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Famennian transition beds in the Lijiaping section (Hunan, southern china)
0 Acadbmie Stratigraphie PalEtontologie
des sciences / Elsevier, / Strutigruphy / Pa/eonfology
Paris
Ostracods from the Frasnian/Famennian beds in the Lijiaping section (Hunan, China)
transition southern
Ostracodes des couches de passage du Frasnien au Famennien dans la coupe de L ijiaping (Hunan, Sud de la Chine) Jean-Georges CASIER, '* Francis LETHIERS~ and Hong-Fei Hou3 1 D@artement depalt?ontologie, Inslitut royal des sciences naturelles de Belgique, rue Vautiec 29, B-1000 Bruxelles, Belgique; ’ Laboratoare de micropalt?ontologie, dkpartement degtfoklgie sgdimentaire, Universit@Paris G, T25-15, 4E, case 104-4. place Jussieu, 75252 Paris cedex 05; ’ Institute of Geology, C.A.G.S.,Baiwanzbuang Road, Bei$ng 100037, People’s Republic of China
ABSTRACT Ostracods are highly abundant but poorly diversified in the Frasnian/Famennian (F/F) transition beds in the Lijiaping section of Hunan Province, southern China. Sixteen species have been recognized, and the fauna is distinctly dominated by Kloedenellacea, and by the genus Famenella Polenova, 1953. This assemblage represents probably the first evidence from Hunan, of an ostracod fauna recovering from the Late Devonian mass extinction event. Keywords:
Ostrocods,
Frasnian/Famennian
boundary,
h’unan,
China,
Extinction
Les Ostracodes sont tr& abondants, mais apparemmentpeu diversajiks dans les couches depassage du Frasnien au Famennien de la coupe de Lqiaping dans la Province du Hunan, en Chine. L’assemblage contient 16 esp@ceset il est largement dominkpar les Kloedenellacea etpar le genre Famenella Polenova, 1953. I1 pourrait marquer le d&but (du renouvellement faunique suivant la grande extinction du Dkvonien dans le Hunan, en Chine. Mats
cl&
: Ostracodes,
Limite
Frasnien/Famennien.
Hunan,
Chine,
Extinction
VERSION ABRI~G~E Introduction
La coupe de Lijiaping
Les travaux men& sur les Ostracodes, dans le cadre de l’ktude de la grande extinction du Dkvonien supi-rieur, ont permis de faire des progr& importants dans la connaissance de cette importante crise biologique. Or, jusqu’P present, aucune information ne concernait les Ostracodes en provenance du continent asiatique. Nous prksentons ici la dkcouverte d’une faune abondante d’ostracodes dans les couches de passage du Frasnien au Famennien de la coupe de Lijiaping, en Chine.
La coupe est sit&e par 26074' de latitude N et llO”80’ de longitude E, prPs de la gare de Lijiaping, dans la province du Hunan, 3 260 km au nord-est de Guilin et P 321km au sud-ouest de la ville de Qiyang (figure 1). Treize &hantillons trait& par la methode de l’acetolyse 2 chaud et tami& entre 100 et 1 650 pm, ont fourni environ 1 500 carapaces, valves et debris d’ostracodes, dont un peu plus de la moitii: sent identiliables. De la base au sommet, la succession lithologique, au niveau de
Xote pr&entCe par Jean Dercourt Note remix le 28 octobre 1996,accept&zapr&
revisionle 5 mai 1997
* E-mail: [email protected] C. R. Acad. Sci. Paris, Sciences 1997. 325,433.438
de lo terre
et des plan&es
/ Earth & Planetary
Sciences
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J.-G. Casier
et al
la hmite des &ages frasnien et famennien, est kt suivante dans la coupe de Lijiaping (figure 2) : - A) calcaires oncolitiques passant a des calcaires a fenestme (echantillon QSl); - B) 10 cm d’argiles jaunes (echantillon QS2); - C) 26 cm de schistes noirs I lentilles carbonatees (echantilIons QSS-QS5> - D) 30 cm de calcaires noduleux noirs (Pchantillons QS6QSl2);
- E) 40 cm de calcaires a oncolites (echantillons QS13); - F) 40 cm de calcaires coquilliers riches en pyrite: - C> marnes et calcaires bioclastiques.
Discussion Les Ostracodes sont extremement abondants dans les couches de transition de la coupe de Lijiaping, preuve dune sedimentation tres ralentie, mais 16 especes seulement sont identifiees (figure 3 et tableau). A l’exception de quatre carapaces appartenant probablement au genre <$herelliwa Jones et Holl, 1869, un genre de position systematique controversee (Casier et al., 1992). les especes appartiennent exclusivement aux Palaeocopida et aux Podocopida. La presence de ces derniers, qui sont detritivores, indique des conditions d’oxygenation satisfaisantes sur le fond marin,. par moment au moins (Lethiers et Wathley, 1994). Ainsi, sur base du rapport entre le nombre d’especes d’ostracodes filtreurs et celui des Ostracodes detritivores, nous pouvons estimer a environ 3,5 B 4,5 mL/L la teneur en oxygene dissous pour les niveaux C et D. L’assemblage est largement domine par les Kloedenellacea (54 % des specimens determinables) et par le genre Famenella Polenova, 1953 (39 o/o).
