Universidade Nova de Lisboa, Faculdadede Ciencias eTecnologia,Quintada Torre,P-2825-114 Caparica,Portugal;pal@fct.unl.pt

Abstract

Key-words: Planktonic foraminifera; biostratigraphy;isotopic ages;chronostratigraphy; Upper Miocene; Algarve (Portugal). New data on the planktonic foraminifera from the Upper Miocene Cacela Formation and Mem Moniz spongoliths are presented. The coiling type of Globorotalia menardii from Cacela and Quelfes and the occurrence at Quelfes ofG.miotumida allow correlation with the bio-events Ito 3 (7,512 to 7,24 Ma; Sierro et al.,1993; 2001) that have been recognized in the Guadalquivir Basin (Spain). The presence of Neogloboquadrina acostaensis and N.humerosa at Mem Moniz points out to the Upper Miocene (Tortonian,upper N16,or even NI7).Mem Moniz spongoliths are correlated with the Cacela Formation.

Some87Srj86Sr isotopic ages of mollusc or foraminiferashells don't fit well with finer biostratigraphic record and present wide error margins.

Resumo

Palavras-chave: Foraminiferos planct6nicos; biostratigrafia; idades isot6picas; cronostratigrafia; Miocenico superior; Algarve (Portugal).

Sao apresentados novos dados acerca da biostratigrafia do Miocenico superior do Algarve (Formacao de Cacela e espongolitos de Mem Moniz).Os foraminiferos planct6nicos de Cacela e Quelfes,em especial0tipo de enrolamento de Globorotalia gr.menardii e a ocorrencia deGloborotalia miotumida(em Quelfes) permitem correlacoes com os bio-eventos 1 a 3 caracterizados na Bacia do Guadalquivir (7,512 to 7,24 Ma;Sierro et al., 1993;2001). Neogloboquadrinaacostaensis e Neogloboquadrinahumerosanos sedimentos de Mem Moniz permitem data-los do Miocenico superior (Tortoniano, parte superior de N16 ou mesmo N17) e correlaciona-loscom a Formacao de Cacela.

Verifica-se desfasamento entre a inforrnacao biostratigrafica, mais fina, e datacoes87Sr/86Sr, que evidenciam grandes margens de erro.

Introduction

A comprehensive study ofthe chronostratigraphy ofthe Miocene of Portugal has been carried on. A synthesis on the Neogene ofAlgarve has been presented (Paiset ai.,2002).

The author has studied the Miocene planktonicforaminifera from the Lower Tagus Basin and Algarve (Legoinha, 200 I). In this paper new data are presented on planktonic foraminifera from the Upper Miocene ofAlgarve, especially from Cacela Formationand Mem Moniz spongoliths.

Ctsncias do Term(UNl.),15

TheCacelaFormation (AntunesinRibeiroet 01.,1979) isexposedineastem Algarve(Cacela,Quelfes).Basallevels areconglomcrates and limeston es with pebbles. Upwards, there are muddyorcalcareous,oftenglauconite-richsands. This Formationcontacts by ang ular unconform ity with theTriassicand bydisconformity withtheLowerto Middle Miocene, Lagos-PortimaoFormation.

Whi te spongo li ths with diato m s , cal car eou s nannoplankton,foramini fera, ostracodaand fishesoutcrop at MemMoniz (Es pcngolitos deMemMoniz;Romariz

et

al., 1979) .Thesedepositsfilla tectonicdepre ssion .The concerned unit was ascri bed to the Serrava lian or Tortonian . However,severa l different age values had been proposed.Chronology can be sett lednow.Sediments like theseareunknown else whe re in Portugal.

The aimsofthis studyare:

a) toreviewthepublished data concerning the planktonic biostratigraphy ofCace la,Quelfes and MemMoniz; b)to discu ss new planktonic foraminifera data and

"SrfMSr ages;

c)toimprove theUpperMiocen e chronostratigraphic knowledgeoftheAlgarve;

d) to establish correl ationswiththebio-events defin ed in the GuadalquivirBasin (Sie rroetal.;1996). Samples for foraminiferal study were disaggr egatcd withaHP 2solution, andwas hed in a 125urnsieve.

