Derek Ford | McMaster University (original) (raw)

Papers by Derek Ford

Many speleothems in caves on Cayman Brac and Isla de Mona have suffered considerable dissolution.... more Many speleothems in caves on Cayman Brac and Isla de Mona have suffered considerable dissolution. It is suggested that this is a consequence of condensation corrosion rather than of aqueous flooding of the entire cave. A program of temperature and relative humidity measurements during the rainy seasons showed that the entrance zones are areas of comparatively large diurnal variation where condensation from warm air onto cooler walls may occur. Artificial condensation was induced using ice bottles: chemical analysis of the condensation waters determined that they were generally undersaturated with respect to calcite and/or dolomite but that this changes over space and time. Gypsum tablets were suspended inside three sample caves on Cayman Brac and one on Isla de Mona for 16 and 13 months, respectively. At the end of this period, tablets close to the entrances and to the floor were found to have undergone considerable dissolution; this could only have been the result of condensation corrosion

Karstologia : revue de karstologie et de spéléologie physique

International Journal of Speleology, 2016

Kalahroud Cave is located in central Iran, ~50 km north of Isfahan. The landscape is a typical mo... more Kalahroud Cave is located in central Iran, ~50 km north of Isfahan. The landscape is a typical mountain desert morphology of cuestas dissected by ravines and gorges created during rare surface runoff events; crest lines are ~2800 m asl and lowlands at ~2100 m asl. Kalahroud Cave (4500 m of mapped passages, ~60 m deep) is entered through breakdown in the eastern wall of a gorge. The host rock is a Cretaceous limestone and mudstone formation 60 m in thickness, underlain by sandstones and conglomerates and overlain by weakly permeable calcareous marl strata, all dipping 15-20 o. Below the entrance breakdown, two corrosion notch chambers give access to a rectilinear, quasi-horizontal maze of joint-guided passages extending ~500 m eastwards. Rock solution morphology created by slowly flowing phreatic waters predominates (solution pockets, partitions, paragenetic forms, etc). Seven shafts are known that discharged water into the maze and chambers from inaccessible passages below. From XRD analysis, the paragenetic sediments derive from the mudstone interbeds. There are small displays of frostwork, helictites and thin flowstones typical of vadose speleothem deposition in arid caves. Below the level of the corrosion notch, more complex sub-aqueous and shelfstone calcites are overlain by accumulations of calcite rafts up to 70 cm in depth. Raft deposition continues today. It is proposed that the cave is of hypogene origin, serving to discharge interformational groundwaters into the gorge, and becoming de-watered as the latter was deepened. The corrosion notches are due to cessation of deepening. From U series dating, the modern phase of raft deposition began about 10,000 years ago. The sequence and ages of older events will be investigated in future work. rectilinear maze, corrosion notch rooms, hypogene cave, calcite rafts, arid climate, Iran

Geological Society of America Special Papers, 2006

Arctic and Alpine Research, 1983

... This is a dra breakdown. Its exploration was abandoned after 800 m. The down vadose canyon en... more ... This is a dra breakdown. Its exploration was abandoned after 800 m. The down vadose canyon entrenched below an initial phreal winter draft blowing up the cave follows the southern canyon, passage. Phreatic form is seen in the ceiling. The canyon is ...

Developments in Earth Surface Processes, 1989