Fig. 7 in Recurrent volcanic activity recorded in araucarian wood from the Lower Cretaceous Springhill Formation, Patagonia, Argentina: Palaeoenvironmental interpretations

Fig. 7. Araucarian wood Agathoxylon mendezii sp. nov. (MPM­PB­15596), Estancia El Álamo, Santa Cruz Province, Argentina, Berriasian–Valanginian. Transverse sections observed under LM. A. General aspect showing numerous, at least five frost rings (brackets). B, C. Detail of frost rings. B. Two frost rings. Note normal and rectilinear trajectory of rays (arrows) alternate with more sinuous and distended rays (arrowheads). C. Detail of frost ring cell layers, from inside to outside. Note normal tracheids that gradually grade into irregular shaped tracheids (bar) followed by a dark layer of collapsed dead cells (arrow) followed by a layer of distorted axial tracheids difficult to recognise individually. Also note dark contents in lumen cells. Scale bars: A, 3 mm; B, 1.5 mm; C, 150 µm.