Ca

cela

Locatio n

Outcropsnear Cacela(Fig.I).GPScoordinates:N 37" 09' 46",W 7"32' 48,6".The upperpartcanbeobserved at the localitynamed Fabrica.

Geologicalsetting

Conglomerates and fine yellow ish-gray sands tones outcropat Ribeirade Caccia, corresp onding to thebasal levelsofthe Caccia Formation,Lower membe r.AtFabrica,

there arc fine yellowis h-orange sands intercalated with levelsofcarbonate con cretions,theupper memberofthe same Format ion (Antuneset01.,198 1).

Cacela yieldedtherichestandbestpreservedMioc ene mollus k faun ainPortugal. This faunawas describ edby

Perei rada Costa (1866; 186 7), Cotter (1879;inDollfuset 01.,1903- 1904 ;inCho ffat, 1950), ChavaninBour cart& Zbysz ewski(1940),Frencix (1957)andBrebion(1957 ). Inthe last30years,asystematicstudyoftheAlgarve's Neogenehavebeencarriedon by researchers ofthe Centro de Estudos Geologicos, often in co lla b ora t ion with forei gn colleagues. The knowled ge on paleont ol ogy, stra tigraphyandchronologyhasbeenimpro ved(essential data concerning Cacel a,Antuneset01.,1981;Antuneset al., 1990, 1997; Gonza lez-Delgado etal., 1995;Pais et 01. 2000;G onzalez-Delgado & Civ is, 2000 ; Civis et al., 2000 ).

Fig.I - CacetaFormation (Geological Map ofAlgarve,1:100000; Manuppella,1992):RibciradeCacclaandFabricaoutcrops.

Bizon (inAntuneset aI.,1981)foundGlobigerinoides extremus, Globorotalia

aff

conomiozea , Globorotalia pseudomiocenica, Globotalia menardii, Globo rotalia acostaensls(sinist. ) andGloborotaliahumerosa(sinist.) that indicatethetop ofN I6or, probably, N17.

Sicrro (inAntunes et aI., 1990) iden tified abundant planktonic foraminifera at

Fa

b

r

ica,

among others Gtob ige rino ides extremus, Globigerino ides seigliei e Neogloboquadrinaacostaensis(sinist.) .Thepresenceof the benthicSp irop leclamminacarinate,which disappears inthebasalMessini an,wasremarked.The foraminiferal assemblagepointsoutto theUpperTortonian.

According to Nascimento (in Antunes et al., 1981), theOstracoda indicatea Messinianage.

PlanktonicForaminiferaand biostrat igraph icanalysis Thesamples RibciraCac ela 2 and Fabri ca 2(Fig .2) gave additionalimportantdata.

Ribeira Caeela 2 yielde d sinistral men ardi form Globorotalia. In the Guadalquivir Basin , Sierro (1985) and Sicrro et al. (1993) charac terize d a succession of bio-events . The first one is the sh arp reduction of Globorotalia menardii group I (sinis t.). The sec ond one is marked by the appearance of Globo rotalia menardii gro up II (dext. ). Bet ween these events, the temperate waters of North Atlantic and Mediterranean were almost deprived of keeled Globorotalia (Sie rro

e

t

a/., 199 3,p.l4 3).

Fab rica 2 yielde d a rich and diversified plankt onic assemblage, that does not include keeled Globoro talia. This assemb ladge comprises (Antunes et 01., 1990): Globigerinabulloides,Globtgerl naapertura,Globigerina dr uryi, Globigerinita glutinala, Glo b igerinoides bulloideus,Glohigerinoides extremus, Globigerinotdes seigliei,Globigerinoidesimmat urus, Orbulina universa, Orbulina su tur a lis, Glo b ig erina quinq ue lo b a , Globoq ua drina globo/ a, Glo borotalia scitu la, Neogloboquadrinaacostaensis(sinist.).

a:

In

o

z

o

a:

:r:

u

m

10

Cace

la

sec

tion

..

.

: ~

.

..

.... ..-

.

.. .... ...-

.

•• •• •• M _ •• •• • • • • VI

'"

c.

E

'"

VI

Cienciasda Terra(UNLJ, 15

Li

t hostratigra phy

Yellowi sh sandstone.

