Search USGS⌕ Search

Geology topics

Research about Hungary

Source-linked reports with geographic coverage including Hungary.

11 recordsLinked to original sources
USGS2025

Spatial distribution and relative biomass of bigheaded carps in Lake Balaton, Hungary estimated from an environmental DNA survey

Silver carp ( Hypophthalmichthys nobilis ), bighead carp ( H. molitrix ) and their hybrids, collectively known as bigheaded carps, have been introduced to Lake Balaton, Hungary. The current stock sizes are difficult to assess. We investigated environmental DNA (eDNA) techniques targeted for bigheaded carps, assessed the spatial distribution of eDNA in Lake Balaton, compared eDNA concentrations to environmental variables to assess potential habitat selection based on those variables, and provided an estimate of biomass of bigheaded carps relative to eDNA shedding rates per unit biomass observed in controlled experiments. Water samples were collected from 70 sites in an array across the lake. Biomass estimation was calculated using mean eDNA concentration obtained by quantitative PCR of the samples and previously determined eDNA shedding rates of bigheaded carps under controlled conditions in a laboratory. Concentration of eDNA was highly variable between sites, resulting in wide confidence intervals. Basins did not significantly differ in eDNA concentration, and there were no strong relationships between environmental variables and eDNA concentration, indications that bigheaded carps use the entire lake. The model provided an estimate of 4,830 metric tonnes (2,750–8,030 tonnes) of bigheaded carps in Lake Balaton, or 81.0 kg/ha. The eDNA method produced a value close to previous estimates by traditional means of total biomass of bigheaded carps in the lake, and like traditional methods, there was a broad confidence interval on the estimate of the mean. The results of the present study support the utility of aquatic eDNA analysis, and the need for further comparisons with fisheries methods and supporting data from laboratory studies.

Lake Balaton↗
USGS2024

Themed social networking groups as effective sources of data: A country-wide survey on invasive bigheaded carp (Hipophthalmichthys molitrix and H. nobilis) detection and distribution

Citizen science commonly uses social networking platforms because they provide the easiest way to contact people. Social networking platforms can also be especially effective in that they gather people by interest and region. By sharing questionnaires and collecting photographs in angling-themed Facebook groups, we assessed the applicability of social networking groups in citizen science surveys to evaluate the distribution patterns of invasive bigheaded carp in Hungary. Altogether, we received 1,234 responses from 29 Facebook groups to four survey solicitations, with responses coming from 417 locations from across Hungary. The majority of responses were received in the first (mean ± SD; 74.3% ± 5.3) and second days (12.5% ± 5.5) after a survey questionnaire was posted. Group size was positively correlated with reach but inversely with reach ratio (reached members divided by the total number of group members). We collected 311 photos of 622 bigheaded carp, of which 470 were H. molitrix and 67 were H. nobilis . Although spatial bias occurred both in responses to survey questionnaires and available photographs, presence of bigheaded carp was confirmed in all medium and large rivers and many lentic habitats in Hungary. We demonstrated that social media groups can be used to survey interested members of the public and facilitate rapid data collection, providing an effective platform for citizen science. Repeated, spaced sharing of survey solicitations in as many groups as possible (regardless of group size) is the cornerstone for effective data collection. Our survey provided more effective and inexpensively obtained information about the distribution of bigheaded carp than standard catch-based methods.

Citizen Science: Theory and Practice↗
USGS2005

Tritium/3He dating of river infiltration: An example from the Danube in the Szigetköz area, Hungary

3 H, He, 4 He, and Ne data were obtained from a shallow ground-water system being recharged by bank infiltration from the Danube River in northwestern Hungary. After correting for excess air, 4 He and Ne concentrations reflect a recharge temperature of about 9° C., close to the mean annual temperature of the Danube (10.4° C). Values of H plus 3 Hetrit (“initial tritium”) as a function of the tritium/He age are consistent with time series measurements of tritium in the Danube. Tritium/ He ages increase linearly as a function of distance from the Danube along ground-water flow lines. A horizontal flow velocity of about 530 m yr 1 was derived from the age gradient. Most of the deviations between measured Danube tritium data and ground-water tritium/He data can be explained by dispersive mixing.