1. Introduction The Late Devonian mass extinction is one of the five greatest extinctions during the Phanerozoic, and probably 70% of all marine species were wiped out during this event around the Frasnian/Famennian boundary. For further informations regarding this extinction see Sandberg et al. (1988) and McGhee (I 996). The study of ostracods from southern Belgium, southern France and from Nevada (USA) has provided valuable information regarding this biological/geological crisis. The study of ostracods from these sections demonstrates or confirms the following. 1) The Frasnian/Famennian mass extinction was a catastrophic event, at least in lower latitudes. More than 70% of all marine ostracod species were wiped out in the western United States (Casier et al., 1996) and in southern France (Lethiers and Casier, 1996b). 2) The extinction took place in the later part of the linguiformis conodont zone (Lethiers and Casier, 1996b), and the Frasnian/Famennian boundary is placed at the start of the recovery from the extinction in the global stratotype section and point (GSSP) at Coumiac (Lethiers and Casier, 1996a). 3) The recovery of the ostracods in the formerly devastated marine environments began rapidly, owing to spe-
434
C. R. Acad.
Des assemblages domines par un nombre rgduit d‘especes cardcterisent des milieux semi-restreints &ins I‘ecotype de l’Eife1 de Becker (in: Bandel et Becker, 1975). De tels assemblages sont presents dans le Famennien basal de plusieurs coupes beiges (Sinsin. Ilony, Lambermont), ou les valves des Ostracodes sont parfois imbriquees. at testant la faible profondeur du fond marin (Casier et Devleeschounrer, 1995). Un te1 assemblage se retrouve aussi dans le stratotype historique de la limite des &ages Frasnien et Famennien. 3 Senzeille, oil l’analyse sedimentologique indique un milieu relativement plus profond. Cela permet de stpposer que la recolonisation du fond marin commence avec des especes preset-&es dans des milieux peu profonds. apres l’cxtinction du Devonien superieur. Une recolonisation de ce type cst aussi envisagee pour le limitotype des etages frasnien et famennien a Coumiac, en France (Lethiers et Casier. 1996a) et pour la coupe de Devils Gate, au Nevada (Casier et Lethiers. sous presse). L’abondance des Kloedenellacea et des I;ameuella Polenova, 1953, darts la coupe de Lijiaping, indique que la recolonisation dans le Hunan pourrait egalement avoir eu lieu a partir d’especes refugiees en milieu peu profond. Si cette hypothtse se verifiait, les Ostracodes presents dans les niveaux C et D marqueraient le debut du renouvellement faunique. suivant la grande extinction du Devonien superieur dans cette region du monde. De ce fait? la limite des &ages frasnien et famennien se situerait entre les niveaux B et C, soit directement au-dessus d’un niveau argileux interpret6 comme une bentonite ou comme resultant dune intense alteration subaerienne, mais pour lequel d’autres interpretations sont Pgalement plausiblcs (HOLI et al., 1996).
ties sheltered in very shallow-water marine environments (Lethiers and Casier, 1996a; Casier and Lethiers, 1997). 4) The extinction is, in part, linked to the influx of oxygendepleted water on the shelf during the latest Frasnian (Casier, 1987; Lethiers and Casier, 1995). 5) The extinction is also linked with a drastic fall in sea level (Casier and Devleeschouwer, 1995), and with a climatic change (Lethiers and Raymond, 1991). The goal of this first paper on the ostracods involved in the Late Devonian mass extinction in China is to present the species occurring in the Frasnian/Famennian transition beds in the Lijiaping section of the Hunal? Province of southern China.
II. The Frasnian/Famennian boundary in southern China and the Lijiaping section The Frasnian/Famennian boundary was recently investigated in southern China by Hou et al. (1988, 1992), Ji (I990), Wang et al. (I 991) and Zheng et al. (1993) in basinal-, slope-, platformand nearshore-marine sediments. These studies demonstrated that black shales and nodular limestones occur close to the Frasnian/Famennian boundary in several Chinese sections. Moreover, at Xiang-
SCI. Paris, Sciences
de lo terre et des plan&es
/ Earth
& Planetary Sciences 1907. 325,433.438
Ostracods
0
0
?
0
0
0
0
0
0
0
t
0
the
FrasnianiFamenntan
.JIANGNAh
0
l 0 0 0
Carte
du Sud-Est
tian, weak
Cuangxi, a strong negative Ir anomaly coincide with
boundary
Devonian
facies
de /a Chine
(Wang
montrant
et al.,
In central Hunan, argillaceous bioclastic between the Frasnian
distribution
in south-eastern
/es ditikents
facitis
China, du Dborrien
excursion of 6°C the Frasnian/Famennian
’
section
’ . 0
0
0
0 ..~.~~~ .... c 0
,
0
0
-4
. .
e
4
0
-t
1. Upper
Lijiaping
0
0
Figure
’
I;HENGYANG:::: ................ ..... . .................
l
0
in the
...... .iHANWHA:::::::::::a’ .............................. ............................. ...................................................... ....................... ...................... ...................... .. .. ................
CONTINEP 1
beds
::~~
0
0
transition
’ CONTINENT 1
0
0
YANGZI 0
l
0
l 0
0
0
from
and
and
geographic
sup&ieur
tral
1991).
nian Xikwangshan limestone (Hou et al., 1988). These shales show a flat, laminated stratification and were obviously deposited in quiet water below wave base. The bioclastic limestones contain brachiopods, crinoids, bivalves, bryozoans, corals and stromatoporoids (Hou et al.,
of the
et localisation
a
shales intercalated with thin-bedded, and nodular limestones are present Qilijiang limestone and the Famen-
position
-.-
100
Lijiaping
de la coupe
section
(From
de Lijiaping
(d’aprk.5
By comparison with the Laojiangchong Hunan about 150 km northwest
Frasnian/Famennian bed D and E (Hou
boundary et al., 1996).
Hou
was
Hou
ol:
inferred
200K1
et al.,
1996).
eta/.,
1996).
section of cenLijiaping, the to be between
III. Ostracods from the Frasnian/Famennian transition beds in the Lijiaping section (figure 3 and table)
1988).
1.
In the Lijiaping section (26”74’N; 110’80’E) platform sediments are exposed near the Lijiaping rail,way station 260 km NE of Guilin and 32 km SW of Qiyang City, and in
Thirteen small samples have been collectecl by the third author from units A to E, and about 1 500 carapaces, valves and fragments of ostracods have been extracted by
southern Hunan Province the lithological succession A) Oncolitic limestones limestones with a distinct
the “hot acetolyse method”, and by crushing and sieving the samples between 100 and 1 650 Pm. Ostracods are very rare in the top of level A (sample QSI ), absent in level
(figure 1). From bottom to top, (figure 2) is as follows: that grade upward into fenestral algal lamination, both indicative
Sampling
of a shallowing upwards sequence (sample QSl); B) 10 cm of yellow clay (sample QS2). This unit is generally interpreted as a bentonitic layer, but other interpretations could be considered as alternatives, as outlined later;
B (sample QSZ), but abundant in levels C and D, except for samples QS4 and QSIO, which are unfossiliferous, and sample QS12 in which ostracods are scarce. Qstracods are also rare in the base of level E (sample QSI 3). Altogether, more than 750 ostracod specimens coulcl be identified.