~

N

1-

--'--'--

----'----1~

G)

...

CIl C Q.

.!!!

Q. c::: ::J 0

I'-t::

~

o

Z

I-

_...

CIl Q. Q. ::J

Tri

assic

co

0> Z

o

co

u .;: .0

'

co

U. 5

co

Qj

o

co

U CIl "C

..

.0 ~ .. ••••..- •••• - o.

--

_{.. ....}

- _

_.....

_-

.

_

....

_.

-;-.: -;-.:..: -..-_ -4

:

:

~~··· ri~:a::

..

~ .:'.:'.:'-'~'-"-r.:'. -3 ..:~:.~:.~:

..

:

..

::.

.... .. .. ... ...:... -2 :: :::::..::..::..::..::..:: -1

.

... ..

.

. ..

.

.

.. ..

...,-

.

...

.

.

.. .

.

..

..

.

.

.. ..

-

.

...

.

.. .

. .

. .. .

.

.

. .

.

..~_....'.:::..!:-_....='a;o_-, "

_.

.

Fine ,yellowish-orangesandstone with carbonate concretions.Scarce fossils.

Fineyellowish-graysandstoneswith abundant foraminifera.bryozoa,bivalves,gastropods and fishes.

5.7

{+3

.9-

1.1)Ma

Fineyellowish-grey sandstone.

Conglomerateswrth abundant fossils:mostly tarqe-sized molluscs,cirripeds.

c:::

o

:;::

co

E

...

o u,

co

fl

III U

Fig. 2 - Cacelasection:chronostratigrap hicframewo rk; correlation withbioeventsfrom the Guada lquivir Basin

andI7Srl'6Sr ages.

Cacela2 and Fab rica 2 ageis betwee n that of the events 1and2 ofthe Guadalquivir Basin (respectively7,512and 7,35Maastronomicages; Sierroetal.,2001).

Iso top ic ages

17SrJ'6Sr age ofa bivalvemolluscgave 5,7 (+3,9 -1,1) Ma . Th is age seems too young in compariso n wit h biostrat ig raphic data.Furthe rmore themargin oferroris very wide.Thiscouldsuggestthat the calibration curveis not wellestablished forthis spanoftime ,

Que lfes Locatio n

Samples were collected at some outcropsnear Quelfes (Fig.3).GPS coordinates:N 37°03'18,3";W 7°49' 52,6".

Fig.3-Quelfes(Geological Map of Algarve,1: I00 000; Manuppella,1992):the arrow points outto the locationof the

CienciasdaTerra(UNL).15 Geologicalsctt ing

San d s and marl y si lts, often wi th bio tur ba tion structures, are exposed. A glaucon ite-rich level was reco gnisedin theupperpart.Basal bedsare conglomerat ic limeston eswithsiliceo uspebblesand limestone boulders. These deposits belong to the Cacela Format io n.

Neogloboquadrina acostaensis (sinist. predomina nce ),

Globigerinoides extrem usandsome keeledGloborotalia

(dext. pred ominance)pointouttothe UpperTortonian . Sierro (ill Antuneset al., 1990) stressed the possibility that the upper levels could be Mes sinian in age. In comparisonwithGuada lquivirBasin,the ageofconcerned deposits is so metime betweenevent s2and 3(Sierro,1985 ; Sierro et01.,1993).

Pla nktonic Fora m in iferaand biost r a tigr a phic ana lysis

Samples Q2 and Q4 are the richest in plank tonic fora mini fers, while Q3 is the les s rich (F ig.4). The following species wereidentified:

Q

1

-

Dentoglobig erina altispira, Globigeri noides

bullo ide us,Globigerinoides conglobatus ,Globigcrinoides ex/remus, Neoglobo q ua drina humeros a, Orbulina

universa.

Q2- Dentoglobig erinaaltisp ira , Globigerina bulloides,

Glob igerina praecalida , Glob ig eri noides bulloideus,

Globigerinoidesconglobatus, Globigerinoides extremus,

Globig erinoides seigliei,Neogloboqua drina humerosa,

Orbulinasuturalis, Orbulinaunivers a.

