A. Leherisse et al., STRATIGRAPHIC AND PALEOGEOGRAPHIC SIGNIFICANCE OF SILURIAN ACRITARCHSFROM SAUDI-ARABIA, Review of palaeobotany and palynology, 89(1-2), 1995, pp. 49-74
Abundant and well-preserved acritarchs of Early Silurian and late Midd
le to Late Silurian age have been obtained from marine subsurface sequ
ences in seven exploratory wells drilled by the Saudi Arabian Oil Comp
any in central and northwestern parts of Saudi Arabia. Preliminary res
ults on their stratigraphic distribution allow an informal zonation of
9 regional acritarch assemblages zones to be proposed. Correlations a
re made between the different local wells studied, and with contempora
neous assemblages described elsewhere. During the Silurian, Saudi Arab
ia occupied an intermediate to high latitudinal position, on the easte
rn part of the Gondwana margin. This paleogeographic situation may exp
lain the mixture of taxa known from Western European (Balto-Scandinavi
a) and North American sequences, with species that have hitherto been
recorded only from North Africa or South America in the high-latitude
province. A local distinctive endemic microflora is also represented.
This additional record of Silurian acritarchs from Northern Gondwana i
s of considerable importance concerning the biostratigraphic and paleo
geographic implications. The distribution of acritarchs shows distinct
geographic patterns that may be attributed to climatic factors, ocean
ic circulation pattern, and/or related to local environmental paramete
rs. In the systematic part, eleven new species of acritarchs, Anomalop
laisium johnsium, Baltisphaeridium diabolicum, Buedingiisphaeridium in
certum, Dactylofusa horrida, Goniosphaeridium versatile, Goniosphaerid
ium sp. A, Leiofusa cucumis, Multiplicisphaeridium circumscriptum, Neo
veryhachium carminae constricta, Veryhachium strangulatum, Visbysphaer
a glabra, and one new genus and species of coenobial Algae, Kahfia ara
bica, are described and illustrated.