C) 26 cm of black eous lenses;
2.
D)
30
cm
of
black
shale
(samples
nodular
QS3-QS5) limestone
with
calcar-
(samples
QS6Order
QSl2); E) 40 cm
Systematic
of limestone
with
oncolites
F) 40 cm of coquina limestone rich G) marls and bioclastic limestones. C R. Acad. Sci 1997 325,433.438
Parls,
Sciences
de
la terre
(sample
list
Palaeocopida
Superfamily
QSl3);
Family
in pyrite;
Beyrichiidae
plan&es
/ Earth
& Planetary
Sciences
species
identified
Henningsmoen,
Beyrichiacea
Ochescapha et des
of ostracod
1953
Matthew, Matthew,
cf. tichomirovi
1886
1886 (Tschigova,
1963)
435
J.-G.
Casier
et al.
m
F E
Figure 2. Lifholagical Frasnian/Famenniln IA, B, C...), and far
s~puenm bwundary. the position
of the Lijiaping See text far the of the ostracad
,p
across the of beds analyzed.
Colonne lithologique de la coupe de Lijiaping au niveau de /a limite Frasnien/Famennien. Voir le textepour /a description des niveaux (A, B, C...) et pour /a position des &hanti//ons r&o/& pour /‘etude des ostracodes.
Ochescapha sp. A Superfamily Kloedenelfacea Ufrrch and Bass(er, 1908 Family Knoxitldae Egorov, 1950 Knoxiella cf. domanica Rozhdestvenskaja, 1972 Knoxiella SP. A, aff. compressa Rozhdestvenskaja, 1972 Family Serenididae Rozhdestvenskaja, 1972 Serenida dushanensis (SHI, 1964) Tchizhovaella n. sp A, aff. regina L&rers, 7978 Family Indivlsrldae Egorov, 1954 lndivisia aff baschkirica Rozhdestvenskaja and Tschigova, 1972 Order Metacopida Sylvester-Bradley, 1961 Superfamily Healdiacea Harlton, 1933 Family Healdildae Harlton, 1933 Cytherell,na? sp A tirder fodocapida Muiier, 7 894 Superfamily Balrdiacea Sars, 1888 Family Acratiidae Grtindel, 1962 Acratia sp. A Family Acratiidae Grtindel, 1962? Famenella ti. sp. ,4, aff. perspiqua Rozhdestvenskaja, 1972 Famenella cf bisangulata Lethiers, 1981 Family
Badridae
Sars,
1888
Bairdia flJlrw&rnr Egorov, 1953 Bairdia cf. ischimensis Egorov, 195 3 Bairdia sp. B, aff. galinae Egorov, 1953 Bairdia sp. C, aff. dorsoconstricta Blbrnenstengel, Family Bairdiocyprididae Shaver, 1961 Orthocypns cf. exemplaris Rozhdeslvenskaja,
436
figuR3. Usfmc6d Species from th~F~dsRian/idmc~~i=~ t~an&'m~ bpds in the Lijiaping scc(i~n (Hunan, China). IRQNB qq = collecGon number of the Depatiment of Paleontology, Belgian Royal institute of Natural scicnqes. A, C, E, C, I, K, M, N, P-T = lateral views; 8, D, F, H, I, L, 0 2 dorsal views. b:i “::%a:
Ostracodes des couches de passage Frasnien/Farwnnien dans /a cvupe de Lijiaping (Hunan. Chine). IRScNB N” = rwn-&o de collecIron du Departement de Palt%nta/ogie de /‘/nstitut rryJ/ de5 Sciences ~WW@FS de Be.!gjQ~~ A, C, E, G, $. K, M, N, P T = wp~ Iai⩽ 8, (7. 5 tf, J, L, 0 = i/o@5 dord?S. A: Knoxiella cf. domanlca Rozhdestvenskaja, 1422, Qx~; IRScNB N” b3135; (x 30). B: Idcm; QSS; IRSCNB N” b-1136; (X 25). C: Knoxiella sp. A, at%. compressa Rozhdestvenskaja, 1972; QSJ 7; IRScNB N” b3737; (X 30). D: Idem; QS71; /RScNB N” b3138; (x 311, E: Serenida dushanensis (Sh;, 1964); QSS; /RScNB N” b3139; (x 25). F: Idem; QS8; lRScN6 N’b3740; (x 25). G:Tchizhov+lla n. sp. A, aff. regina Lethiers, 1978; QSB. [RScNB No b3141; (K 4,‘) H: I&m; QSS; IUScNB N” b3142; h 421 I Indivisia aff. baschklrlca i?v&&stvenskala & i5cb&nva, 1872; (756, IScNE N” b3 743; @ ~51 f- Idem; QSB; IRScNB N” b3 144, (x 26). K: Ochescaphd C/ rl
3. Characters
1969 19721
of the assemblage
Despite that ostracods are individually extremely abundant in the F/F trahsition beds of the Lijiaping section indicating a very slow rate of sedimenration, only 16
Ostracods
Tableau.
Distribution
R@partition
Beds
des
of ostracods
Ostracodes
au niveau
(see text)
Sample
regina
nalivkini
Knoxiella
sp. A, afi
lndivisia
aii. baschkirica
?Orthocypris
compressa
cf. exemplaris indet.
Famenella
cf. bisangulata
Ochescapha
sp. A
Palaeocopida
indet.
Ochescapha Serenida
. . . .
perspiqua
n. sp. A, a#
dans
in the la coupe
QS5
QS6
. . . . . . . ? . . . . .
. . . . . . . . . . . .
dushanensis sp. C, aK dorsoconstricta
Bairdia
sp. A, aff
Bairdia
sp. B, aff. galinae
Cytherellina
L&aping
beds
in the
ischimensis
! sp. A
Lijiaping
section
section.
de Lijiaping.
E
QS7
QS8
QS9
. . . . . . .
. . . . . . .
