We present the prokaryotic microbial diversity of Mirror Lake, located at the end of Gilindire Cave (Turkey), whose geomorphology shows development in multiple geologic periods and by multiple mechanisms. The lake comprises brackish water with both fresh and seawater inputs. In total, 5 liters of water was sampled from Mirror Lake and was filtered through a 0.22 µm membrane, and after the DNA isolation, 16S amplicon sequencing was conducted to get whole prokaryotic diversity. The bacterial community of this system is predominately composed of nitrite-oxidizing Nitrospira with a relative abundance of 28 %. We hypothesize that Nitrospira recovered in our samples mediates nitrification by reciprocal feeding with ammonia-oxidizing archaea (Nitrososphaeria). We found Nitrospira had a close association with Planctomycetes CL500-3 clade and Marinimicrobia (SAR406) in the cave habitat, with a relative abundance of 8.3 % and 5.7 %, respectively. To our knowledge, this is the first time that the presence of marine clade SAR324 has been reported from brackish cave waters.
{"title":"16s rRNA diversity of Mirror Lake in Gilindire Cave (Turkey) shows abundant Nitrospira","authors":"Selin Deliceirmak, A. Karahan","doi":"10.4311/2021mb0127","DOIUrl":"https://doi.org/10.4311/2021mb0127","url":null,"abstract":"We present the prokaryotic microbial diversity of Mirror Lake, located at the end of Gilindire Cave (Turkey), whose geomorphology shows development in multiple geologic periods and by multiple mechanisms. The lake comprises brackish water with both fresh and seawater inputs. In total, 5 liters of water was sampled from Mirror Lake and was filtered through a 0.22 µm membrane, and after the DNA isolation, 16S amplicon sequencing was conducted to get whole prokaryotic diversity. The bacterial community of this system is predominately composed of nitrite-oxidizing Nitrospira with a relative abundance of 28 %. We hypothesize that Nitrospira recovered in our samples mediates nitrification by reciprocal feeding with ammonia-oxidizing archaea (Nitrososphaeria). We found Nitrospira had a close association with Planctomycetes CL500-3 clade and Marinimicrobia (SAR406) in the cave habitat, with a relative abundance of 8.3 % and 5.7 %, respectively. To our knowledge, this is the first time that the presence of marine clade SAR324 has been reported from brackish cave waters.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80590272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Christian Stenner, A. Pflitsch, L. Florea, Kathleen Graham, E. Cartaya
Glaciovolcanic cave systems, including fumarolic ice caves, can present variable atmospheric hazards. The twin summit craters of Mount Rainier, Washington, USA, host the largest fumarolic ice cave system in the world. The proximity of fumarole emissions in these caves to thousands of mountaineers each year can be hazardous. Herein we present the first assessment and mapping of the atmospheric hazards in the Mount Rainier caves along with a discussion on the microclimates involved in hazard formation and persistence. Our results are compared to applicable life-safety standards for gas exposure in ambient air. We also describe unique usage of Self-Contained Breathing Apparatus (SCBA) at high altitude. In both craters, subglacial CO2 traps persist in multiple locations due to fumarole output, limited ventilation, and cave morphology. CO2 concentrations, calculated from O2 depletion, reached maximum values of 10.3 % and 24.8 % in the East and West Crater Caves, respectively. The subglacial CO2 lake in West Crater Cave was persistent, with atmospheric pressure as the main factor influencing CO2 concentrations. O2 displacement exacerbated by low O2 partial pressure at the high summit altitude revealed additional cave passages that can be of immediate danger to life and health (IDLH), with O2 partial pressures as low as 68.3 mmHg. Planning for volcanic research or rescue in or around similar cave systems can be assisted by considering the implications of atmospheric hazards. These findings highlight the formation mechanisms of hazardous atmospheres, exploration challenges, the need for mountaineering and public awareness, and the broader implications to volcanic hazard assessment and research in these environments.
