Dokumentirali smo ostanke jam v dolomitizirani formaciji Seroe Domi na otoku Curaçao in raziskova... more Dokumentirali smo ostanke jam v dolomitizirani formaciji Seroe Domi na otoku Curaçao in raziskovali njihov nastanek. Petrografske analize zbruskov ter geokemiče analize površinskih izdankov in vzorcev jamskih sten, potrjujejo predhodno domnevo o izvoru (replacement) dolomita v območju mešanja slane in sladke vode. Analiza stabilnih izotopov kaže na prenos tekočin iz bazaltne podlage vzdolž mreže razpok v formaciji Seroe Domi. Oblika večine jam kaže, da gre za dele freatičnih sistemov, odkrili pa smo tudi več psevdokraških pojavov. Morfološke značilnosti jam in njihova nadmorska višina sta nam omogočili oceno minimalne hitrosti umikanja otoških klifov, ki je med 5 m in 52 mm na tisoč let. Ostanki jam, ki so bili prej največkrat spregledani, so kazalci diagenetskih dogodkov v formaciji Seroe Domi in vsebujejo druge pomembne informacije, če jih le postavimo v ustrezen geološki okvir. Ključne besede: Jame tipa "flank margin", dolomitizacija, formacija Seroe Domi, Curaçao.
Photosynthetic characteristics of two low-altitude and two high-altitude populations of the broad... more Photosynthetic characteristics of two low-altitude and two high-altitude populations of the broad-leaved cattail (Typha latifolia L.) were compared. Light-saturation characteristics and light-saturated rates in normal air were identical. Although carbon dioxide saturation ...
ABSTRACT On 17 21 February, a meeting entitled, "Paleokarst Field Conference: Macroscopi... more ABSTRACT On 17 21 February, a meeting entitled, "Paleokarst Field Conference: Macroscopic Dissolution Features in the Rock Record," was held at the Bahamian Field Station on San Salvador Island, Bahamas. The conference was sponsored by the Karst Waters Institute as the 14th Friends of Karst meeting. The conference drew the maximum limit of 41 participants, from eight countries. The majority of participants were from the United States, but a contingent of nine came from Canada.
Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using ma... more Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using mathematical models. Today, armed with an array of orbiting and fly‐by satellites and survey instrumentation, we have now acquired cave data across our solar system—including the identification of potential cave entrances on the Moon, Mars, and at least nine other planetary bodies. These discoveries gave rise to the study of planetary caves. To help advance this field, we leveraged the expertise of an interdisciplinary group to identify a strategy to explore caves beyond Earth. Focusing primarily on astrobiology, the cave environment, geology, robotics, instrumentation, and human exploration, our goal was to produce a framework to guide this subdiscipline through at least the next decade. To do this, we first assembled a list of 198 science and engineering questions. Then, through a series of social surveys, 114 scientists and engineers winnowed down the list to the top 53 highest priority...
The Holocene/ late Pleistocene contact is sharp and well exposed at many places along the rocky w... more The Holocene/ late Pleistocene contact is sharp and well exposed at many places along the rocky windward (east) coast of Long Island. These cliffs are located immediately south of Coral Gardens (Stop 5). Here transgressive-phase carbonate eolianite beds of the North Point Member of the Rice Bay Formation overlie regressive-phase eolianite beds of the Cockburn Town Member of the Grotto Beach Formation. View is looking north toward Coral Gardens. Photo by Al Curran.
