Middle Eocene calcareous algae from Southwestern Kachchh, Gujarat

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.

Coralline algae from the prang formation (middle-late Eocene) of the Lumshnong Area, Jaintia Hills, Meghalaya

“…Remarks: The present pecimens are morphologically similar to those described by Singh et al (2010) from the middle Eocene of Kachchh. The exact generic identification of the present specimens cannot be established due to absence of conceptacles and epithallial cells.…”

“…They were reported from the late Eocene of Northern Italy by Bassi (1998), from the late Eocene of Austrian Molasse zone by Rasser and Piller (1999) and from the middle Eocene of Kachchh, India by Singh et al (2010). Kishore et al (2007) also reported this species from the late Eocene of the South Khasi Hills, Meghalaya, India.…”

Depositional environments and sources for the middle Eocene Fulra Limestone Formation, Kachchh Basin, western India: Evidences from facies analysis, mineralogy, and geochemistry

“…This formation contains a variety of fauna such as larger benthonic foraminifers including Nummulites , Discocyclina , Alveolina , Asterocyclina , and Lepidocyclina , along with rich assemblages of smaller benthonic and planktonic foraminifers; bivalves and echinoids (Jauhri, ; Kachhara et al, ; Samanta, ; Samanta et al, ; Saraswati et al, ; Srivastava et al, ; Tandon & Srivastava, ; Figure ). They are also associated with calcareous nannofossils and calcareous algae (Rai, ; Singh et al, ; Singh & Singh, ). Biostratigraphically, the Fulra limestone has been considered corresponding to Zone NP17 that correlates with part of Zone P13 and Zone P14, Bartonian, the late middle Eocene (Rai, ).…”

“…The entire formation is divided into seven facies and shows dominance of grey to buff coloured, thin to thick (0.5 cm to as thick as 60 cm) ripple laminated, and cross‐bedded, fossiliferous packstone, and grainstone facies in alternation with horizontally‐bedded foraminiferal wackestone and/or packstone facies. Carbonate succession of the Fulra Limestone Formation contains diverse fauna with dominance of foraminiferal assemblages (planktonic and benthonic) and mollusc groups along with the presence of irregular echinoids and calcareous algae in subordinate proportions (Jauhri, ; Kachhara, Jodhawat, & Bigyapati Devi, ; Rai, ; Samanta, ; Samanta, Bandopadhyay, & Lahiri, ; Saraswati, Patra, & Banerji, ; Singh, Kishore, Misra, Jauhri, & Gupta, ; Singh & Singh, ; Srivastava, Gupta, & Jauhri, ; Tandon & Srivastava, ).…”

Sedimentological and geochemical characteristics of the late middle Eocene dolostone succession, Kachchh, western India

“…It mainly consists of carbonate facies that are formed through biochemical precipitation and contains larger benthic foraminifers, such as Nummulites , Discocyclina , Alveolina , Asterocyclina , and Lepidocyclina , along with rich assemblages of smaller benthic and planktic foraminifers, bivalves and echinoids (Jauhri, ; Kachhara, Jodhawat, & Bigyapati Devi, ; Samanta, ; Samanta, Bandopadhyay, & Lahiri, ; Saraswati, Patra, & Banerji, ; D. K. Srivastava, Gupta, & Jauhri, ; V. K. Srivastava & Singh, ; Tandon & Srivastava, ). Besides, it also contains calcareous nannofossils and calcareous algae (for details, see Rai, ; P. Singh & Singh, ; S. K. Singh, Kishore, Misra, Jauhri, & Gupta, ). The microfossil assemblages and calcareous algae reported by previous palaeontologists suggest a middle Eocene age to the FLF.…”