Statistical analysis
The CONISS cluster analysis allows the zoning of the different units of palynofacies in the different samples of the Gomati River flood plain. However, to ascertain the extent of the role of grain size in palynofacies, coordination statistics Principal Component Analysis (PCA) was performed on grain size and palynofacies. The PCA technique is widely used by ecologists and environmentalists to convert large data sets into condensed principal components of representative forms in two-dimensional presentation (Legendre and Legendre, 1998).
The statistical Response data in the present study are compositional and have a gradient of 1.0 standard deviation. According to the CANOCO Advisor linear method (PCA) is recommended (Legendre and Legendre, 1998). In the present study, based on the PCA technique, it can be ascertained that the relation between palynofacies and grain size accounted for 84.62% of the four principal components, however, the two principal components PC1 and PC2 accounted for 62% of the total variance. The Pseudo-canonical correlation corresponds to ~81.48% for PC1 and PC2. The study shows that PC1 is mainly correlated with medium silt and fine sand (left to the right side of Fig. 6) where the degraded brown OM, structured OM, oxidized land plant remains and cyanobacteria tend to have dominance or enhanced percentage, and with coarse sand (in opposite direction) where only Black oxidized OM follow the direction of probability. In PC1 the fine silt and medium silt are relatively short and have less impact on the distribution of the palynofacies. Similarly, for PC2 it can be observed that Pollen/spore, Amorphous OM, and filamentous algae go in the same direction as very fine sand. This explains how the palynofacies are in synchronization with very fine sand in increasing probability as also observed by the association of palynofacies and grain size (Tyson, 1993). Similar to clay sediments, the fungal remains, animal remains, and scolecodonts go in hand-to-hand. A negative correlation among the different palynofacies can be observed such as animal remains with pollen/spore, filamentous algae, and Thecamoebians. The black oxidized OM also shows a negative correlation with degraded brown OM, structured OM, and oxidized land plants.