San Salvador (Bahamas) is a carbonate island with dozens of flank margin caves formed in the phre... more San Salvador (Bahamas) is a carbonate island with dozens of flank margin caves formed in the phreatic zone by fresh seawater mixing within the freshwater lens. These caves have no direct connection with the sea, and form at or close to the tidally influenced fluctuating water table. After sea-level fall, in their subaerial parts caves are enlarged mainly by rock dissolution and by erosion close to the water level, condensation-corrosion and breakdown processes. For understanding the geomorphological features observed in these caves and how they are related to light attenuation, we investigated three sampling sites in the tidally influenced zone of Lighthouse Cave, which has been re-invaded by seawater during the Holocene sea-level highstand. A freshwater lens no longer exists within or adjacent to the cave. Rock samples were collected above and below the internal lake shores close to the entrance, and in the twilight and dark zones of this cave. Light and electron microscopy examinations were conducted for detecting microbial cells, as well as bioconstruction and bioweathering features. In addition, a high precision laser scanner was used for characterising Postprint of: Geomorphology 354: 107054 (2020) sample microtopography. Our data showed that the microtopography and geomorphology of the lake shore samples (cave entrance) are dominated by bioweathering, whereas the samples of the twilight and dark zones are controlled by a combination of both bioweathering and bioconstructive processes depending on light availability. Bioconstructive structures, such as semi-planar lamination, at the fluctuating water level of the Lighthouse Cave show that dissolution due to water mixing of sea and freshwater in the Holocene is no longer the most important speleogenetic process. We propose that the geomorphological evolution is strongly influenced by the degree of rock diagenesis more than the initial mechanism of speleogenesis.
Coastal karst cave development globally is biased towards the tropics and subtropics, where carbo... more Coastal karst cave development globally is biased towards the tropics and subtropics, where carbonate deposition is ongoing, and therefore carbonate coasts are common. The Carbonate Island Karst Model (CIKM) delineates the unique conditions that separate coastal karst from traditional karst areas of continental interiors. In these warm-water carbonate islands, diagenetically immature, or eogenetic carbonate rocks are host to a fresh-water lens that creates flank margin caves in a diffuse flow environment. Diagenetically mature, or telogenetic carbonates, can also host flank margin caves. Flank margin caves can form rapidly, as carbonate sediment is deposited, to produce syndepositional caves called banana holes. Flank margin caves can survive as open voids for millions of years, and as infilled diagnostic features for tens of millions of years. Vadose fast flow routes called pit caves form as a result of surface micritization to provide point recharge to the fresh-water lens. The presence of non-carbonate rocks can perch vadose flow, creating stream caves that terminate in the fresh-water lens. When sea level falls to create large exposed carbonate platforms, phreatic conduit flow develops to carry recharge to the platform periphery. Collapse of these conduits, as well as bank margin fracture, account for the majority of blue holes in carbonate platforms. Closed depressions in eogenetic carbonate islands are commonly constructional, relicts from variable carbonate deposition. The most common sinkhole type is the cave-collapse sinkhole. Morphometric analysis of flank margin caves supports cave origin as the amalgamation of individual chambers, provides evidence of denudation rates, and can differentiate flank margin caves from some pseudokarst cave types.
Terrestrial and shallow marine geology of the Bahamas and Bermuda, 1995
Page 1. Geological Society of America Special Papers doi: 10.1130/0-8137-2300-0.77 1995;300;77-90... more Page 1. Geological Society of America Special Papers doi: 10.1130/0-8137-2300-0.77 1995;300;77-90 Geological Society of America Special Papers Frances M. Hagey and John E. Mylroie Pleistocene lake and lagoon deposits, San Salvador Island, Bahamas ...
Glaciolacustrine lithofacies deposited during the Wisconsin glaciation were found in eight pre-gl... more Glaciolacustrine lithofacies deposited during the Wisconsin glaciation were found in eight pre-glacial caves inundated by Glacial Lake Schoharie located in the Helderberg Plateau region of Schoharie County in central New York. The lithofacies consisted of three individual facies, referred to collectively as a ‘sediment package’, which are stratigraphically uniform with the middle facies in sharp contact with the facies directly above and below. The packages found in the eight caves all displayed a similar stratigraphic sequence, from bottom to top: tan/white and or light grey, very thinly bedded, silts and clays overlain by poorly sorted, matrix-supported gravels overlain by dark brown very thinly bedded silts and clays. Laboratory analyses of 63 sediment samples from all eight caves displayed varying weight percents of the organic content of each sample. However, the analyses indicated a higher concentration of fine-grained calcite material in the tan/white and light grey facies th...
