Taphonomic signatures,ichnofacies analysis and depositional dynamics of fossil macro-invertebrate assemblages of the San Juan Raya Formation,Zapotitlán Basin,Puebla, Mexico

In this paper, we describe the taphofacies and ichnofacies from Aptian strata of the San Juan Raya Formation in the Santa Ana Teloxtoc area, Puebla, Mexico. A composite stratigraphic section was analysed on a bed-by-bed scale up to a total thickness of 765.5 m. Our results show the presence of 10 taphofacies and 3 ichnofacies. The taphofacies and ichnofacies interpretation, and its correlation with the sedimentary lithofacies, enabled the determination of a palaeoenvironmental model for the study area that corresponds to a shallow marine, open-coast, clastic system with episodic sedimentation as a product of storm events. This system had several variations in sub-environments, from foreshore to offshore. Foreshore and shoreface environments are characterised by taphofacies Tf1, Tf2, Tf3 and Tf10 and PsI and SkI ichnofacies, representing lower faunal diversity moments (with the exception of Tf3 taphofacies). Meanwhile, taphofacies Tf4, Tf5, Tf6, Tf7, Tf8 and Tf9 were representative of shelf environments and are described as moments of medium-to-high faunal diversity (with the exception of Tf5 taphofacies).     

Effect of irrigation treatments upon the chemical constituents ofHibiscus sabdariffa L.

Summary The effects of Se and P on the dry matter yield and chemical composition of Raya (Brassica juncea Cos. var. R.L. 18) were studied in the green-house. The dry matter yield in P treated and untreated pots increased with Se application upto 2.5 ppm. With further increase in Se dose upto 10 ppm, dry matter yield decreased. The increase in P dose from 0 to 50 ppm increased dry matter yield in all Se treated and untreated pots but 100 ppm P rather showed decrease in dry matter yield as compared to 50 ppm P.The Se concentration increased by about 100 fold with the application of 10 ppm Se over 0 ppm Se where P was not added whereas increase was 258 and 336 times when 50 ppm and 100 ppm P was added, respectively. Inorganic, organic and total P increased with increasing Se and P. The increase in inorganic P was more than organic and total P. S and N concentration decreased with increasing Se application and increased with P application.Crude protein showed the same behaviour as N. The total sulphur-containing amino acids (which ranged from 39 to 49% of crude protein) and individual sulphur-containing amino acids like methionine (16.9 tot 20%) cysteine (9.8 to 13%) and cystine (12.3 to 15.9%) decreased with the increasing selenium but increased with increasing phosphorus. N/S ratio in the plant showed significant negative correlation with total sulphur-containing amino acids (r=–0.940^**), methionine (r=–0.951^**), cysteine (r=–0.929^**) and cystine (r=–0.920^*) whereas total sulphur in the plant showed positive significant correlation with methionine (r=0.805^**), cysteine (r=0.924^**) and cystine (r=0.821^**).