The Evolutionary Characteristics of Lower Permian Keziliqiman Reefs in the Southwest Margin of Tarim Basin, Northwest China

Figure 14

CL characteristics of the reef. In (a) and (b) (reef base), Tubiphytes-wrapped bioclasts, with burrow holes visible locally (emitting very weak brownish red light, indicated by blue arrows), produce very weak brownish red light (indicated by green arrows). Dissolution pores are well developed, with calcite cement at the edge; the core part of the cement is nonluminescent while its edge is bright (indicated by yellow arrows). In (c) and (d) (the lower zone of the reef core), sea urchin spines (in oblique sections), cut by fractures (calcite in them does not emit light), can be seen. The upper part of sea urchin spines is nonluminescent, while the lower part sends out medium orange red light (recrystallized). In (e) and (f) (the upper zone of the reef core), the cavities of bryozoans are filled by micritic and sparry cement. The micritic fillings are weakly brownish red (indicated by yellow arrows), and the sparry fillings (recrystallized) very weakly brownish red or non-luminescent (indicated by green arrows). In addition, two generations of cement (indicated by the white arrow) can be seen in the spines. In (g) and (h) (back reef), the clasts of brachiopods and Colospongia can be seen, whose bones do not emit light (indicated by yellow arrows). The stem pores of Brachiopods and the abdominal cavities of sponges are filled by micrite, and the micrite that fill abdominal cavities of sponges are partially recrystallized, giving off weak red light. In (i) and (j) (back reef), Ptilodictyina are symbiotic with echinoderms. Ptilodictyina do not radiate light, while echinoderms medium orange light. In (k) and (l), cavities of Kepingophyllidae are filled by micrite and spar; the axes of the septa emit orange light of medium-strong intensity; the feathery clasts on both sides of the septa brown red light of weak intensity; the positions near the axes of the septa are basically not luminescent. In (m) and (n) (front reef), intergranular dissolution pores are filled by sparry cement, whose luminescence is dimmer than that of the surrounding micritic matrix. In (o) and (p), Fenestella are symbiotic with echinoderms; echinoderms are not luminescent, while Fenestella bright red.

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