The remaining portion of REEs cannot be explained by the combination of detrital minerals
. At the same time, organic matter in oil shale plays an important role in accumulating REEs, particularly HREEs.
Unweathered Teegulines Clay consisted of more than 75% of detrital minerals
including quartz, K-feldspar, kaolinite, chlorite, illite-smectite and chlorite-smectite mixed layers, detrital calcite and phosphate bioclasts, and infratraces of goethite and magnetite.
Arditto (1983) suggested that much of the kaolinite matrix in the Pilliga Sandstone resulted from the post-depositional alteration of unstable detrital minerals
by reaction with mobile groundwater.
The ratio of detrital minerals content to the biogenic matter content in suspension is time depending and rises with the increasing discharge in each river.
The terrigenous detrital minerals predominate over the authigenic minerals in all samples studied.
A variety of C-rich and magnetic particles, shocked quartz grains, and detrital minerals
, including phosphate fragments of brachiopod fossils with dark coatings, have been observed in the ejecta (Puura et al.
In addition, the various morphologies of kaolinite and its distribution in sandstones suggest an interaction between pore water composition and detrital minerals
The terrigenous detrital minerals
mostly comprise quartz and feldspars with a total average content of 35.7%, quartz accounting for 19.1-27.8% (avg.
4, Table 1): (1) dolostone group including 23 samples; (2) dolomitic marlstones represented by 17 samples; (3) the group of mixed carbonate-siliciclastic rocks including 9 cement-rich siltstone samples, 8 cement-supported sandstone samples, 6 samples of dolomitic marlstone rich in detrital minerals
, and 1 dolostone sample, the last one containing abundant detrital-rich interlayers; (4) siliciclastic rocks represented by 23 sandstone and 9 siltstone samples with grain-supported texture.
Figure 2 shows the relationship of the total organic carbon (TOC) content with the contents of clay minerals as well as terrigenous detrital minerals
of oil shale of the Songliao Basin in northeast China.
The qualitative and quantitative X-ray diffraction analysis established that its major minerals include detrital minerals
like quartz and feldspars, with an average content of 45%, as well as clay minerals like kaolinite, andreattite and illite, with an average content of 37% (Table 1).
Coarse-grained detrital minerals
are rare in the Shengli River oil shale; the absorption of finegrained minerals and/or organic matter may be the main mode of occurrence of Rb, Sr, Sm and Nd.