I'r - Memorial University of Newfoundland

with the relative contribution ofdifferent primary and secondary sources to the formation
o f the asse mblage. The meaning ofcomponents produced by the PeA for isotop ic
composition was previously explained in the resuJts chapter (see Secti on 4..2.2) and
summarized again in Figure 5.2.2.
5.2 .2 ANTHROPOGENIC SOURCES AND W EATHERING PROCESSES
A generalized pattern involving both molecular and isotop ic composition wasagain
generated through clustering first PCs obtained for both data sets. The percentage oftotal
variance expl ained by each PC in the respective analysis was used in the weighting
procedure performed prior to clustering. Since more detailed analysi s was required to
understan d the inter-relationships between samples and sourc es. the number of clusters in
this case was doubled. For deta iled description ofthe cluste ring procedure the reader is
referred 10 the chaplet dealing with methods (see Section 3.2 .2). The produced cluste rs
(Table 5.2.1: see also Appendix C2) were further plotted in the space offust PCs for
molec ular and isotopic compositions (Fig. S.2.3). In this graph. the horizontal axis is
represented by PC I for molecular composition which was prcviowly assumed 10 reflect
various degree of PAH weathe ring in samples vs. the immediate input ofcompounds
from primary and secondary sources. These relationships are in two expressed by the
relative abundan ce of lower vs. higher molecular weight compo unds in samples and
so urces. The vertical axis demonstrate s relative contribution ofcombustion vs . petroleum
sources reflected by the isotopic composition of compounds and represented by PC I for
isotopic composition. This more detailed approach indicates that although sediments in
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