.
. . .
. .
.
. . . . . .
. . .
.
QSll
. .
. . .
.
. .
QSl2
QS73
. .
. . . . .
. .
sp. A
species could be recognized. With the exception of four carapaces belonging questionably to Cytherellina Jones and Hall, 1969, a genus of controversial systematic position (Casier et al., 1992), the ostracod species identified belong exclusively to the palaeocopids and the podocopids. The species, listed in terms of decreasing abundance, are: Fameneila n. sp. A, aff. perspiqua Rozhdestvenskaja, 1972; lndivisia aff. baschkirica Rozhdestvenskaja and Tschigova, 1972; and Tchizhovaella n. sp. A, aff. regina Lethiers, 1978. Knoxie//a cf. domanica Rozhdestvenskaja, 1972; Famenella cf. bisangulata Lethiers, 1981; and Serenida dushanensis (Shi, 1964) are more rare. Ochescapha cf. tichomirovi (Tschigova, 1963); Ochescapha sp. A; Knoxiella sp. A aff. compressa Rozhdestvenskaja, 1972; Orthocypris cf. exemplaris Rozhdestvenskaja, 19722; four species of Bairdia MC Coy, 1944; and Acratia sp. A are extremely rare.
IV. Interpretation The ostracod assemblage occurring in the Frasnian/Famennian boundary beds of the Lijiaping section is distinctly dominated by ostracods belonging to the Kloedenellacea (54% of specimens), and by the genus Famenella Polenova, 1953 (39%). Affinities seem to be greater with species previously described from Famennian rather than from Frasnian deposits, and the assemblage is C. R. Acad. Sci. 1997. 325,433-438
transition
D
cf. tichomirovi
Bairdia
Frasnian/Famennian
C
.
afi
the
boundary
Frasnien/Famennien
QS3
cf. domanica
Tchizhovaella
Baird/a
de la limite
indet.
Famenella n. sp. A, Bairdia
Frasnian/Famennian
Q-51
indet
Kloedenellacea Knoxiella
the
A
designation
Podocopida
Acratia
across
from
Paris,
Sciences
de
la terre
et des
plan&tes
/ Earth
not characteristic of oxygen-depleted water conditions. In fact, the occurrence of several species of podocopids, which are deposit feeders, indicates well-oxygenated conditions on the sea floor during at least brief intervals (Lethiers and Whatley, 1994). The relative proportion of filter-feeding ostracod species in comparis’on with depositfeeding ones, therefore, suggests an oxy:gen level about 3.5-4.5 mL/L O2 for beds C and D. Very abundant individually, but poorly diversified assemblages indicate semi-restricted conditions in the Eifelian ecotype of Becker (Bandel and Becker, 1975). Such “impoverished” assemblages occur in the lowermost Famennian beds in several Belgian sections at the southern border of the Dinant Basin, the type area for the Frasnian and Famennian stages. At Sinsin and Lambermont, nested ostracod valves are common, suggesting very shallow-water conditions (Casier and Devleeschouwer, 1995). In the former stratotype section for the Frasnian/Famennian boundary at Senzeille, however, such apparently shallowwater ostracod assemblages occur in sediments indicative of deeper-water settings. Consequently, it is concluded that the recovery of the ostracod fauna after the mass extinction event began in the southern border of the Dinant Basin, with species sheltered in very shallow-water environments and which were not affected by the irlflux of oxygendepleted water on the shelf. Moreover, this process of recovery has been also suggested for ostracods in the new & Plunetory
Sciences
J.-G.
Casier et al.
Frasnian/Famennian boundary stratotype section and point (CSSP) at Coumiac in southern France (Lethiers and Casier, 1996a) and in the famous Devils Gate Pass section in Nevada of the western United States (Casier and Lethiers, 1997). In the upper quarry at Coumiac, the Frasnian/Famennian boundary has been placed directly above a 12 cm thick grey, coarse-grained dolomitic limestone (Klapper et al., 1994). This bed is believed to be equivalent to the German Upper Kellwasser Limestone (Becker et al., 1989), a limestone deposited under hypoxic conditions in the Harz Mountains of Germany. These oxygen-depleted conditions are considered to be at least partially responsible for the mass extinction and, at Coumiac, more than 75% of the ostracod fauna disappeared close to the base or
Acknowledgements: We sincerely thank C. Sandberg of the United University of Saskatchewan, Saskatoon, for reviewing the manuscript.
within this boundary unit. The recovery tion began immediately above.
from the extinc-
By comparison, we conclude that the ostracod fauna occurring in beds C and D in the Lijiaping section represents the first indication that the ostracod fauna had recovered from the Late Devonian extinction in Hunan. Consequently, the Frasnian/Famennian boundary would be better placed between unit B and C in the Lijiaping section, rather than between units D and E as originally determined. In fact, the chemical composition of the yellow-coloured clay that constitutes the B unit allows for several interpretations such as e.g. a bentonite layer, or a layer that underwent intense subaerial weathering (Hou et al., 1996) indicating a major unconformity and so on.
States
Geological
Survey,
Denver
and
W.K. Braun
of the
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Lethiers F. and Casier J.-G. 1996a. Les Ostracodes survivants I’&&nement F/F duns le limitotype de Coumiac (Montagne Noire. France). Ann. Sot. gkol. Belgique, 117. 1, 137-153
cj
Lethiers F. and Casier J.-G. 1996b. Les Ostracodes qui disparaissent avec I’&&ement Frasnien/Famennien au limitotype de Coumiac (Montagne Noire. France), Bull. Insf. ray. Sci. nat. Belgique, Sci. de /a Terre, 66, 73-91 Lethiers F. and Raymond D. 1991. Les crises du D&onien superieur par I’Qtude des faunes d’ostracodes duns leur cadre pal6og6ographique. Palaeogeogr., falaeoclimat., Polaeoecol. 88, 133-146 Lethiers F and Whatley R. 1994. The use of Ostracoda to reconstruct the oxygen levels of Late Paleozotc ocean;, Marine Micropa/, 24,57-69 McGhee G. 1996. The Late Devonian Mass Extinction. The FrasnianiFamennian crisis, In: Bottjer and Banbach (eds), Critical Moments in Paleobiology and Earth History Series, Columbia. University Press, 303 p, Sandberg C., Ziegler W.. Dreesen R. and Butler J, 1988. Late Frasnian mass extinction: Conodont event stratigraphy. global changes, and possible cause, Cour. Forschungsinst. Senckenberg, 102,267.297 Wang seizer event ology,
K.. Orth C.. Moses A.. Chatterton B., Hou H.-F. and GeldH. 1991, Geochemicai evidence for a catastrophic biotic at the Frasnian/Famennian boundary in south China, Ge19,776.779
Wang K., Geldsetzer Carbon and sulfur Famennian extinction 2, 187-191
H., Goodfellow W. and Krause H. 1996. isotope anomalies across the Frasnianboundary, Alberta, Canaoa. Geology, 24.