Q3 -

G

lob i

ge

rin

oides b

ull

o

id

eus, G

lo b

ige

ri

n

o

i

des

seigliei, Orbulinasuturalis, Orbulina universa.

Q4 - Globigeri na bulloides, Globigeri na conc ina,

Globigerino ides bulloideus, Globig erinoides elongatus,

Globigerino ides extre mus, Glo bigeri no ides seigliei,

Globo rolalia gr. men ardii (de xt.) , Globorota lia mi oturnl d a ; Neogloboqu adrina acostaens is , Neogloboquadrina humerosa, Orbulina universa.

Q5 - Globig er ina bulloides, Glob iger ina druryi,

Globig erinoides bulloideus , Globigerinoides trilob us,

Globorotaliaconomiozea, Orbu lina sutura lis, Orbulina

universa.

Biostratigraphi cinterpretat ionis shown(Fig.4). In the lower part,

N.

humerosa e G conglobat us ind ica te the Upper Tortonian (probably N17). In the upperpart G

mi

otum

i

da

and G.

co

no mioz

e

a

point out to the Messinian (N 17). Glo bo rota lia gr. men ard ii (dex t.) is still present in the Q4 sample. This suggests that the concernedlevelsmay be corre latedtotheevent3 of the Guad a lquivir Bas in, marked by the repl acem ent

of the G menardii group by the G miotumida group

(Sierro et01., 1993).

Isotopicages

Shell s of mollu scs from different Icvels were dated

"Sr/"Sr: 5,3 (+4,3-0,7 ) Ma , 5,2 (+4,4-1 ,1) Ma, 5,2 (+4 ,4 -0 ,6 ) Ma. Thes e agcs seem too much younger than the expected age 7 (+1- 1) Ma as established by Berggren et01.(1995) forN17. Let us recall that KlAr gla uco nite age for two samples from Luz de Tavira (co rrelative of Quelfes) is6,88±0,4Maand 7,03±0,4Ma (Antu nes et01.,1986).Age of event3is 7,24Ma (Sierro

et01.,2001).

Me

m

Mo

n iz

Locat io n

Outcro ps at Me m Moniz (Fig . 5) that border the national road EN39 5.

Gcologica lsetting

With ishsedime ntswithsome teleosteanfishremnants (bo nes and scales) and high abundance ofmicrofossil s (sp onge skeleta l elemen ts, diatom s , calcareous nannofossils,plankton icforaminiferaandostracods).The lowercon tactisan angularunconformityover Cretaceous

units (Romariz et01., 1979;Antunes et01., 198 1).The stratig raphic position has been object ofcontrov ersy.

Sed imentslikethese are unknownelsew hereinPortugal. In Spain, similar sediment s are known to overlie the Guadalquiv irolistostrome.

Prates (ill Romariz et01., 1979) ascribed the Mem Mo niz dep osits to the Up per Burdigalian or Lower Langh ian(N8 orN9)on plank tonicforaminifera.

According to Bizon (ill Antunes et 01., 1981 ),

Globorotalia acostaens is (sinis tra l) po in ts out to a Tortonian,N16age.

Sierro(ill Antunes et01.,1990)stress edthatthepr e-domina nceofGlobigerinabulloides inasso ciation with

Neog

lobo qua d

ri n

a a

cos

t

a ensis

,

Gl

ob ig erino id es

bulloideus ,Globigerina druryi, Globigerin aquinqueloba andGlobigerinitaglutina taindicates atleast N16.

Thes e sed i me nts were ascrib ed to the Midd le Serrava lli a n (C N 5 a) on calcareo us nan no p lankt o n (Cachao, 1995).

"Srl" Srage on planktic foram inifera was obtained:

12.5(+0.7-1.7) Ma,Upperto Middle Serrava llian(Ant unes

et01.,1997).

PlanktonicForaminifera and biostratigraphicanalysis

Four samples were stud ied. The plankton ic

foraminifera frequen ce decreases from the lower tothe midd lepart ofthe success ion.They are more abun da nt again in theupperpar t.Foraminiferaarewell preserved but are smallerthan usual.