{"title":"Development and persistence of hazardous atmospheres in a glaciovolcanic cave system—Mount Rainier, Washington, USA","authors":"Christian Stenner, A. Pflitsch, L. Florea, Kathleen Graham, E. Cartaya","doi":"10.4311/2021ex0102","DOIUrl":"https://doi.org/10.4311/2021ex0102","url":null,"abstract":"Glaciovolcanic cave systems, including fumarolic ice caves, can present variable atmospheric hazards. The twin summit craters of Mount Rainier, Washington, USA, host the largest fumarolic ice cave system in the world. The proximity of fumarole emissions in these caves to thousands of mountaineers each year can be hazardous. Herein we present the first assessment and mapping of the atmospheric hazards in the Mount Rainier caves along with a discussion on the microclimates involved in hazard formation and persistence. Our results are compared to applicable life-safety standards for gas exposure in ambient air. We also describe unique usage of Self-Contained Breathing Apparatus (SCBA) at high altitude. In both craters, subglacial CO2 traps persist in multiple locations due to fumarole output, limited ventilation, and cave morphology. CO2 concentrations, calculated from O2 depletion, reached maximum values of 10.3 % and 24.8 % in the East and West Crater Caves, respectively. The subglacial CO2 lake in West Crater Cave was persistent, with atmospheric pressure as the main factor influencing CO2 concentrations. O2 displacement exacerbated by low O2 partial pressure at the high summit altitude revealed additional cave passages that can be of immediate danger to life and health (IDLH), with O2 partial pressures as low as 68.3 mmHg. Planning for volcanic research or rescue in or around similar cave systems can be assisted by considering the implications of atmospheric hazards. These findings highlight the formation mechanisms of hazardous atmospheres, exploration challenges, the need for mountaineering and public awareness, and the broader implications to volcanic hazard assessment and research in these environments.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89567153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Sobolewski, Christian Stenner, Charlotte Huser, Tobias Berghaus, E. Cartaya, A. Pflitsch
Mount St. Helens, one of the highest-risk volcanoes in the Cascade Volcanic Arc, hosts a novel system of glaciovolcanic caves that has formed around the 2004−2008 lava dome. From 2014 to 2021 a multidisciplinary research team systematically explored and mapped these new caves to ascertain their characteristics. Air and fumarole temperatures, volume flow rates, and wind regimes were also monitored. More than 3.0 km of cave passages have formed in a semicircular pattern in the volcanic crater and provide an opportunity to (1) observe cave development over time, (2) identify low temperature fumaroles as the main driving force for cave formation, (3) verify the impact of seasonal snow accumulation on cave climate, and (4) assess heat distribution in subglacial and subaerial portions of the new lava dome. Glaciovolcanic cave systems on Mount St. Helens are comparatively young (<10 years) and the most dynamic in the Pacific Northwest. Observed cave expansion during the study suggests ongoing genesis and future formation of interconnected systems. However, further expansion may also be limited by increasing fumarole temperatures towards the upper parts of the lava dome, cave instability due to snow overload, or variable subglacial volcanic heat output. New glaciovolcanic cave system development provides a unique barometer of volcanic activity on glacier-mantled volcanoes and to study the subglacial environment. We present the results of eight years of initial study within this dynamic cave system, and discuss a pathway towards future longitudinal analyses.
{"title":"Ongoing genesis of a novel glaciovolcanic cave system in the crater of Mount St. Helens, Washington, USA","authors":"L. Sobolewski, Christian Stenner, Charlotte Huser, Tobias Berghaus, E. Cartaya, A. Pflitsch","doi":"10.4311/2021es0113","DOIUrl":"https://doi.org/10.4311/2021es0113","url":null,"abstract":"Mount St. Helens, one of the highest-risk volcanoes in the Cascade Volcanic Arc, hosts a novel system of glaciovolcanic caves that has formed around the 2004−2008 lava dome. From 2014 to 2021 a multidisciplinary research team systematically explored and mapped these new caves to ascertain their characteristics. Air and fumarole temperatures, volume flow rates, and wind regimes were also monitored. More than 3.0 km of cave passages have formed in a semicircular pattern in the volcanic crater and provide an opportunity to (1) observe cave development over time, (2) identify low temperature fumaroles as the main driving force for cave formation, (3) verify the impact of seasonal snow accumulation on cave climate, and (4) assess heat distribution in subglacial and subaerial portions of the new lava dome. Glaciovolcanic