Zheng Y, Hou H.-F. and Ye L.-F 1993. Carbon and oxygen isotope event markers near the Frasnian-Famennian boundary, Luoxiu section, South China, Palaeogeogr., Palaeoclimat., Palaeoecol.. 104.97-104
SCI. Paris, Sciences
de
la terre et des plan&es
/ Earth
& Planetary Sciences 1997. 325,433.438
des sciences / Elsevier, / Strutigruphy / Pa/eonfology
Paris
Ostracods from the Frasnian/Famennian beds in the Lijiaping section (Hunan, China)
transition southern
Ostracodes des couches de passage du Frasnien au Famennien dans la coupe de L ijiaping (Hunan, Sud de la Chine) Jean-Georges CASIER, '* Francis LETHIERS~ and Hong-Fei Hou3 1 D@artement depalt?ontologie, Inslitut royal des sciences naturelles de Belgique, rue Vautiec 29, B-1000 Bruxelles, Belgique; ’ Laboratoare de micropalt?ontologie, dkpartement degtfoklgie sgdimentaire, Universit@Paris G, T25-15, 4E, case 104-4. place Jussieu, 75252 Paris cedex 05; ’ Institute of Geology, C.A.G.S.,Baiwanzbuang Road, Bei$ng 100037, People’s Republic of China
ABSTRACT Ostracods are highly abundant but poorly diversified in the Frasnian/Famennian (F/F) transition beds in the Lijiaping section of Hunan Province, southern China. Sixteen species have been recognized, and the fauna is distinctly dominated by Kloedenellacea, and by the genus Famenella Polenova, 1953. This assemblage represents probably the first evidence from Hunan, of an ostracod fauna recovering from the Late Devonian mass extinction event. Keywords:
Ostrocods,
Frasnian/Famennian
boundary,
h’unan,
China,
Extinction
Les Ostracodes sont tr& abondants, mais apparemmentpeu diversajiks dans les couches depassage du Frasnien au Famennien de la coupe de Lqiaping dans la Province du Hunan, en Chine. L’assemblage contient 16 esp@ceset il est largement dominkpar les Kloedenellacea etpar le genre Famenella Polenova, 1953. I1 pourrait marquer le d&but (du renouvellement faunique suivant la grande extinction du Dkvonien dans le Hunan, en Chine. Mats
cl&
: Ostracodes,
Limite
Frasnien/Famennien.
Hunan,
Chine,
Extinction
VERSION ABRI~G~E Introduction
La coupe de Lijiaping
Les travaux men& sur les Ostracodes, dans le cadre de l’ktude de la grande extinction du Dkvonien supi-rieur, ont permis de faire des progr& importants dans la connaissance de cette importante crise biologique. Or, jusqu’P present, aucune information ne concernait les Ostracodes en provenance du continent asiatique. Nous prksentons ici la dkcouverte d’une faune abondante d’ostracodes dans les couches de passage du Frasnien au Famennien de la coupe de Lijiaping, en Chine.
La coupe est sit&e par 26074' de latitude N et llO”80’ de longitude E, prPs de la gare de Lijiaping, dans la province du Hunan, 3 260 km au nord-est de Guilin et P 321km au sud-ouest de la ville de Qiyang (figure 1). Treize &hantillons trait& par la methode de l’acetolyse 2 chaud et tami& entre 100 et 1 650 pm, ont fourni environ 1 500 carapaces, valves et debris d’ostracodes, dont un peu plus de la moitii: sent identiliables. De la base au sommet, la succession lithologique, au niveau de
Xote pr&entCe par Jean Dercourt Note remix le 28 octobre 1996,accept&zapr&
revisionle 5 mai 1997
* E-mail: [email protected] C. R. Acad. Sci. Paris, Sciences 1997. 325,433.438
de lo terre
et des plan&es
/ Earth & Planetary
Sciences
433
J.-G. Casier
et al
la hmite des &ages frasnien et famennien, est kt suivante dans la coupe de Lijiaping (figure 2) : - A) calcaires oncolitiques passant a des calcaires a fenestme (echantillon QSl); - B) 10 cm d’argiles jaunes (echantillon QS2); - C) 26 cm de schistes noirs I lentilles carbonatees (echantilIons QSS-QS5> - D) 30 cm de calcaires noduleux noirs (Pchantillons QS6QSl2);
- E) 40 cm de calcaires a oncolites (echantillons QS13); - F) 40 cm de calcaires coquilliers riches en pyrite: - C> marnes et calcaires bioclastiques.
Discussion Les Ostracodes sont extremement abondants dans les couches de transition de la coupe de Lijiaping, preuve dune sedimentation tres ralentie, mais 16 especes seulement sont identifiees (figure 3 et tableau). A l’exception de quatre carapaces appartenant probablement au genre <$herelliwa Jones et Holl, 1869, un genre de position systematique controversee (Casier et al., 1992). les especes appartiennent exclusivement aux Palaeocopida et aux Podocopida. La presence de ces derniers, qui sont detritivores, indique des conditions d’oxygenation satisfaisantes sur le fond marin,. par moment au moins (Lethiers et Wathley, 1994). Ainsi, sur base du rapport entre le nombre d’especes d’ostracodes filtreurs et celui des Ostracodes detritivores, nous pouvons estimer a environ 3,5 B 4,5 mL/L la teneur en oxygene dissous pour les niveaux C et D. L’assemblage est largement domine par les Kloedenellacea (54 % des specimens determinables) et par le genre Famenella Polenova, 1953 (39 o/o).