The foll ow ing species were ide ntified : Globigerina angustiumbiltcata , Globigeri na bulloides, Globigerina conc ina, Globigerina druryi, Globigerinafalconensis,

CicnciosdaTerra(UNLi.15

>-

P

lank

t

on

ic

F

oram

i

nif

e

ra

I n,

>-

"

«

_J: $ _;i

a:

e, .!!] CD

o

«

:g

CD :2-I-

a:

_s

CD

e

:e

s

-c

C:l

_'"

_"

CD CD c

a:

_i=

8

E _~ E c:

_~

_{~ (jj} iii E I-

«

CD .c;:::> _.~ Jg

"

_E .Q

'"

~

E

.,

.!!l

_'"

(/) C/) CD CD

_ill

"

8

7

S

r/

86

Sr

al

-Q

uelfes

₀

a:

.~

_~

CD 0 _C

'"

Q)

_e;,

_{.Q c:} ~ - ' I-

_'"

I

;;; Q)

'"

C:i. Z '0

~

E

8

..

'"

sec

t ion

(J) CD

s

_'5

>

c

_E

₀

0 ::> ~ ~ ~

ages

Q) _OJ -'"

2'

0- CT

b

0

'"

a:

0

s

.~

a

s

~

iii

g

:E (J) _{I III} -c

"

_~

e

."

in

I-0

Q

_{8' 8'}

Q

..,

.~ .

..,

~

.8

..,

(

Mal

.,

:::J

~

'"

~

~

@

Q

s

Q Q

_e

\:J \:J \:J

~

-.

-

.

_QS

I

·

1-

-

_{5.2 (}

₊

_4.4-0

_.6)

~

....

,

l<... .

..

.

z

-

_-

_'.

«

--r-

z

-C/)

I I I I I I

-~: ::::: : :::::

-.

-

Q4

C/)

·

:<?:':i:~ ~ ~.

w

0

~ ::-i-:-:

:2

10 -

~.

..

'

.

.

-+-7

.

24

Ma

-

-

--

:: :~:::::: :~ : :

:+

I

.

-;-

.

-

:

-.

-

Q3

-7--

.

;. .~

.

·

'

-'m

'

:

-t-:

"

'~

I'-:: '

~t:~,

:-'

,

~

-

i

-

\ ;

:-;L..~

z

:

.

:-

.

-

.

:...;-:

.

·

:-

:-

t

..

.

-,,-,-

t

J-j.•:.

:--

'

1

-:

1

:-

"

f

-:

~j~<ft+

z

I

I

I

It-

5

.3

::::=t. :::: : :

-.

-

Q2

«

.

(

+4.3

-0.7)

5

_-:-r:-:

_~:t:'"V;~

-tW~*

z

-

0

-:-t:

~(~ ::

i

:-

I-a:

:::

.:[;

:

+r;:

:

₀

:

j;

-

:

:-:~-::-:~

I-:

: :+: :r:~ :

-.

-

Q1

w

a:

_c,

I

_I

..

-:-t::.;r..;:;i:

c, : )

:::+4-.:1:

.

:

0

_:1::~::::

:><:

o-<0

-Z

Fig.4.Chronostratigraphic framework of the Quelfessection; occurrence of planktonicmarkers, correlation with

CienciasdaTerra (UNLJ, 15

MemMoniZ

spongoIiths:

sampled

_ crops

Isotop icages

The "Srl'''Sr plank to nic fora m inife ra she ll age is seemingly too old- 12.5 (+0 .7·1.7) Ma (Midd letoUpper Serravallian).Thisageisnotsupported bybiostra tigraphic

informa tion and should berejected.

Con cl us io ns

I) Planktonic foramin ifera andespeciallythe coilingtype of Globorolalia menardii group and the occurrence of

Globorotalia miotumidaat Quelfes allowcorre lationwith the I to 3bio-eventsin theGuadalq uivirBasin (Sierroet

01., 1993).

2) Cacelaand Fabrica maythus be dated from thetime spanbetweenGuada lquiv ir basin'sevents Iand 2 (7.512 and 7.35 Ma; Sierroet01.200 I).

Fig.5 • Spongolithsat Mem Moniz (Geological Map of Algarve, 1:100000; Manuppella, 1992).

Globige rinella aequilateralis, Globigerinoides bulloideus ,

Globoquadrina baroemoenensis, Neogloboquadrina

acostaensis (sinist.), Neogloboq uadrina humerosa

(sinist.).

