Foraminiferal Stratigraphy and Paleoenvironments of Late Jurassic to Early Cretaceous Deposits in Thakkhola, Nepal

Agglutinated foraminifera from the Northern Tarcău Nappe (Eastern Carpathians, Romania)

“…Due to the reduced dimensions of the species, they were associated to rapidly disturbed or varying environments indicating increased circulation of the bottom waters, a low sedimentation rate, oxygenated waters and oligotrophic conditions at the sea floor (Bąk, 2004). The regular sized specimens in our samples match the hypothesis of Nagy et al (1997) who state that the elongate subcylindrical forms live in a deep infaunal habitat with increased organic flux and higher nutrient supply; they scavenge the sediment for bacteria and detritus (Nagy, 1992;Nagy et al, 1995). They are most common in inner shelf to upper bathyal environments with moderate contributions in lagoonal and marsh environments (Nagy et al, 1995).…”

“…These species belong to the M3a morphogroup of Kaminski and Gradstein (2005). Recent similar assemblages have been reported from marginal marine environments (marshes and lagoons) (Nagy et al, 1995). The numerous specimens of Glomospira make possible the correlation with similar Eocene (Ypresian/ Lutetian) deposits from the Polish Carpathians, Morocco and Labrador (Morgiel and Olszewska, 1981;Morgiel and Olszewska, 1982;Kaminski et al, 1989;Kaminski et al, 1996).…”

“…Morphogroup analysis is based on the assumption that the morphology of the foraminiferal test is connected to the feeding strategy of benthic taxa, and therefore with their microhabitat preferences. Other authors like Nagy (1992), Nagy et al, (1995), Bąk et al, (1997), Van der Akker et al, (2000), Kaminski and Gradstein (2005), Cetean et al, (2011), further refined and enhanced the morphogroup analyses based on agglutinated foraminifera for palaecological interpretation. Quaternary,, , 17 -faults, 18 -digitations, 19 -anticline (symmetrical, overturned), 20 -syncline (symmetrical, overturned), 21 -location of the investigated sections.…”

Small-sized <i>Trochammina</i> assemblages in deep-water Eocene flysch deposits (Outer Carpathians, Poland) and their palaeoecological implications

“…It is possible to estimate palaeoecological parameters of the assemblage, indicating its depositional environment on the basis of the test shape, as has been previously shown by Jones & Charnock (1985) with later modifications (see Murray et al, 2011 and papers cited therein). This has been successfully used for palaeontological analysis of Mesozoic and Cenozoic palaeoenvironments (Coccioni & Galeotti, 1994;Nagy et al, 1995;Bąk et al, 1997;Peryt et al, 1997;Mancin, 2001;Waśkowska-Oliwa & Leśniak, 2003;Bąk, 2004;Kender et al, 2008;Setoyama et al, 2011).…”

“…Numerous reports in the literature refer to the mass appearances of smallsized Trochammina in shallow-water environments, where the dominance of this taxon is associated with stressful environmental conditions, such as reduced salinity, oxygen hypoxia, stormy environments, after earthquakes, low or high TOC values (Nagy et al, 1988(Nagy et al, , 2010Hollis et al, 1995;Rasmussen et al, 2003;Barbosa et al, 2005;Hawkes et al, 2010;Hromic et al, 2012). It is also common in brackish environments (Jones, 1988;Nagy et al, 1995). Trochammina is considered to be an opportunistic form (Scott et al, 1983;Murray, 1991;Nagy et al, 1995), which can create well-functioning associations in marsh environments that are unfavourable for other foraminifera.…”