Dokumentirali smo ostanke jam v dolomitizirani formaciji Seroe Domi na otoku Curaçao in raziskova... more Dokumentirali smo ostanke jam v dolomitizirani formaciji Seroe Domi na otoku Curaçao in raziskovali njihov nastanek. Petrografske analize zbruskov ter geokemiče analize površinskih izdankov in vzorcev jamskih sten, potrjujejo predhodno domnevo o izvoru (replacement) dolomita v območju mešanja slane in sladke vode. Analiza stabilnih izotopov kaže na prenos tekočin iz bazaltne podlage vzdolž mreže razpok v formaciji Seroe Domi. Oblika večine jam kaže, da gre za dele freatičnih sistemov, odkrili pa smo tudi več psevdokraških pojavov. Morfološke značilnosti jam in njihova nadmorska višina sta nam omogočili oceno minimalne hitrosti umikanja otoških klifov, ki je med 5 m in 52 mm na tisoč let. Ostanki jam, ki so bili prej največkrat spregledani, so kazalci diagenetskih dogodkov v formaciji Seroe Domi in vsebujejo druge pomembne informacije, če jih le postavimo v ustrezen geološki okvir. Ključne besede: Jame tipa "flank margin", dolomitizacija, formacija Seroe Domi, Curaçao.
Photosynthetic characteristics of two low-altitude and two high-altitude populations of the broad... more Photosynthetic characteristics of two low-altitude and two high-altitude populations of the broad-leaved cattail (Typha latifolia L.) were compared. Light-saturation characteristics and light-saturated rates in normal air were identical. Although carbon dioxide saturation ...
ABSTRACT On 17 21 February, a meeting entitled, "Paleokarst Field Conference: Macroscopi... more ABSTRACT On 17 21 February, a meeting entitled, "Paleokarst Field Conference: Macroscopic Dissolution Features in the Rock Record," was held at the Bahamian Field Station on San Salvador Island, Bahamas. The conference was sponsored by the Karst Waters Institute as the 14th Friends of Karst meeting. The conference drew the maximum limit of 41 participants, from eight countries. The majority of participants were from the United States, but a contingent of nine came from Canada.
Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using ma... more Nearly half a century ago, two papers postulated the likelihood of lunar lava tube caves using mathematical models. Today, armed with an array of orbiting and fly‐by satellites and survey instrumentation, we have now acquired cave data across our solar system—including the identification of potential cave entrances on the Moon, Mars, and at least nine other planetary bodies. These discoveries gave rise to the study of planetary caves. To help advance this field, we leveraged the expertise of an interdisciplinary group to identify a strategy to explore caves beyond Earth. Focusing primarily on astrobiology, the cave environment, geology, robotics, instrumentation, and human exploration, our goal was to produce a framework to guide this subdiscipline through at least the next decade. To do this, we first assembled a list of 198 science and engineering questions. Then, through a series of social surveys, 114 scientists and engineers winnowed down the list to the top 53 highest priority...
The Holocene/ late Pleistocene contact is sharp and well exposed at many places along the rocky w... more The Holocene/ late Pleistocene contact is sharp and well exposed at many places along the rocky windward (east) coast of Long Island. These cliffs are located immediately south of Coral Gardens (Stop 5). Here transgressive-phase carbonate eolianite beds of the North Point Member of the Rice Bay Formation overlie regressive-phase eolianite beds of the Cockburn Town Member of the Grotto Beach Formation. View is looking north toward Coral Gardens. Photo by Al Curran.
