Morsy, Mohamed A. 
  
  
3 SAMPLING AND ANALYTICAL PROCEDUREDS 
In the investigated area, 67 stream sediment samples were taken during a geochemical survey study. 
Sample spacing was 100 m to 200 m. Each sample consisted of some 100 g of stream sediment. 
Orientation tests revealed that the -1 mm sample fraction and hot extraction with dilute (1:1) 
hydrochloric acid yielded the best analytical results, Morsy (1981a). Analyses of Pb, Zn, Ni, Cu, Co, 
Mn and Fe were carried out by means of Atomic Absorption Spectrometry (Perkin Elmer model 300). 
Analytical precision for all the studied elements is between 14 and 17%. 
4 STATISTICAL TREATMENT OF DATA 
The data obtained were statistically treated, where the calculations of the cluster and factor analyses 
were carried out by using of the SPSS 1986 (Statistical Package for Social Science). The cluster 
analysis was represented by a dendrogram, in which the endpoints of the branches represent the 
samples, and the height at which the branches join corresponds to the sample similarity level for 
admission to pre-existing group. The higher the branches, the more similar are the samples. The 
constructed dendrogram for all the studied samples at Gabal El Rusas area was based on inverse 
distance (d) between these samples. It is evident from this dendrogram that partitioning has separated 
eight samples with anomalously high values for Zn, Pb, Fe, Mn and Ni from the rest samples, which 
themselves form a relatively homogenous group, having essentially background values. From the 
study of the scatter diagrams between zinc versus manganese and iron, it is shown that samples (Nos. 
31,32,33) form a mutual group, which is unlike that of the other samples in composition, since it lies a 
long distance away from them. The second group includes samples (Nos. 29,30,58), which are more 
similar in terms of their zinc and manganese, while the third group includes samples (Nos. 51,52), 
which are close in terms of their high manganese and iron contents. 
5 FACTOR ANALYSIS AND DISCUSSION OF RESULTS 
In recent years many geochemical studies have used factor analysis for reconnaissance and exploration 
work in Egypt, Morsy (1993 & 1997). In the present study, R-mode factor analysis has shown the 
existence of three important factors that can broadly explain the observed variations and distribution of 
elements in the stream sediments of Gabal El Rusas area. Table 1 shows the results of this factor, 
which is concerned with interrelations of among variables, each variable attributes a certain loading to 
each of the extracted factors, which is expressed in the matrix of factor loading. The variance indicates 
the amount of total information contained in each factor. The cumulative variance or total explained 
variance of the three-factors in the area is 86%. 
Table 1. R-mode variomax rotated factor matrix 
  
  
  
  
  
  
  
  
  
  
Communality Factor 3 Factor 2 Factor 1 Variable 
0.9771 0.1181 0.0966 0.9624 Zn 
0.9792 0.1472 0.1259 0.9803 Pb 
0.7940 0.5587 0.6801 0.1388 Ni 
0.8448 0.0391 0.0086 0.0064 Cu 
0.8130 0.7431 0.8504 0.0642 Co 
0.8127 0.7042 0.8124 0.3139 Mn 
0.8001 0.4509 0.5894 0.1213 Fe 
14.77 25.86 45.27 Variance 
  
  
  
  
  
  
902 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.