Geological Heritage, Geotourism and Local Development in Aggtelek National Park (NE Hungary)

We examine how geoconservation and geotourism can help the local development of an economically underdeveloped karst area. First, we briefly present the geoheritage of Aggtelek National Park, which largely overlaps the area of the Aggtelek Karst. The area is built up predominantly of Triassic limestones and dolomites. It is a typical temperate zone, medium mountain karst area with doline-dotted karst plateaus and tectonic-fluvial valleys. Besides caves, the past history of iron mining also enriches its geoheritage. Aggtelek National Park was set aside in 1985. The caves of Aggtelek Karst and Slovak Karst became part of the UNESCO World Heritage in 1995 due to the high diversity of cave types and morphology. Socially, the area of the national park is a disadvantaged border region in NE Hungary. Baradla Cave has always been a popular tourist destination, but visitor numbers fell significantly after 1985. Tourism is largely focused on Baradla Cave, and thus it can be considered “sensu lato” geotourism. Reasons for the changes in visitor numbers are discussed in this paper. Tourist motivations, the significance of geotourism and other tourism-related issues were explored in our study by questionnaire surveys and semi-structured interviews. Furthermore, the balance of geoconservation versus bioconservation is also examined. Finally, the relationship of geotourism, nature protection and local development is discussed. We conclude that the socio-economic situation of the Aggtelek Karst microregion is relatively better than that of the neighbouring regions, and this relative welfare is due to the existence of the national park and Baradla Cave

Eruptive history of the Late Quaternary Ciomadul (Csomád) volcano, East Carpathians, part II: magma output rates

This study, which builds on high-precision unspiked Cassignol-Gillot K-Ar age determinations, presents an advanced DEMbased volumetrical analysis to infer long-term magma output rates for the Late Quaternary Ciomadul (Csomád) dacitic lava dome complex (East Carpathians, Romania). The volcanic field of Ciomadul developed on the erosional surface of Lower Cretaceous flysch and ~ 2 Ma old andesites and experienced an extended eruptive history from ~ 850 to < 30 ka. Predominantly effusive activity took place during the first stage (~ 850 to ~ 440 ka), producing volumetrically minor, isolated, peripheral domes. Subsequently, after a ~ 250 ky repose interval, a voluminous central dome cluster developed in the second stage (~ 200 to < 30 ka). During the youngest phase of evolution (~ 60 to < 30 ka), highly explosive eruptions also occurred, resulting in the formation of two craters (Mohos and St. Ana). The calculated ~ 8.00 ± 0.55 km3 total volume of the lava domes, which includes the related volcaniclastic (1.57 km3 ) as well as erosionally removed (0.18 km3 ) material, is in line with dimensions of other medium-sized dacitic lava domes worldwide. This volume was extruded at an average long-term magma output rate of 9.76 km3 / My (0.0098 km3 /ky). However, most of the domes (7.53 ± 0.51 km3 ) were formed in the 200 to < 30 ka period, implying a significantly increased magma output rate of 37.40 km3 /My (0.0374 km3 /ky), more than 30 times higher than in the first stage. Within these long-term trends, individual lava domes of Ciomadul (e.g. those with volumes between 0.02 and 0.40 km3 ) would have been emplaced at much higher rates over a period of years to tens of years. The active periods, lasting up to hundreds of years, would have been followed by repose periods ~ 30 times longer. The most recent eruption of Ciomadul has been dated here at 27.7 ± 1.4 ka. This age, which is in agreement with radiocarbon dates for the onset of lake sediment accumulation in St. Ana crater, dates fragmented lava blocks which are possibly related to a disrupted dome. This suggests that during the last, typically explosive, phase of Ciomadul, lava dome extrusion was still ongoing. In a global context, the analysis of the volumetric dynamism of Ciomadul’s activity gives insights into the temporal variations in magma output; at lava domes, short-term (dayor week-scale) eruption rates smooth out in long-term (millenia-scale) output rates which are tens of times lower

Clinically relevant mutations in the ABCG2 transporter uncovered by genetic analysis linked to erythrocyte membrane protein expression

The ABCG2 membrane protein is a key xeno- and endobiotic transporter, modulating the absorption and metabolism of pharmacological agents and causing multidrug resistance in cancer. ABCG2 is also involved in uric acid elimination and its impaired function is causative in gout. Analysis of ABCG2 expression in the erythrocyte membranes of healthy volunteers and gout patients showed an enrichment of lower expression levels in the patients. By genetic screening based on protein expression, we found a relatively frequent, novel ABCG2 mutation (ABCG2-M71V), which, according to cellular expression studies, causes reduced protein expression, although with preserved transporter capability. Molecular dynamics simulations indicated a stumbled dynamics of the mutant protein, while ABCG2-M71V expression in vitro could be corrected by therapeutically relevant small molecules. These results suggest that personalized medicine should consider this newly discovered ABCG2 mutation, and genetic analysis linked to protein expression provides a new tool to uncover clinically important mutations in membrane proteins. © 2018 The Author(s)