cave systems on Mount St. Helens are comparatively young (<10 years) and the most dynamic in the Pacific Northwest. Observed cave expansion during the study suggests ongoing genesis and future formation of interconnected systems. However, further expansion may also be limited by increasing fumarole temperatures towards the upper parts of the lava dome, cave instability due to snow overload, or variable subglacial volcanic heat output. New glaciovolcanic cave system development provides a unique barometer of volcanic activity on glacier-mantled volcanoes and to study the subglacial environment. We present the results of eight years of initial study within this dynamic cave system, and discuss a pathway towards future longitudinal analyses.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88068155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Briestenský, F. Ambrosino, I. Smetanová, L. Thinová, S. Šebela, J. Stemberk, Lucia Pristašová, C. Pla, D. Benavente
We report the results of 3-years of Radon-222 monitoring in six show caves across Europe, selected with the feature of having only one, or no natural entrance, defined as dead-end caves. The caves are located in Spain, Slovakia, Slovenia, and Czechia. The consecutive monitoring was performed between January 2017 and January 2020. Continuous measurements of the radon activity concentration using spectrometry detection and analysis of the α-particles of 222Rn progeny were performed. Meteorological parameters influencing gas flow were recorded inside and outside of the caves. Although the radon activity concentrations differed from one cave to another, all six of the studied caves revealed very similar trends, showing evident seasonal variability with higher values in summer and lower values in winter. The measured values of radon activity concentrations ranged between 633 and 26,785 Bq/m3. The temperature differences between the inside and outside of the caves is the main radon movements driving force. The results of this study have significant practical implications, making it possible to provide cave administrators with recommendations regarding employee or visitor time-limited access to the investigated caves. Ours is the first comparative study encompassing the most interesting dead-end caves in Europe.
{"title":"Radon in dead-end caves in Europe","authors":"M. Briestenský, F. Ambrosino, I. Smetanová, L. Thinová, S. Šebela, J. Stemberk, Lucia Pristašová, C. Pla, D. Benavente","doi":"10.4311/2021es0101","DOIUrl":"https://doi.org/10.4311/2021es0101","url":null,"abstract":"We report the results of 3-years of Radon-222 monitoring in six show caves across Europe, selected with the feature of having only one, or no natural entrance, defined as dead-end caves. The caves are located in Spain, Slovakia, Slovenia, and Czechia. The consecutive monitoring was performed between January 2017 and January 2020. Continuous measurements of the radon activity concentration using spectrometry detection and analysis of the α-particles of 222Rn progeny were performed. Meteorological parameters influencing gas flow were recorded inside and outside of the caves. Although the radon activity concentrations differed from one cave to another, all six of the studied caves revealed very similar trends, showing evident seasonal variability with higher values in summer and lower values in winter. The measured values of radon activity concentrations ranged between 633 and 26,785 Bq/m3. The temperature differences between the inside and outside of the caves is the main radon movements driving force. The results of this study have significant practical implications, making it possible to provide cave administrators with recommendations regarding employee or visitor time-limited access to the investigated caves. Ours is the first comparative study encompassing the most interesting dead-end caves in Europe.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75531833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dinosaur-bearing Ojo Alamo Sandstone (OAS) of the San Juan Basin (SJB), NM and CO, is earliest Paleocene based on palynologic data from multiple localities. An unconformity of 7-8 m.y. separates the Paleocene OAS from underlying Cretaceous strata in the southern SJB – Maastrichtian-age strata are absent there. Previous publications show that OAS dinosaur bones were not reworked but were fossilized in place. The OAS averages 15-30 m thick in the southern SJB and is up to 130 m thick further north in the basin. The first altered volcanic ash bed ever found in the Nacimiento Fm. was discovered in the southeast SJB 64 m above the top of the OAS near Cuba, NM. Sanidine grains from this ash bed had a 40 Ar/ 39 Ar age of 64.60 Ma (adjusted). Based on an estimated rate of deposition for the lower Nacimiento Fm., the age for the top of the underlying OAS was determined to be 65.7 Ma. Subsequently, a second Nacimiento ash bed was found