Fig. 7: Sections of speleothems used in the study with marked growth layers.
From: Arctic speleothems reveal nearly permafrost-free Northern Hemisphere in the late Miocene
Flowstone STBB-I-1 (A); Flowstone STBB-4-2 (B); Folia STBB-4-3 (C); Flowstone STBB-4-5 (D); Flowstones STBB-I-2 (E); STBB-I-6 (F); STBB-II-1 (G); STBB-II-5 (H); STBB-II-7 (I); STBB-I-5 (J); STBB-I-12 (K); STBB-II-2 (L); STBB-II-8 (M); and STBB-II-9 (N). Sampling for X-ray diffraction analysis is marked by red squares. The examples of speleothems’ petrography under the polarizing microscope usually showed the typical columnar crystal structure with no weathering signs, like in flowstone STBB-I-12 (O – cross-polar-light (cpl); P – plain-polar-light (ppl)). In two speleothems, STBB-II-1 and STBB-II-9 along the usual petrography, some weathering signs were found. These include micritization near the surface (STBB-II-1, Q – cpl; R – ppl), or porosity (STBB-II-9, S - cpl, T - ppl). While sampling for chronology, these weathered places were avoided.