San Salvador (Bahamas) is a carbonate island with dozens of flank margin caves formed in the phre... more San Salvador (Bahamas) is a carbonate island with dozens of flank margin caves formed in the phreatic zone by fresh seawater mixing within the freshwater lens. These caves have no direct connection with the sea, and form at or close to the tidally influenced fluctuating water table. After sea-level fall, in their subaerial parts caves are enlarged mainly by rock dissolution and by erosion close to the water level, condensation-corrosion and breakdown processes. For understanding the geomorphological features observed in these caves and how they are related to light attenuation, we investigated three sampling sites in the tidally influenced zone of Lighthouse Cave, which has been re-invaded by seawater during the Holocene sea-level highstand. A freshwater lens no longer exists within or adjacent to the cave. Rock samples were collected above and below the internal lake shores close to the entrance, and in the twilight and dark zones of this cave. Light and electron microscopy examinations were conducted for detecting microbial cells, as well as bioconstruction and bioweathering features. In addition, a high precision laser scanner was used for characterising Postprint of: Geomorphology 354: 107054 (2020) sample microtopography. Our data showed that the microtopography and geomorphology of the lake shore samples (cave entrance) are dominated by bioweathering, whereas the samples of the twilight and dark zones are controlled by a combination of both bioweathering and bioconstructive processes depending on light availability. Bioconstructive structures, such as semi-planar lamination, at the fluctuating water level of the Lighthouse Cave show that dissolution due to water mixing of sea and freshwater in the Holocene is no longer the most important speleogenetic process. We propose that the geomorphological evolution is strongly influenced by the degree of rock diagenesis more than the initial mechanism of speleogenesis.
Coastal karst cave development globally is biased towards the tropics and subtropics, where carbo... more Coastal karst cave development globally is biased towards the tropics and subtropics, where carbonate deposition is ongoing, and therefore carbonate coasts are common. The Carbonate Island Karst Model (CIKM) delineates the unique conditions that separate coastal karst from traditional karst areas of continental interiors. In these warm-water carbonate islands, diagenetically immature, or eogenetic carbonate rocks are host to a fresh-water lens that creates flank margin caves in a diffuse flow environment. Diagenetically mature, or telogenetic carbonates, can also host flank margin caves. Flank margin caves can form rapidly, as carbonate sediment is deposited, to produce syndepositional caves called banana holes. Flank margin caves can survive as open voids for millions of years, and as infilled diagnostic features for tens of millions of years. Vadose fast flow routes called pit caves form as a result of surface micritization to provide point recharge to the fresh-water lens. The presence of non-carbonate rocks can perch vadose flow, creating stream caves that terminate in the fresh-water lens. When sea level falls to create large exposed carbonate platforms, phreatic conduit flow develops to carry recharge to the platform periphery. Collapse of these conduits, as well as bank margin fracture, account for the majority of blue holes in carbonate platforms. Closed depressions in eogenetic carbonate islands are commonly constructional, relicts from variable carbonate deposition. The most common sinkhole type is the cave-collapse sinkhole. Morphometric analysis of flank margin caves supports cave origin as the amalgamation of individual chambers, provides evidence of denudation rates, and can differentiate flank margin caves from some pseudokarst cave types.
Terrestrial and shallow marine geology of the Bahamas and Bermuda, 1995
Page 1. Geological Society of America Special Papers doi: 10.1130/0-8137-2300-0.77 1995;300;77-90... more Page 1. Geological Society of America Special Papers doi: 10.1130/0-8137-2300-0.77 1995;300;77-90 Geological Society of America Special Papers Frances M. Hagey and John E. Mylroie Pleistocene lake and lagoon deposits, San Salvador Island, Bahamas ...
Glaciolacustrine lithofacies deposited during the Wisconsin glaciation were found in eight pre-gl... more Glaciolacustrine lithofacies deposited during the Wisconsin glaciation were found in eight pre-glacial caves inundated by Glacial Lake Schoharie located in the Helderberg Plateau region of Schoharie County in central New York. The lithofacies consisted of three individual facies, referred to collectively as a ‘sediment package’, which are stratigraphically uniform with the middle facies in sharp contact with the facies directly above and below. The packages found in the eight caves all displayed a similar stratigraphic sequence, from bottom to top: tan/white and or light grey, very thinly bedded, silts and clays overlain by poorly sorted, matrix-supported gravels overlain by dark brown very thinly bedded silts and clays. Laboratory analyses of 63 sediment samples from all eight caves displayed varying weight percents of the organic content of each sample. However, the analyses indicated a higher concentration of fine-grained calcite material in the tan/white and light grey facies th...
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