1. Introduction The Late Devonian mass extinction is one of the five greatest extinctions during the Phanerozoic, and probably 70% of all marine species were wiped out during this event around the Frasnian/Famennian boundary. For further informations regarding this extinction see Sandberg et al. (1988) and McGhee (I 996). The study of ostracods from southern Belgium, southern France and from Nevada (USA) has provided valuable information regarding this biological/geological crisis. The study of ostracods from these sections demonstrates or confirms the following. 1) The Frasnian/Famennian mass extinction was a catastrophic event, at least in lower latitudes. More than 70% of all marine ostracod species were wiped out in the western United States (Casier et al., 1996) and in southern France (Lethiers and Casier, 1996b). 2) The extinction took place in the later part of the linguiformis conodont zone (Lethiers and Casier, 1996b), and the Frasnian/Famennian boundary is placed at the start of the recovery from the extinction in the global stratotype section and point (GSSP) at Coumiac (Lethiers and Casier, 1996a). 3) The recovery of the ostracods in the formerly devastated marine environments began rapidly, owing to spe-
434
C. R. Acad.
Des assemblages domines par un nombre rgduit d‘especes cardcterisent des milieux semi-restreints &ins I‘ecotype de l’Eife1 de Becker (in: Bandel et Becker, 1975). De tels assemblages sont presents dans le Famennien basal de plusieurs coupes beiges (Sinsin. Ilony, Lambermont), ou les valves des Ostracodes sont parfois imbriquees. at testant la faible profondeur du fond marin (Casier et Devleeschounrer, 1995). Un te1 assemblage se retrouve aussi dans le stratotype historique de la limite des &ages Frasnien et Famennien. 3 Senzeille, oil l’analyse sedimentologique indique un milieu relativement plus profond. Cela permet de stpposer que la recolonisation du fond marin commence avec des especes preset-&es dans des milieux peu profonds. apres l’cxtinction du Devonien superieur. Une recolonisation de ce type cst aussi envisagee pour le limitotype des etages frasnien et famennien a Coumiac, en France (Lethiers et Casier. 1996a) et pour la coupe de Devils Gate, au Nevada (Casier et Lethiers. sous presse). L’abondance des Kloedenellacea et des I;ameuella Polenova, 1953, darts la coupe de Lijiaping, indique que la recolonisation dans le Hunan pourrait egalement avoir eu lieu a partir d’especes refugiees en milieu peu profond. Si cette hypothtse se verifiait, les Ostracodes presents dans les niveaux C et D marqueraient le debut du renouvellement faunique. suivant la grande extinction du Devonien superieur dans cette region du monde. De ce fait? la limite des &ages frasnien et famennien se situerait entre les niveaux B et C, soit directement au-dessus d’un niveau argileux interpret6 comme une bentonite ou comme resultant dune intense alteration subaerienne, mais pour lequel d’autres interpretations sont Pgalement plausiblcs (HOLI et al., 1996).
ties sheltered in very shallow-water marine environments (Lethiers and Casier, 1996a; Casier and Lethiers, 1997). 4) The extinction is, in part, linked to the influx of oxygendepleted water on the shelf during the latest Frasnian (Casier, 1987; Lethiers and Casier, 1995). 5) The extinction is also linked with a drastic fall in sea level (Casier and Devleeschouwer, 1995), and with a climatic change (Lethiers and Raymond, 1991). The goal of this first paper on the ostracods involved in the Late Devonian mass extinction in China is to present the species occurring in the Frasnian/Famennian transition beds in the Lijiaping section of the Hunal? Province of southern China.
II. The Frasnian/Famennian boundary in southern China and the Lijiaping section The Frasnian/Famennian boundary was recently investigated in southern China by Hou et al. (1988, 1992), Ji (I990), Wang et al. (I 991) and Zheng et al. (1993) in basinal-, slope-, platformand nearshore-marine sediments. These studies demonstrated that black shales and nodular limestones occur close to the Frasnian/Famennian boundary in several Chinese sections. Moreover, at Xiang-
SCI. Paris, Sciences
de lo terre et des plan&es
/ Earth
& Planetary Sciences 1907. 325,433.438
Ostracods
0
0
?
0
0
0
0
0
0
0
t
0
the
FrasnianiFamenntan
.JIANGNAh
0
l 0 0 0
Carte
du Sud-Est
tian, weak
Cuangxi, a strong negative Ir anomaly coincide with
boundary
Devonian
facies
de /a Chine
(Wang
montrant
et al.,
In central Hunan, argillaceous bioclastic between the Frasnian
distribution
in south-eastern
/es ditikents
facitis
China, du Dborrien
excursion of 6°C the Frasnian/Famennian
’
section
’ . 0
0
0
0 ..~.~~~ .... c 0
,
0
0
-4
. .
e
4
0
-t
1. Upper
Lijiaping
0
0
Figure
’
I;HENGYANG:::: ................ ..... . .................
l
0
in the
...... .iHANWHA:::::::::::a’ .............................. ............................. ...................................................... ....................... ...................... ...................... .. .. ................
CONTINEP 1
beds
::~~
0
0
transition
’ CONTINENT 1
0
0
YANGZI 0
l
0
l 0
0
0
from
and
and
geographic
sup&ieur
tral
1991).
nian Xikwangshan limestone (Hou et al., 1988). These shales show a flat, laminated stratification and were obviously deposited in quiet water below wave base. The bioclastic limestones contain brachiopods, crinoids, bivalves, bryozoans, corals and stromatoporoids (Hou et al.,
of the
et localisation
a
shales intercalated with thin-bedded, and nodular limestones are present Qilijiang limestone and the Famen-
position
-.-
100
Lijiaping
de la coupe
section
(From
de Lijiaping
(d’aprk.5
By comparison with the Laojiangchong Hunan about 150 km northwest
Frasnian/Famennian bed D and E (Hou
boundary et al., 1996).
