107 



4.6 Processing and Analysis of Additional Royal River Cores 



To clarify the distinction between the pseudo-UDM dredged from the anchorage of 

 the Royal River, and the CDM dredged from the middle reach, three more cores from the 

 Royal River were processed and analyzed. Three cores (RR-6, RR-5, and RR-3), located 

 between the upper and middle zones of the Royal River where the pseudo-UDM and CDM 

 met, were selected from archived cores and were processed at the SAIC Environmental 

 Testing Center (Figures 2-5 and 2-10). All cores consisted of black silty clay, but had an 

 oxidized (gray) exterior. Because of the paucity of microfossils in many of the sediment 

 samples from the upper reach of the Royal River during the original analysis, one of the 

 additional cores (RR-3) was split into two sections to evaluate the effect of the 

 preservative. For this discussion, the sample preserved in formalin is referred to as RR- 

 3F, and the sample preserved in methanol is referred to as RR-3M. 



Mineralogy. The coarse fraction from the top of the cores contained plant parts, 

 wood chips, and shell fragments. Large bivalve moUusca fragments and an intact 

 gastropod were found in Core RR-6. The fine fraction of the cores contained many of the 

 trace components seen previously in the Royal River (Table 4-2; Figure 4-30). Samples 

 RR-3M and RR-3F were identical in terms of mineralogical analysis, and so the data are 

 shown only once on Figure 4-30. Quartz was predominant in all samples with micas 

 common. Black porous material and plant fragments were common at RR-6 and RR-3, 

 and very abundant in RR-5. Dark minerals, flyash, insect parts, and planktonic diatoms 

 were rare. One textured ostracod was found in RR-6. The samples collected from the 

 additional cores were similar in mineralogical composition to surrounding Cores RR-8, 

 RR-15, and RR-26 and represent a combination of the upper and middle region means. 

 Fibrous minerals and bryozoan fragments, indicators of the outer river region, were absent 

 in all cores. Rare shell fragments in the additional cores were more typical of the upper 

 and middle regions than their more common occurrence in the outer region. 



Microfossils. The total number of individual microfossils was higher in the 

 additional cores despite having been stored for over 18 months. Calcareous species 

 (mudflat and shelf calcareous foraminifera, ostracods), however, were reduced in 

 abundance relative to the original Royal River core analyses. This may be due to 

 dissolution of the calcareous specimens (agglutinated species consist primarily of silica). 

 Only Core RR-6 had a significant number of both mudflat and shelf species, which 

 potentially were protected from dissolution by the high concentration of calcium carbonate 

 of large calcareous bivalve fragments embedded in the core. The data from the additional 

 cores, therefore, probably do not represent the acmal calcareous foraminifera or ostracod 

 populations at these sites. 



The Portland Disposal Site Capping Demonstration Project, 1995-1997 