N. acostaensisandN.humerosapoint out to uppermost N 16 or even N 17. This age should be older than 6 Ma (Upper Messinian),as theN.acosta ensiscoilingdirection changed to dextral coiling. The absence of cari nate

Globorotalia do not allow a bet ter biost ra tigra ph ic

accuracy.

The pre sen c e of Glob ig erina drury i cou ld be pro ble ma tic. The last appeara nce dat um is gene ra lly

regarded as Upper Serrava llian (NI4),butSierro(1984) has shown that it still occurs in the GuadalquivirBasin in the Upper Miocene and LowerPliocene.

This assemblage undoubtedly is Upper Miocene in age. Hence the Mem Moniz sed ime nts are of the some age as the CaccIa Formation. The correlation between Quc lfes (lowe r part) and Caccia is most likely. This chrono logy isncarthesameasthat ofsimilardeposits in peri-medi terranean area, i.e. Spain, Italy and Argelia.

References

3) At Quelfes, Globorotalia miotumidaand G menardii

(dext.) may be correlatedto event 3 (7.24 Ma).

4) In the upper part of the outc ro p , Globoro talia

cono miozea suggests a Messinian age (FAD 7.12 Ma;

Berggren etal., 1995).

5) Glauconite KiAr ages from Luzde Tavira sediments,

thatcan be correlated tothoseof'Quelfes,yielded6.88±OA

Ma and 7.03 ±OA Ma; these ages fit well with the plankton icbiostratigraphy.

6)McmMoniz spongol ithscanbe ascribed tothe Upper Miocene, To rto nian,upper partofNI6orN17.

7) There arc im porta n t differences between the

biostratigraphicinformationand theS<'"/Sr" ageswhose error margins are quite broad.

Acknowledgements

Iam grateful to Prof. M.TellesAntunes forhelpful

review of this paper. Ithank Prof.Joao Pais foraid and

cooperationon fieldwork and SEM photography.

Antunes,M.T.;Bizon, G; Nascimento,A.&Pais,J.(1981)·Nouvellesdonneessur la datationdes depotsrniocenes de I'Algarve

(Portugal), et l'evolutiongeologiqueregionale.Ciencias da Terra(UNL),Lisboa, 6: 153· 168.

Antunes,M.T.;Odin, G& Pais,J.(1986) . AgesKIM de glauconiesdes environsde LuzdeTavira,Algarve.Ciencias da Terra (UNL).Lisboa, 8: 22·30.

Antunes, M.T.; Civis,J.; Dabrio,C. J.;Sierro,F.J.;Gonzalez-Delgado,J.A.; Flores,J.A.; Pais, J.&Valle, M.(1990)·EINeogenodel Algarve(Portugal)ydela cuenca del Guadalquivir(Espana).Actas dePaleontologla, UntversidaddeSalamanca,68: 65·73.

Antunes, M. T.;Elderfield,H.; Legoinha, P.,& Pais, J.(1997) . TheNeogene ofAlgarveillField Trip Guide •Excursion 1/The Guadalquivir Basin and Algarve(Spain. Portugal}, IICongress R.C.A.N.S.,Spain.

Ciim:io.1daTerra (UNL), 15

Berggren,W.A;Kent, D.

v.;

AUbry,M.-P.& Hard en bol,J.(1995)-Geochronology,time scalesandglobalstratigraphic correla

-tion.SEPM. SpecialPublication,54:386p.

Cachso,M.(199 5) - UtilizQfQO de nano!osseis ca/ctirios em biostratigrafia,paleoceanografia

e

paleoecologia. Aplicacoes ao Neogenico do Algarve(Portugal)e doMeditemmeo Ocidemal(ODP653)eIiproblematicadeCoccolithus pelagicus.Dissertacan

deDoutoramento ,UniversidadedcLisboa,356 p.

Civis,J.;Pais,L;Gonzalez-Delg ado,J.A & Legoinh a,P.(2000) -Slntesls paleontolcglcadelTortonten sesuperior deCacela

(Algarve,Portugal).I Congressolberico dePaleon/ologia/XVIJOn/ados de 10SodedadEspanola dePaleontolog ia -Livro de Resumos :IQ.I I.