Hou
was
Hou
ol:
inferred
200K1
et al.,
1996).
eta/.,
1996).
section of cenLijiaping, the to be between
III. Ostracods from the Frasnian/Famennian transition beds in the Lijiaping section (figure 3 and table)
1988).
1.
In the Lijiaping section (26”74’N; 110’80’E) platform sediments are exposed near the Lijiaping rail,way station 260 km NE of Guilin and 32 km SW of Qiyang City, and in
Thirteen small samples have been collectecl by the third author from units A to E, and about 1 500 carapaces, valves and fragments of ostracods have been extracted by
southern Hunan Province the lithological succession A) Oncolitic limestones limestones with a distinct
the “hot acetolyse method”, and by crushing and sieving the samples between 100 and 1 650 Pm. Ostracods are very rare in the top of level A (sample QSI ), absent in level
(figure 1). From bottom to top, (figure 2) is as follows: that grade upward into fenestral algal lamination, both indicative
Sampling
of a shallowing upwards sequence (sample QSl); B) 10 cm of yellow clay (sample QS2). This unit is generally interpreted as a bentonitic layer, but other interpretations could be considered as alternatives, as outlined later;
B (sample QSZ), but abundant in levels C and D, except for samples QS4 and QSIO, which are unfossiliferous, and sample QS12 in which ostracods are scarce. Qstracods are also rare in the base of level E (sample QSI 3). Altogether, more than 750 ostracod specimens coulcl be identified.
C) 26 cm of black eous lenses;
2.
D)
30
cm
of
black
shale
(samples
nodular
QS3-QS5) limestone
with
calcar-
(samples
QS6Order
QSl2); E) 40 cm
Systematic
of limestone
with
oncolites
F) 40 cm of coquina limestone rich G) marls and bioclastic limestones. C R. Acad. Sci 1997 325,433.438
Parls,
Sciences
de
la terre
(sample
list
Palaeocopida
Superfamily
QSl3);
Family
in pyrite;
Beyrichiidae
plan&es
/ Earth
& Planetary
Sciences
species
identified
Henningsmoen,
Beyrichiacea
Ochescapha et des
of ostracod
1953
Matthew, Matthew,
cf. tichomirovi
1886
1886 (Tschigova,
1963)
435
J.-G.
Casier
et al.
m
F E
Figure 2. Lifholagical Frasnian/Famenniln IA, B, C...), and far
s~puenm bwundary. the position
of the Lijiaping See text far the of the ostracad
,p
across the of beds analyzed.
Colonne lithologique de la coupe de Lijiaping au niveau de /a limite Frasnien/Famennien. Voir le textepour /a description des niveaux (A, B, C...) et pour /a position des &hanti//ons r&o/& pour /‘etude des ostracodes.
Ochescapha sp. A Superfamily Kloedenelfacea Ufrrch and Bass(er, 1908 Family Knoxitldae Egorov, 1950 Knoxiella cf. domanica Rozhdestvenskaja, 1972 Knoxiella SP. A, aff. compressa Rozhdestvenskaja, 1972 Family Serenididae Rozhdestvenskaja, 1972 Serenida dushanensis (SHI, 1964) Tchizhovaella n. sp A, aff. regina L&rers, 7978 Family Indivlsrldae Egorov, 1954 lndivisia aff baschkirica Rozhdestvenskaja and Tschigova, 1972 Order Metacopida Sylvester-Bradley, 1961 Superfamily Healdiacea Harlton, 1933 Family Healdildae Harlton, 1933 Cytherell,na? sp A tirder fodocapida Muiier, 7 894 Superfamily Balrdiacea Sars, 1888 Family Acratiidae Grtindel, 1962 Acratia sp. A Family Acratiidae Grtindel, 1962? Famenella ti. sp. ,4, aff. perspiqua Rozhdestvenskaja, 1972 Famenella cf bisangulata Lethiers, 1981 Family
Badridae
Sars,
1888
Bairdia flJlrw&rnr Egorov, 1953 Bairdia cf. ischimensis Egorov, 195 3 Bairdia sp. B, aff. galinae Egorov, 1953 Bairdia sp. C, aff. dorsoconstricta Blbrnenstengel, Family Bairdiocyprididae Shaver, 1961 Orthocypns cf. exemplaris Rozhdeslvenskaja,
436
figuR3. Usfmc6d Species from th~F~dsRian/idmc~~i=~ t~an&'m~ bpds in the Lijiaping scc(i~n (Hunan, China). IRQNB qq = collecGon number of the Depatiment of Paleontology, Belgian Royal institute of Natural scicnqes. A, C, E, C, I, K, M, N, P-T = lateral views; 8, D, F, H, I, L, 0 2 dorsal views. b:i “::%a:
Ostracodes des couches de passage Frasnien/Farwnnien dans /a cvupe de Lijiaping (Hunan. Chine). IRScNB N” = rwn-&o de collecIron du Departement de Palt%nta/ogie de /‘/nstitut rryJ/ de5 Sciences ~WW@FS de Be.!gjQ~~ A, C, E, G, $. K, M, N, P T = wp~ Iai⩽ 8, (7. 5 tf, J, L, 0 = i/o@5 dord?S. A: Knoxiella cf. domanlca Rozhdestvenskaja, 1422, Qx~; IRScNB N” b3135; (x 30). B: Idcm; QSS; IRSCNB N” b-1136; (X 25). C: Knoxiella sp. A, at%. compressa Rozhdestvenskaja, 1972; QSJ 7; IRScNB N” b3737; (X 30). D: Idem; QS71; /RScNB N” b3138; (x 311, E: Serenida dushanensis (Sh;, 1964); QSS; /RScNB N” b3139; (x 25). F: Idem; QS8; lRScN6 N’b3740; (x 25). G:Tchizhov+lla n. sp. A, aff. regina Lethiers, 1978; QSB. [RScNB No b3141; (K 4,‘) H: I&m; QSS; IUScNB N” b3142; h 421 I Indivisia aff. baschklrlca i?v&&stvenskala & i5cb&nva, 1872; (756, IScNE N” b3 743; @ ~51 f- Idem; QSB; IRScNB N” b3 144, (x 26). K: Ochescaphd C/ rl
3. Characters
1969 19721
of the assemblage
Despite that ostracods are individually extremely abundant in the F/F trahsition beds of the Lijiaping section indicating a very slow rate of sedimenration, only 16
Ostracods
Tableau.
