Palynology of the Albian Makhtesh Qatan site, northern Negev (Israel), with descriptions of two new pollen species

Autor: Eckart Schrank
Rok vydání: 2017
Předmět:
Zdroj: Review of Palaeobotany and Palynology. 246:185-215
ISSN: 0034-6667
DOI: 10.1016/j.revpalbo.2017.06.007
Popis: Three levels of an independently dated Early Cretaceous succession in the northern Negev have yielded palynofloras of Albian age. The Afropollis jardinus-Tricolpites-Trisectoris-Qatanipollis Assemblage is from the lowermost level, a shale bed of about 60 cm thickness intercalated in the predominantly fluvial sandstones of the upper Hatira Formation at Makhtesh Qatan (IQ1 locality). The IQ1 palynoflora is dominated by psilatrilete spores, which are interpreted as influx from a fern bog. Altogether 46 formal and informal taxa were identified among the pteridophytic and bryophytic spores of this locality. The gymnosperms yielded 33 taxa including the new species Partitisporites krassilovii. The angiosperms are represented by 36 mono- and triaperturate species including Afropollis jardinus, the new species Foveomonocolpites ravnii and representatives of the genera Foveotricolpites, Qatanipollis, Rousea, Tricolpites and Trisectoris. A middle Albian age of this assemblage is supported by correlation of the IQ1 level with a marine intercalation, the Uza marine tongue of middle-late Albian age and by the stratigraphic position of the IQ1 bed below the ammonite-dated late Albian lower Hazera (Hevyon) Formation at Makhtesh Ramon. Immediately above the dark grey palyniferous IQ1 shale, grey or light grey shales occur, which are either barren or yielded the remains of a weathered, residual palynoflora with freshwater algae such as Botryococcus and Ovoidites. The upper Hatira Formation discussed so far is overlain by the marine carbonates of the Hazera (= Hevyon Formation). The lower part of this formation yielded at Makhtesh Ramon a late Albian ammonite (Hypengonoceras, Lewy), which is associated with an elaterate pollen-bearing assemblage corresponding largely to the Afropollis jardinus–Elaterosporites klaszii Assemblage recovered by the author from the same formation and locality. In contrast to the spore-dominated IQ1 Assemblage, the late Albian palynoflora from Makhtesh Ramon (Miz7/6) is dominated by Classopollis, followed by psilatrilete spores and dinoflagellate cysts. The IQ1 palynoflora reflects high humidity and influence from a vegetation rich in ferns, while the abundance of Classopollis (Cheirolepidiaceae) in the late Albian sample may suggest a shift towards drier conditions.
Databáze: OpenAIRE
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