only 10.5 m above the top of the Ojo Alamo with a reported 40 Ar/ 39 Ar sanidine age of 65.49 Ma . This ash bed was found near De-na-zin Arroyo in the southwest part of the SJB. Again, based on an estimated rate of deposition for the lowermost Nacimiento Fm, the top of the underlying OAS was calculated to be 65.7 Ma. In addition, a detrital sanidine age for the top of the OAS in the southern part of Cuba, NM was reported to be 65.67 Ma, in agreement with the ages above. And a very recent paper (2020) discussing the paleomagnetism of the Nacimiento Fm., suggests an age of 65.67 Ma for the base of magnetochron C29n, a few meters above the top of the OAS. These new data also support an age of 65.7 Ma for the top of the OAS in the southern SJB. Previous publications have estimated the base of the OAS to be ~65.95 Ma, thus the duration of OAS deposition in the southern SJB must have been ~250 k.y. This duration of OAS deposition in the southern SJB of about a quarter-million years is thus confirmed by recent data. It must be cautioned that in those parts of the basin to the north, where the OAS is thicker, the time interval for its deposition could have been proportionally greater and have a younger upper boundary. Some workers (mostly vertebrate paleontologists) have suggested that the OAS consists of two members: a lower, dinosaur-bearing member of Cretaceous age separated from the upper part by an imagined unconformity of millions of years. This report shows that the undivided OAS was deposited over about 250 k.y. in the southern SJB. There is no stratigraphic evidence on OAS outcrops around the basin for a significant break in deposition within this formation; indeed, OAS outcrop observations clearly show otherwise. Voluminous palynologic data, published heretofore, unequivocally support the top-to-bottom Paleocene age for the dinosaur-bearing OAS throughout the SJB. None of these data have ever been falsified.
{"title":"New Evidence Confirms the ~250 K.y. Duration for Deposition of the Paleocene Ojo Alamo Sandstone in the Southern San Juan Basin, New Mexico","authors":"J. Fassett","doi":"10.56577/sm-2022.2829","DOIUrl":"https://doi.org/10.56577/sm-2022.2829","url":null,"abstract":"The dinosaur-bearing Ojo Alamo Sandstone (OAS) of the San Juan Basin (SJB), NM and CO, is earliest Paleocene based on palynologic data from multiple localities. An unconformity of 7-8 m.y. separates the Paleocene OAS from underlying Cretaceous strata in the southern SJB – Maastrichtian-age strata are absent there. Previous publications show that OAS dinosaur bones were not reworked but were fossilized in place. The OAS averages 15-30 m thick in the southern SJB and is up to 130 m thick further north in the basin. The first altered volcanic ash bed ever found in the Nacimiento Fm. was discovered in the southeast SJB 64 m above the top of the OAS near Cuba, NM. Sanidine grains from this ash bed had a 40 Ar/ 39 Ar age of 64.60 Ma (adjusted). Based on an estimated rate of deposition for the lower Nacimiento Fm., the age for the top of the underlying OAS was determined to be 65.7 Ma. Subsequently, a second Nacimiento ash bed was found only 10.5 m above the top of the Ojo Alamo with a reported 40 Ar/ 39 Ar sanidine age of 65.49 Ma . This ash bed was found near De-na-zin Arroyo in the southwest part of the SJB. Again, based on an estimated rate of deposition for the lowermost Nacimiento Fm, the top of the underlying OAS was calculated to be 65.7 Ma. In addition, a detrital sanidine age for the top of the OAS in the southern part of Cuba, NM was reported to be 65.67 Ma, in agreement with the ages above. And a very recent paper (2020) discussing the paleomagnetism of the Nacimiento Fm., suggests an age of 65.67 Ma for the base of magnetochron C29n, a few meters above the top of the OAS. These new data also support an age of 65.7 Ma for the top of the OAS in the southern SJB. Previous publications have estimated the base of the OAS to be ~65.95 Ma, thus the duration of OAS deposition in the southern SJB must have been ~250 k.y. This duration of OAS deposition in the southern SJB of about a quarter-million years is thus confirmed by recent data. It must be cautioned that in those parts of the basin to the north, where the OAS is thicker, the time interval for its deposition could have been proportionally greater and have a younger upper boundary. Some workers (mostly vertebrate paleontologists) have suggested that the OAS consists of two members: a lower, dinosaur-bearing member of Cretaceous age separated from the upper part by an imagined unconformity of millions of years. This report shows that the undivided OAS was deposited over about 250 k.y. in the southern SJB. There is no stratigraphic evidence on OAS outcrops around the basin for a significant break in deposition within this formation; indeed, OAS outcrop observations clearly show otherwise. Voluminous palynologic data, published heretofore, unequivocally support the top-to-bottom Paleocene age for the dinosaur-bearing OAS throughout the SJB. None of these data have ever been falsified.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73985001","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ethan B. Haft, V. McLemore, O. T. R�m�, Jonas Kaare-Rasmussen
