There are five main papers, two short Forum pieces and a Photo Feature in the latest edition of the BCRA’s Cave and Karst Science, but it begins with an extensive tribute to the late Alexander Klimchouk.

Alexander Klimchouk was undeniably one of the most influential cave researchers in the world and this well-deserved appreciation of his life and career does him proud.

Trevor Faulkner has been studying tufa sites in Scotland. Although tufa deposits are uncommon in Scotland, they are ubiquitous on the calcareous island of Lismore in Loch Linnhe, Argyll, especially as exotic varieties on the coasts and in littoral cave entrances and indentations, as previously reported. This paper reports 76 additional sites of cool freshwater tufa deposits on Lismore that have been observed since 2018. This almost doubles the number of known sites, with nearly half of the raised beach on the Main Rock Platform having now been searched for tufa. Tufa is also known in littoral karst caves and notches in other parts of the world, for which recent relevant literature is discussed.

David W. Gill follows up his paper in the previous issue with a more detailed look at factors influencing cave development in Gunung Mulu and Buda National Parks, Sarawak Malaysia. During 37 years of cave exploration and related observations within these parks, it has become apparent that various long-term effects related to vegetation, biodiversity, bats, swiftlets, guano, and atmospheric conditions impact upon cave development and related scientific studies. Notes are presented based upon these years of random observations. Continuation of currently active investigations, augmented by targeted follow-up scientific studies, is recommended, and encouraged.

Sebastian Breitenbach and Norbert Marwan describe a low-cost method of analysing laminated speleothems using ImageJ software. To reconstruct past climate conditions from speleothems, palaeoclimate researchers utilize a variety of advanced but expensive methods, including various stable isotope ratios and trace element analyses. Greyscale changes can be related to growth and matrix density variations in stalagmites, which in turn are probably dependent on drip rate and dripwater Ca-supersaturation, among other factors. Greyscale analysis is particularly helpful where annual layers are found in stalagmites as the greyscale data can be used to build layer-counting chronologies, similar to varve counting in lacustrine and marine sediments. Greyscale information can further be used as a valuable palaeoclimate proxy. Depending on stalagmite growth rate a spatial resolution of less than five micrometres can be obtained, which might translate to seasonal temporal resolution. Here, we present a low-cost and high-resolution method for acquisition and analysis of greyscale data from speleothems by means of the free ImageJ software. We show how greyscale data can be acquired and visualized and describe how proxy time series can be constructed and proxy record uncertainties estimated using numerical methods. Finally, we provide an example for the application of ImageJ for greyscale analysis on stalagmites. The methodology outlined might be of use to geoscientists working on laminated sediments, and speleothems in particular.

Georgios Lazaridis and Despoina Dora have been studying the functional role of Mikri Gourna Cave in the karstic system of Mount Olympus, Greece. Mikri Gourna Cave, which is part of a karst depression in a cirque valley that feeds into the Xerolakki drainage basin, was investigated and monitored for four successive years from 2014 to 2017. Although Mikri Gourna Cave has formerly been considered an ice cave (Lazaridis et al., 2018), fieldwork has since shown that firn accumulation at its deepest point melts during the early autumn. This excludes it from the list of ice caves in Greece and supports an assumption that the annual firn accumulation is a transient aspect of the current climatic regime. Karstic dissolution forms, including scallops, inside the cave indicate an inward flow direction. Scallop analysis suggests a maximum flow velocity of 1.57m/s, which corresponds to the maximum discharge/recharge velocities that occur in a conduit (e.g., Lauritzen, 1989).
The geomorphology of the landscape reveals that the area was occupied by a glacier with distinct retreat phases. Mikri Gourna Cave developed horizontally, with a slightly downward-sloping entrance, located at the lowest point in the rim of a large karst depression. New evidence re-classifies it as a ‘simple dynamic’ cave with firn, active during the Pleistocene glaciation. The term ‘dynamic’ is derived from Luetscher and Jeannin’s (2004) process-based alpine ice cave classification scheme, while the term ‘simple’ refers to its one entrance (Ford and Williams, 2007). The probability that Mikri Gourna functioned as a recharge point to the mountain’s karst system during mainly periglacial periods is strengthened by the estimated maximum flow velocity and associated evidence of inward flow.

Rob Dinnis and fifteen other contributors report on the 2022 excavations at Wogan Cavern, Pembroke, Pembrokeshire, UK. In a previous article in this journal (Dinnis et al., 2022), they described the first season of archaeological excavations at Wogan Cavern. Although based on excavation of a very small volume of deposits, they suggested that the sediments in Wogan Cavern may have very good potential for preserving archaeological remains. Specifically, an intact early Holocene archaeological layer and underlying, bone-bearing Pleistocene deposits encouraged the belief that the cave might be an important early prehistoric site. Here, they provide an update on the previous work, detailing the findings of the 2022 excavation season. The 2022 work identified several phases of historic and prehistoric activity. The early Holocene archaeological layer containing diagnostic Mesolithic artefacts, found previously in the eastern part of the cave, was shown to extend towards the centre of the cave. Stratigraphically lower deposits dating to the Pleistocene, previously demonstrated close to the cave’s eastern wall, were also shown to extend towards the cave’s centre. Excavation of the Pleistocene deposits close to the cave’s eastern wall revealed evidence for human occupation, with one and possibly two Upper Palaeolithic layers present. The archaeological assemblage(s) from these lower deposits bear similarities to the Palaeolithic stone tool assemblage from the famous Paviland Cave, located c.50km to the east. Overall, the 2022 work confirms that Wogan Cavern is an early prehistoric site of national, and potentially international, significance.

In shorter contributions, Martin Laverty and David W. Gill discuss the history of exploration of the caves in the Gunung Mulu and Buda National Parks and Stephen Donovan  has produced some useful notes for those considering writing future articles for publication. The issue rounds up with the first part of Martin Laverty’s photo feature on caves of the Glamorgan Heritage Coast.

Cave and Karst Science is published three times a year and is free to paid-up members of the British Cave Research Association. Members can also read it online here. Non-members may obtain copies for an annual subscription of £40 (plus postage for non-UK destinations), or online access for only £30. A discounted student subscription is available. The publication contains a wealth of information and represents excellent value for money for anyone with an interest in the science of caves. It is well-presented throughout, with a clear, attractive layout and numerous high-quality illustrations.