Morsy, Mohamed A. 
  
düction 1 
puo m APPLICATION OF MULTIVARIATE STATISTICS TO STUDY STREAM SEDIMENT 
ographical DATA FROM THE VICINITY OF LEAD-ZINC OCCURRENCES AT GABAL-RUSAS AREA, 
nonitoring EASTERN DESERT, EGYPT 
Mohamed A. MORSY 
Alexandria University, Egypt 
Geology Department, Faculty of Science 
KEY WORDS: Stream Sediment Survey, Lead-Zinc, Multivariate Statistics, Egypt. 
ABSTRACT 
E Special Sixty-seven stream sediment samples were collected in the vicinity of the Miocene Lead-Zinc 
occurrences near Gabal El-Rusas Area, and analyzed for their Pb, Zn, Cu, Ni, Co, Mn and Fe contents. 
In the present study, statistical cluster and factor analyses revealed useful simplification of the given 
data. Cluster analysis classifies samples into two main groups: the first contains the background 
sing and samples, while the second shows probably mineralized sample group. R-mode factor analysis revealed 
- Remote three dominant factors (R1: Pb-Zn; R2: Co-Mn-Ni-Fe; R3: Co-Mn-Ni) which explained 86% of the 
total information contained in the original geochemical data. Factor R1 is closely related to the lead- 
Zinc occurrences in the area and can be termed the mineralized factor. Factor R2 and R3 are probably 
y of the the result of adsorption and coprecipitation of cobalt and nickel in manganese iron hydroxides (in the 
TION second and third factors). These two factors may account for the main background population, which is 
affected by secondary adsorption effects. 
Planning. 1 INTRODUCTION 
Geochemical surveys using multielement regional stream sediments are important in mineral 
exploration. Such surveys have not only yielded data economic significance but have also provided 
much information of more fundamental interest. So, the sampling of stream sediments is preferred to 
rock or soil sampling as the latter is representative only a relatively small area close to the sample site. 
The stream sediments are generally composed of weathering products introduced into the stream. The 
interpretation of the minor element content within these stream sediments must take into account the 
fact that the data are frequently related to a number of geochemical populations, each of which 
represents geological or geochemical features in the environment. 
As the minor element contents of the stream sediment samples are attributable to the features of 
bedrock, mineralization or secondary environment, it is frequently apparent that many stream sediment 
samples are displaying similar patterns, which indicates considerable repetition of information or data, 
Garrett and Nichol (1969). Cluster and factor analyses are powerful techniques, which overcome the 
above difficulties and are useful in evaluating multivariate geochemical data of various types. 
This paper illustrates the application of cluster and factor analyses as methods of classifying and 
expressing the relationships of the minor element distributions in terms of dominant geochemical 
controls operating in the environment with reference to a multielement drainage survey in Gabal El- 
Rusas area, Eastern Desert, Egypt. 
2 GEOLOGICAL SETTING OF THE AREA 
Numerous geological and geochemical investigations were carried out in the area including Sabet et al. 
(1976), Sabet and Hassan (1978), Morsy (1981 a, b) and Morsy and Hassan (1982). The geological 
section of the Red Sea coastal plain to the south of El Quseir to Mersa Alam is made up of sedimentary 
rocks of Upper Cretaceous, Middle Miocene, Plio-Pleistocene and Quaternary ages lying 
unconformably over late Proterozoic basement rocks. The middle Miocene is well represented in the 
Gabal El-Rusas area. This sequence overlies unconformably the basement complex; the latter is 
composed mainly of igneous and metamorphic rocks in the western part of the area. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 901