No abstract

The Fulra limestone (middle Eocene) exposed in the areas around Jhadwa and Harudi villages, southwestern, Kachchh reveals presence of a rich assemblage of calcareous algae belonging to the Chlorophyceae and Rhodophyceae along with abundant foraminifera. In the present paper, eight species belonging to eight genera of calcareous algae are described. These include Dissocladella longijangensis, Sporolithon keenani, Corallina crossmanni, Arthrocardia sp. Misra et al. 2001, Lithothamnion ishigakiensis, Melobesioideae gen. et spec. indet. 1, Melobesioideae gen. et spec. indet. 2 and Lithoporella melobesioides. Out of these, one taxon belongs to the family Dasycladaceae. Among the remaining taxa, one taxon to the family Sporolithaceae, three taxa to the family Corallinaceae and three to the family Hapalidiaceae. Two coralline species, Corallina crossmanni and Lithothamnion ishigakiensis, are recorded for the first time from India. Another species (Dissocladella longijangensis), though known from other areas of India, is new to the study area.The dominant group of the calcareous algal association in the study area is represented by non-geniculate coralline algae comprising Hapalidiaceae, Corallinaceae and Sporolithaceae; the minor component is represented by dasyclads (chlorophyceae). These algal groups, together with their growth-forms (arbosescent, encrusting to fruticose, warty), and the associated foraminifera indicate that the depositional environment of the Fulra limestone ranged from deeper innerto mid-ramp environment (40-80 m) in the upper photic zone.

No abstract

The Late and post-Cretaceous succession of larger benthic foraminifera and planktic microfossils from the Shillong Plateau indicates events of extinction and recovery of the biotic forms. These events are interpreted using a conceptual framework involving biological responses to environmental changes caused by eustatic and climatic variations. Stratigraphic distribution shows that the Late Maastrichtian larger benthic foraminiferal assemblage disappears earlier than the planktic microfossils at the boundary interval. After their last occurrence in the Upper Maastrichtian, the larger foraminifera reappears in the carbonates of the Lakadong Formation dated by Glomalveolina primaeva as the Thanetian (P4). The event of the first appearance of larger foraminifera in the Shillong Plateau correlates with zone P4. When compared with other Tethyan sections (e.g., Mediterranean) where they start occurring in the strata equivalent to zone P3b, the event of their reappearance appears to be slightly delayed in the studied section. The P3b zone is the interval marked by the onsetting of habitable conditions on shelves (oligotrophic environments) and is followed by an interval (the equivalent of the P4 zone) of extensive carbonate generation, during which highly diversified larger foraminiferal assemblages evolve and become widely distributed. The Shillong assemblage, therefore, marks the phase of "expanded oligotrophy" in which recovery of carbonate platform environments occurred on a large scale on shallow neritic shelves.

The present paper records nine species of coralline algae from the Prang Formation of middle-late Eocene age from the Jaintia Hills, Meghalaya. The algae are associated with the larger foraminifera including Nummulites, Alveolina and Discocyclina throughout the succession. The temporal distribution of algal species indicates that seven species are known from the Eocene. Of the remaining two, one ranges from the Palaeocene to Eocene and the other is Palaeocene in age. The coralline algae and larger foraminifers are differentiated into two associations, the lower one indicating inner-ramp environment of high energy and the upper one showing deposition in relatively calm waters of deeper ramp environment.