Reassessment of elemental concentration data of sediments from the western delta of the Nile River

Abstract

The present study re-examines geochemical data produced by instrumental neutron activa- tion analysis (INAA) of sixty-two fired clay sed- iment samples from the western Nile delta in Egypt. The goal is to assess the strengths and weaknesses of principal component analysis (PCA) and bivariate data splitting (BDS), two widely used data analysis methods, in success- fully sorting differing sediment chemistries. Both PCA and BDS are performed using vari- ous data formats [i.e. original, calcium (Ca)- corrected, scandium (Sc)-normalized, or loga- rithmically (log10) transformed]. Both PCA and BDS are shown to sort differing chemistries well. While PCA has the advantage of speed, BDS has the advantage of providing specific chemical clarity and the opportunity to assess the degree of sand dilution more precisely. In PCA, the data format is semi-immaterial, while in BDS, different formats of the data may hin- der, rather than enhance, data interpretation, depending on the questions being asked.