Distribution
R@partition
Beds
des
of ostracods
Ostracodes
au niveau
(see text)
Sample
regina
nalivkini
Knoxiella
sp. A, afi
lndivisia
aii. baschkirica
?Orthocypris
compressa
cf. exemplaris indet.
Famenella
cf. bisangulata
Ochescapha
sp. A
Palaeocopida
indet.
Ochescapha Serenida
. . . .
perspiqua
n. sp. A, a#
dans
in the la coupe
QS5
QS6
. . . . . . . ? . . . . .
. . . . . . . . . . . .
dushanensis sp. C, aK dorsoconstricta
Bairdia
sp. A, aff
Bairdia
sp. B, aff. galinae
Cytherellina
L&aping
beds
in the
ischimensis
! sp. A
Lijiaping
section
section.
de Lijiaping.
E
QS7
QS8
QS9
. . . . . . .
. . . . . . .
.
. . .
. .
.
. . . . . .
. . .
.
QSll
. .
. . .
.
. .
QSl2
QS73
. .
. . . . .
. .
sp. A
species could be recognized. With the exception of four carapaces belonging questionably to Cytherellina Jones and Hall, 1969, a genus of controversial systematic position (Casier et al., 1992), the ostracod species identified belong exclusively to the palaeocopids and the podocopids. The species, listed in terms of decreasing abundance, are: Fameneila n. sp. A, aff. perspiqua Rozhdestvenskaja, 1972; lndivisia aff. baschkirica Rozhdestvenskaja and Tschigova, 1972; and Tchizhovaella n. sp. A, aff. regina Lethiers, 1978. Knoxie//a cf. domanica Rozhdestvenskaja, 1972; Famenella cf. bisangulata Lethiers, 1981; and Serenida dushanensis (Shi, 1964) are more rare. Ochescapha cf. tichomirovi (Tschigova, 1963); Ochescapha sp. A; Knoxiella sp. A aff. compressa Rozhdestvenskaja, 1972; Orthocypris cf. exemplaris Rozhdestvenskaja, 19722; four species of Bairdia MC Coy, 1944; and Acratia sp. A are extremely rare.
IV. Interpretation The ostracod assemblage occurring in the Frasnian/Famennian boundary beds of the Lijiaping section is distinctly dominated by ostracods belonging to the Kloedenellacea (54% of specimens), and by the genus Famenella Polenova, 1953 (39%). Affinities seem to be greater with species previously described from Famennian rather than from Frasnian deposits, and the assemblage is C. R. Acad. Sci. 1997. 325,433-438
transition
D
cf. tichomirovi
Bairdia
Frasnian/Famennian
C
.
afi
the
boundary
Frasnien/Famennien
QS3
cf. domanica
Tchizhovaella
Baird/a
de la limite
indet.
Famenella n. sp. A, Bairdia
Frasnian/Famennian
Q-51
indet
Kloedenellacea Knoxiella
the
A
designation
Podocopida
Acratia
across
from
Paris,
Sciences
de
la terre
et des
plan&tes
/ Earth
not characteristic of oxygen-depleted water conditions. In fact, the occurrence of several species of podocopids, which are deposit feeders, indicates well-oxygenated conditions on the sea floor during at least brief intervals (Lethiers and Whatley, 1994). The relative proportion of filter-feeding ostracod species in comparis’on with depositfeeding ones, therefore, suggests an oxy:gen level about 3.5-4.5 mL/L O2 for beds C and D. Very abundant individually, but poorly diversified assemblages indicate semi-restricted conditions in the Eifelian ecotype of Becker (Bandel and Becker, 1975). Such “impoverished” assemblages occur in the lowermost Famennian beds in several Belgian sections at the southern border of the Dinant Basin, the type area for the Frasnian and Famennian stages. At Sinsin and Lambermont, nested ostracod valves are common, suggesting very shallow-water conditions (Casier and Devleeschouwer, 1995). In the former stratotype section for the Frasnian/Famennian boundary at Senzeille, however, such apparently shallowwater ostracod assemblages occur in sediments indicative of deeper-water settings. Consequently, it is concluded that the recovery of the ostracod fauna after the mass extinction event began in the southern border of the Dinant Basin, with species sheltered in very shallow-water environments and which were not affected by the irlflux of oxygendepleted water on the shelf. Moreover, this process of recovery has been also suggested for ostracods in the new & Plunetory
Sciences
J.-G.
Casier et al.
Frasnian/Famennian boundary stratotype section and point (CSSP) at Coumiac in southern France (Lethiers and Casier, 1996a) and in the famous Devils Gate Pass section in Nevada of the western United States (Casier and Lethiers, 1997). In the upper quarry at Coumiac, the Frasnian/Famennian boundary has been placed directly above a 12 cm thick grey, coarse-grained dolomitic limestone (Klapper et al., 1994). This bed is believed to be equivalent to the German Upper Kellwasser Limestone (Becker et al., 1989), a limestone deposited under hypoxic conditions in the Harz Mountains of Germany. These oxygen-depleted conditions are considered to be at least partially responsible for the mass extinction and, at Coumiac, more than 75% of the ostracod fauna disappeared close to the base or
Acknowledgements: We sincerely thank C. Sandberg of the United University of Saskatchewan, Saskatoon, for reviewing the manuscript.
within this boundary unit. The recovery tion began immediately above.
from the extinc-
By comparison, we conclude that the ostracod fauna occurring in beds C and D in the Lijiaping section represents the first indication that the ostracod fauna had recovered from the Late Devonian extinction in Hunan. Consequently, the Frasnian/Famennian boundary would be better placed between unit B and C in the Lijiaping section, rather than between units D and E as originally determined. In fact, the chemical composition of the yellow-coloured clay that constitutes the B unit allows for several interpretations such as e.g. a bentonite layer, or a layer that underwent intense subaerial weathering (Hou et al., 1996) indicating a major unconformity and so on.
States
Geological
Survey,
Denver
and
W.K. Braun
of the
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