Drainage development, neotectonics and base-level change in the Kalahari Desert, southern Africa

The Kalahari Desert contains extensive networks of ephemeral and fossil drainage which are potential indicators of past and present neotectonic activity and climatedriven environmental change. An absence of topographic data has hindered our understanding of their development. We present long-profile information for twentynine valley networks derived from Shuttle Radar Topographic Mission (SRTM) digital elevation data. In total, 8354 km of valley talweg was measured for x, y and z information. Most valleys exhibit concave-up profiles. Fifty-five previously unknown knickpoints were identified. The majority coincide with lithological boundaries or fractures, but many developed in response to Neogene uplift and/or downwarping or occur where valleys cross palaeolake shorelines. The headwaters of four valleys cross the Kalahari–Limpopo drainage divide and predate the presumed Miocene uplift of the Kalahari–Zimbabwe axis, suggesting that they are of considerable antiquity

Towards reconstruction of the lost Late Bronze Age intra-caldera island of Santorini, Greece

During the Late Bronze Age, the island of Santorini had a semi-closed caldera harbour inherited from the 22 ka Cape Riva Plinian eruption, and a central island referred to as &apos;Pre-Kameni&apos; after the present-day Kameni Islands. Here, the size and age of the intracaldera island prior to the Late Bronze Age (Minoan) eruption are constrained using a photo-statistical method, complemented by granulometry and high-precision K-Ar dating. Furthermore, the topography of Late Bronze Age Santorini is reconstructed by creating a new digital elevation model (DEM). Pre-Kameni and other parts of Santorini were destroyed during the 3.6 ka Minoan eruption, and their fragments were incorporated as lithic clasts in the Minoan pyroclastic deposits. Photo-statistical analysis and granulometry of these lithics, differentiated by lithology, constrain the volume of Pre-Kameni to 2.2-2.5 km3. Applying the Cassignol-Gillot K-Ar dating technique to the most characteristic black glassy andesite lithics, we propose that the island started to grow at 20.2 ± 1.0 ka soon after the Cape Riva eruption. This implies a minimum long-term lava extrusion rate of ~0.13-0.14 km3/ky during the growth of Pre-Kameni. © 2018 The Author(s)

Constraining the landscape of Late Bronze Age Santorini prior to the Minoan eruption: Insights from volcanological, geomorphological and archaeological findings

One of the best known places on Earth where volcanology meets archaeology and history is the volcanic island of Santorini (Thíra), Greece. It is famous for the cataclysmic Late Bronze Age (Minoan) Plinian eruption which destroyed the Minoan culture that flourished on the island. Hosting a central, flooded caldera bay and, within that, the active islands of Palaea and Nea Kameni, Santorini volcano has been the focus of international research efforts for over one and a half centuries. In this paper, we summarize recent findings and related ideas about the Minoan physiography of the island, also known as Strongyli, from a volcanological, geomorphological and archaeological point of view. As proposed as early as the 1980s, a central caldera bay existed prior to the Late Bronze Age. Probably characterised by a smaller size and located in the northern part of the present-day caldera, this earlier caldera bay was formed during the previous Plinian eruption – called Cape Riva eruption – c. 22,000 years ago. Within the caldera bay, a central island, Pre-Kameni, existed, named after the present-day Kameni Islands. High-precision radioisotopic dating revealed that Pre-Kameni started to grow c. 20,000 years ago. Whereas volcanologists have accepted and refined the caldera concept, archaeologists have generally favoured the theory of an exploded central cone instead of a pre-existing central caldera. However, analysis of the Flotilla Fresco, one of the wall paintings found in the Bronze Age settlement of Akrotiri, reveals the interior of a Late Bronze Age caldera that may be interpreted as a realistic landscape. Approximately 3600 years ago, the island of Strongyli was destroyed during the explosive VEI = 7 Minoan eruption. Pre-Kameni was lost by this eruption, but its scattered fragments, together with other parts of Strongyli, can be recovered as lithic clasts from the Minoan tuffs. On the basis of photo-statistics and granulometry of the lithic clasts contained in the Minoan tuffs, complemented by volumetric assessment of the erupted tephra and digital elevation model (DEM) analysis of alternative models for the pre-eruptive topography, the volume of Pre-Kameni can be constrained between 1.6 and 3.0 km3, whereas the volume of the destroyed portion of the ring island of Strongyli between 9.1 and 17.1 km3. Of these, the larger values are considered more realistic, and imply that most of the destroyed part of Strongyli was incorporated as lithic components in the Minoan tuffs, whereas up to 3 km3 of Strongyli might have been downfaulted and sunken during caldera formation and is not accounted for in the lithics. © 2020 The Author