Carbonatites are igneous rocks of magmatic origin that are composed of more than 50% carbonate minerals, less than 20% SiO 2 , and they can form economic deposits containing significant amounts of rare earth elements (REE), barite (Ba), fluorite (F), and niobium (Nb). REE are critical minerals and are critical to the functioning of information-age technologies because of their unique properties, i.g., high electric conductivity, strong magnetism, fluorescence, and luminescence. Carbonatites are currently the principal source of REE in the world. Carbonatites in the Lemitar Mountains are light REE enriched and contain as much as ~1% total rare earth elements (TREE). While previously described, new analytical techniques have allowed for additional and more precise description, age, and model of their origin. The Lemitar carbonatites from both 40 Ar/ 39 Ar and U/Pb methods are ~515 Ma. Petrographic observations combined with whole-rock geochemical and isotope data indicate the Lemitar carbonatites are mantle-derived and related to the regional Cambrian-Ordovician belt of alkaline igneous rocks and carbonatites in southern Colorado and New Mexico. The Lemitar carbonatites are not economic at the present time because of small tonnage and low grades. However, drilling is required to determine if they increase in REE and Nb concentrations at depth (1.1% total REE in one sample is significant). Detailed geophysics are required to determine if the Lemitar Mountains could have a larger carbonatite emplaced in the subsurface.
{"title":"Geology of the Cambrian-Ordovician Lemitar Carbonatites, Socorro County, New Mexico: Revisited","authors":"Ethan B. Haft, V. McLemore, O. T. R�m�, Jonas Kaare-Rasmussen","doi":"10.56577/sm-2022.2841","DOIUrl":"https://doi.org/10.56577/sm-2022.2841","url":null,"abstract":"Carbonatites are igneous rocks of magmatic origin that are composed of more than 50% carbonate minerals, less than 20% SiO 2 , and they can form economic deposits containing significant amounts of rare earth elements (REE), barite (Ba), fluorite (F), and niobium (Nb). REE are critical minerals and are critical to the functioning of information-age technologies because of their unique properties, i.g., high electric conductivity, strong magnetism, fluorescence, and luminescence. Carbonatites are currently the principal source of REE in the world. Carbonatites in the Lemitar Mountains are light REE enriched and contain as much as ~1% total rare earth elements (TREE). While previously described, new analytical techniques have allowed for additional and more precise description, age, and model of their origin. The Lemitar carbonatites from both 40 Ar/ 39 Ar and U/Pb methods are ~515 Ma. Petrographic observations combined with whole-rock geochemical and isotope data indicate the Lemitar carbonatites are mantle-derived and related to the regional Cambrian-Ordovician belt of alkaline igneous rocks and carbonatites in southern Colorado and New Mexico. The Lemitar carbonatites are not economic at the present time because of small tonnage and low grades. However, drilling is required to determine if they increase in REE and Nb concentrations at depth (1.1% total REE in one sample is significant). Detailed geophysics are required to determine if the Lemitar Mountains could have a larger carbonatite emplaced in the subsurface.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79000164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A new specimen of the eubaenine turtle Goleremys mckennai from the Paleocene Nacimiento Formation of northwestern New Mexico","authors":"Asher Lichtig, S. Lucas","doi":"10.56577/sm-2022.2806","DOIUrl":"https://doi.org/10.56577/sm-2022.2806","url":null,"abstract":"","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90213767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Acid rock drainage (ARD) occurs when metal sulfide minerals are exposed to surface conditions and begin to oxidize. This creates high concentrations of dissolved iron, other metals, and sulfuric acid, creating orange streams, seeps, and pools. These acidic, metal-rich sites host diverse microbial communities that includes extremophilic iron and sulfur oxidizers that take advantage of the abundant chemical energy from sulfide minerals and dissolved iron, and have adapted to extreme acidity and high metal concentrations. The Copper Flat mine is a historic copper mine located in the Hillsboro mining district in south-central New Mexico. It is a low-grade porphyry deposit where the primary copper mineralization is in the form of chalcopyrite veinlets. The mine operated at