Dollfus.G; Cotter,J.C.B.&Gomes,J.P.(1903-1904)-Mollusquestertiaires du Ponugal.PlanchesdeCepha.lopodes, GastCropodes er PelecypodeslaisseesparF.A.Pereira da Costa accompagneesd'uneexplicationsommaireetd'uneesquissegeologique.

Mem.Comm. Serv:Geol.Portugal. Lisboa:48 p.

Gonzalez-Delgado,J.A.&Civis,J.(2000).-Ciclici dadestacionalenperfilesdeIsotopesestablesde CyOdelbivalveMegacardi la jouannetidel Tortc niensesuperiorde Cace1a(Algarve,Portugal)y ArroyoTrujillo (Sevilla, Espana).CtmctasdaTerra(UNL) ,

Lisboa, 14: 297-302.

Legoinha,P.(2001 ) -Biastratigrafi ade Foraminiferos doMiocenicode Portugal(BaixoIejo eAlg arve) . Dissertacacdedoutorarncnto,

UniversidadeNova deLisboa,24 1p.,24est.

Manuppella,G(Coord.)(1992)-Carta Geologicada regilodoAlgarve,folhaecidental,na escalaI:100000.Servicos Geol6g icos dePortu gal.

Pais,1.;Lcgoinha,P.;Blderfield,H.;Sousa.L. & Estevens ,M.(2000) - TheNeogene of Algarve.Ciincias da Terra (UNL),

Lisboa,14:277-288.

Pereira da Costa, F.A.(1866 ) -Molluscos fcs seis/gasterepcd esdosdepo sitosterciarios de Portugal.Comissao Geologica de Portugal.10

Cademo,116 p.

Pereira da Costa, F.A.(1867 ) -Mclluscos fesseis/gasteropodes des depcs uos tercia riosde Portugal. Comissao Geologica de Portug al.ZO Cademo:117·252.

Ribeiro,A.;Antunes, M.T.;Ferreira,M.P.;Rocha,R.;Soares,A F.;Zbyszewski,G;MoitinhodeAlmeida, F.;Carvalho, D.&

Monteiro,1.H.(1979)-Introduction

a

la Geologie genm.le du Portugal.Serv. Geol.dePortugal.Lisbca;114p.

Romariz, C.;Correia,F.& Prates,S. (1979).Contributionsto the geologyof Algarve,Portugal.III- Unnouveaux [sic] faciesdu Miocene .Bol.Mus.Lab.Min.Geol.Fae.Ciene.Lisboa,16(I):265-271.

Sierro,F.J.(1985)-Thereplacementof theGloborotalia menordiigroupbytheGloborotalia miotumi dagroup:anaidtorecognizing

theTortonian-MessinianboundaryintheMediterra neanand theadjacentAtlantic.MarineMicropaleon/ology ,9: 525-535.

Sierro,F.J.;Flores,1.A.;Civis,J.;Ijonzalez-Delgado,J.A.& Frances,G(1993)·LateMiocenegloborotaliidevent-stratigra phy and biogeographyin the Ng -AtlanticandMediterranean.MarineMicropaleon tology,21:143-168.

Sierro,F.J.;Hilgen.F.J.;Krij gsman,W.&Flores,1.A.(2001)-The Abadcomposite(SE Spain):aMessinian referencesectionfor theMediterraneanand theAPTS.Paleogeography. Paleoclimalology,Paleoecology ,168:141-169.

Cibu:iasciaTara(UNL),IS

Pl

at e

1

Planktonic foraminifera.Scale. 100um,

Fig.1- Globorotalia miotumidaJenkins, 1960;Quelfessection.

Fig.2- Globorotaliagr.menardii(Parker.Jones& Brady, 1865 );Quelfessection.

Fig. 3,6- Neogloboquadrinahumerosa(Takayanagi& Saito, 1962) ; MemMoniz section.

Fig.4.5- Neogloboquadrina ocostaensis (Blow.1959);Mem Moniz section.

Fig.7, 8- Globorotalia(G)conomiozea Kennett, 1966;Quelfes section.

Ciencias daTerra (UNL),15