full production for 3 months in 1982, and was then placed on a care and maintenance plan to await an increase in the market price of copper, but was eventually decommissioned in the 1990s. At this site, there are two extremely acidic seeps that run only once or twice per year for no more than several weeks at a time, depending on monsoon precipitation. Year after year, a vibrant microbial community springs up when these seeps are actively running. However, we know little about the microorganisms that colonize these seeps, and how the ecology, biogeochemistry, and fate and transport of metals change during these seasonal wetting and drying cycles. Here we present preliminary data the microbial communities present in one of the seeps that was running in June 2020. pH and specific conductivity of the seep varied from 1.54-1.95 and 9.01-6.32 mS/cm, respectively. Based on rRNA gene libraries from nine exploratory samples, seep sediments were dominated by populations related to known lithotrophic iron-and sulfur-oxidizing bacteria, acidophilic organoheterotrophs, diverse algae, and novel Proteobacteria and Thermoplasmatales-group Archaea that varied with the pH and salinity gradients in the seep. Bacteria and archaea related to Leptospirillum, Acidiphilum, Acidibacter, Ferrithrix, Cuniculiplasma , and Ferrimicrobium were consistently more abundant at the more acidic site, while Acidicapsa, Acidobacterium , and Alicyclobacillus dominated at the less acidic location. We hypothesize that these differences in community composition are due to differences in pH and metal content of the waste stream, which may represent the tolerances for each population with respect to their preferred geochemical niches in these ephemeral seeps. Future work aimed at understanding the ecological and geochemical constraints on these organisms can help us to better design passive remediation strategies and understand elemental cycling in ARD environments.
{"title":"Geochemical niches of extremophile communities in an ephemeral acid rock drainage","authors":"Mackenzie B. Best, Daniel S. Jones","doi":"10.56577/sm-2022.2865","DOIUrl":"https://doi.org/10.56577/sm-2022.2865","url":null,"abstract":"Acid rock drainage (ARD) occurs when metal sulfide minerals are exposed to surface conditions and begin to oxidize. This creates high concentrations of dissolved iron, other metals, and sulfuric acid, creating orange streams, seeps, and pools. These acidic, metal-rich sites host diverse microbial communities that includes extremophilic iron and sulfur oxidizers that take advantage of the abundant chemical energy from sulfide minerals and dissolved iron, and have adapted to extreme acidity and high metal concentrations. The Copper Flat mine is a historic copper mine located in the Hillsboro mining district in south-central New Mexico. It is a low-grade porphyry deposit where the primary copper mineralization is in the form of chalcopyrite veinlets. The mine operated at full production for 3 months in 1982, and was then placed on a care and maintenance plan to await an increase in the market price of copper, but was eventually decommissioned in the 1990s. At this site, there are two extremely acidic seeps that run only once or twice per year for no more than several weeks at a time, depending on monsoon precipitation. Year after year, a vibrant microbial community springs up when these seeps are actively running. However, we know little about the microorganisms that colonize these seeps, and how the ecology, biogeochemistry, and fate and transport of metals change during these seasonal wetting and drying cycles. Here we present preliminary data the microbial communities present in one of the seeps that was running in June 2020. pH and specific conductivity of the seep varied from 1.54-1.95 and 9.01-6.32 mS/cm, respectively. Based on rRNA gene libraries from nine exploratory samples, seep sediments were dominated by populations related to known lithotrophic iron-and sulfur-oxidizing bacteria, acidophilic organoheterotrophs, diverse algae, and novel Proteobacteria and Thermoplasmatales-group Archaea that varied with the pH and salinity gradients in the seep. Bacteria and archaea related to Leptospirillum, Acidiphilum, Acidibacter, Ferrithrix, Cuniculiplasma , and Ferrimicrobium were consistently more abundant at the more acidic site, while Acidicapsa, Acidobacterium , and Alicyclobacillus dominated at the less acidic location. We hypothesize that these differences in community composition are due to differences in pH and metal content of the waste stream, which may represent the tolerances for each population with respect to their preferred geochemical niches in these ephemeral seeps. Future work aimed at understanding the ecological and geochemical constraints on these organisms can help us to better design passive remediation strategies and understand elemental cycling in ARD environments.","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90633867","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improvement in the precision of 40 Ar/ 39 Ar sanidine geochronology has demonstrated that single crystal sanidine dates from ignimbrites are dispersed, leading to ambiguous interpretations of eruption ages. This inhibits interpretation of temporally closely spaced geologic events such as nearly coeval caldera forming eruptions, paleomagnetic reversals, extinction events, etc. Possible age dispersion sources related to (1) neutron dose differences between individual sanidine grains, (2) mineral and melt inclusion variations between grains, and (3) mass spectrometry and data reduction details have been evaluated via detailed laboratory experiments on multiple sanidine bearing ignimbrites. The accuracy of derived eruption ages is cross validated through stratigraphically constrained 27 – 28 Ma ignimbrites from the San Juan Volcanic Field that may differ in age by less than 15 ka. The 40 Ar/ 39 Ar method is based on irradiating a sample to convert 39 K to 39 Ar with the 40 Ar/ 39 Ar value being proportional to age. However, multifarious neutron flux, spatially and temporally, leads to no two grains receiving the same neutron dose, thus, variation in grain-to-grain dosage is a possible source of age dispersion. Irradiation of Fish Canyon tuff sanidine (FC-2) grains in a tightly spaced geometry significantly reduced dispersion from the typical grain-to-grain date range of up to ca. 100 ka to as low as ca. 30 ka. Although better constraining the irradiation geometry demonstrated that neutron flux variation is a large source of age dispersion, in detail, populations still show excess dispersion that likely correlates to geologic complexities. Geologic dispersion is evaluated by handpicking inclusion-free and inclusion-rich sanidine grains. Inclusion-rich grains are characterized by having visible melt and mineral inclusions when viewed under a microscope. Detailed experiments of FC-2 revealed no significant age difference or degree of dispersion
{"title":"The double-edged sword of ultra-high precision 40Ar/39Ar geochronology: Investigating previously unresolved complexities in sanidine age distributions","authors":"Tyler B. Cantrell, M. Heizler, J. Ross","doi":"10.56577/sm-2022.2859","DOIUrl":"https://doi.org/10.56577/sm-2022.2859","url":null,"abstract":"Improvement in the precision of 40 Ar/ 39 Ar sanidine geochronology has demonstrated that single crystal sanidine dates from ignimbrites are dispersed, leading to ambiguous interpretations of eruption ages. This inhibits interpretation of temporally closely spaced geologic events such as nearly coeval caldera forming eruptions, paleomagnetic reversals, extinction events, etc. Possible age dispersion sources related to (1) neutron dose differences between individual sanidine grains, (2) mineral and melt inclusion variations between grains, and (3) mass spectrometry and data reduction details have been evaluated via detailed laboratory experiments on multiple sanidine bearing ignimbrites. The accuracy of derived eruption ages is cross validated through stratigraphically constrained 27 – 28 Ma ignimbrites from the San Juan Volcanic Field that may differ in age by less than 15 ka. The 40 Ar/ 39 Ar method is based on irradiating a sample to convert 39 K to 39 Ar with the 40 Ar/ 39 Ar value being proportional to age. However, multifarious neutron flux, spatially and temporally, leads to no two grains receiving the same neutron dose, thus, variation in grain-to-grain dosage is a possible source of age dispersion. Irradiation of Fish Canyon tuff sanidine (FC-2) grains in a tightly spaced geometry significantly reduced dispersion from the typical grain-to-grain date range of up to ca. 100 ka to as low as ca. 30 ka. Although better constraining the irradiation geometry demonstrated that neutron flux variation is a large source of age dispersion, in detail, populations still show excess dispersion that likely correlates to geologic complexities. Geologic dispersion is evaluated by handpicking inclusion-free and inclusion-rich sanidine grains. Inclusion-rich grains are characterized by having visible melt and mineral inclusions when viewed under a microscope. Detailed experiments of FC-2 revealed no significant age difference or degree of dispersion","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89745678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-07DOI: 10.1130/abs/2021am-367062
G. Veni
{"title":"GEOSCIENCE OUTREACH IN THE INTERNATIONAL YEAR OF CAVES AND KARST","authors":"G. Veni","doi":"10.1130/abs/2021am-367062","DOIUrl":"https://doi.org/10.1130/abs/2021am-367062","url":null,"abstract":"","PeriodicalId":50244,"journal":{"name":"Journal of Cave and Karst Studies","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90273806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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