Danube River, Szigetköz area↗
USGS1996

Structure, stratigraphy, and petroleum geology of the Little Plain basin, northwestern Hungary

The basement of the Little Plain (Kisalfold) basin is composed of two parts: an eastern part comprised of folded and overthrusted Triassic and Paleozoic rocks of the Pelso block (Transdanubian Central Range) compressed in the Early Cretaceous, and a western part consisting of stacked nappes of the Austroalpine zone of Paleozoic rocks, significantly metamorphosed during Cretaceous and later compression, overriding Jurassic oceanic rift-zone rocks of the Penninic zone. The evolution of the basin began in the late Karpatian-early Badenian (middle Miocene) when the eastern part of the basin began to open along conjugate sets of northeast- and northwest-trending normal faults. Neogene rocks in the study area, on the average, contain less than 0.5 wt. % total organic carbon (TOC) and, therefore, are not considered effective source rocks. Locally, however, where TOC values are as high as 3 wt. %, significant amounts of gas may have been generated and expelled. Although potential stratigraphic traps are numerous in the Neogene section, these potential traps must be downgraded because of the small amount of hydrocarbons discovered in structural traps to date. With the exception of the Cretaceous, the Mesozoic section has not been actively explored. Large anticlinal and overthrust structures involving pre-Cretaceous strata remain undrilled.

Little Plain basin↗
USGS1994

Petroleum geochemistry of the Zala basin, Hungary

The Zala basin is a subbasin within the Pannonian basin of Hungary. Oil and smaller amounts of gas are produced from Upper Triassic through Miocene reservoirs. Our geochemical study of oils and rocks in the basin indicate that two, and possibly three, genetic oil types are present in the basin. Miocene source rocks, previously believed by explorationists to be the predominant source rock, have expelled minor amounts of hydrocarbons. The main source rock is the Upper Triassic (Rhaetian) Kossen Marl Formation or its stratigraphic equivalent. Oils derived from the Triassic source rock are recognizable by their isotopic and biological marker composition, and high content of metals. In other areas of Europe, Upper Triassic source rocks have been correlated with large oil accum lations (e.g., Molassa and Villafortuna fields, Po basin, and other fields in Italy) or are postulated to be good potential source rocks (e.g., Bristol Channel Trough). Knowledge of the geochemical characteristics of oils derived from these Upper Triassic source rocks and understanding of the source rock distribution and maturation history are important for recognizing Triassic oil-source bed relationships and for further exploration in other basins in Hungary and other parts of Europe where Triassic source rocks are present.

Zala basin↗
USGS1990

Origin and migration of hydrocarbon gases and carbon dioxide, Bekes Basin, southeastern Hungary

The Békés Basin is a sub-basin within the Pannonian Basin, containing about 7000 m of post-Cretaceous sedimentary rocks. Natural gases are produced from reservoirs (Precambrian to Tertiary in age) located on structural highs around the margins of the basin. Gas composition and stable carbon isotopic data indicate that most of the flammable gases were derived from humic kerogen contained in source rocks located in the deep basin. The depth of gas generation and vertical migration distances were estimated using quantitative source rock maturity-carbon isotope relationships for methane compared to known Neogene source rock maturity-depth relationships in the basin. These calculations indicate that as much as 3500 m of vertical migration has occured in some cases. Isotopically heavy (> − 7 > 0 ) CO 2 is the predominant species present in some shallow reservoirs located on basin-margin structural highs and has probably been derived via long-distance vertical and lateral migration from thermal decompositon of carbonate minerals in Mesozoic and older rocks in the deepest parts of the basin. A few shallow reservoirs (< 2000m) contain isotopically light (−50 to −60% 0 ) methane with only minor amounts of C 2+ homologs (< 3% v/v). This methane is probably mostly microbial in origin. Above-normal pressures, occuring at depths greater than 1800 m, are believed to be the principal driving force for lateral and vertical gas migration. These pressures are caused in part by active hydrocarbon generation, undercompaction, and thermal decomposition of carbonates.

Bekes Basin↗
USGS1987

Tectonic rotations south of the Bohemian Massif from palaeomagnetic directions of Permian red beds in Hungary

Palaeomagnetic studies were carried out in Permian red beds of the Balaton Highlands, the Mecsek Mountains and the Bükk Mountains of Hungary. Statistically well defined directions were obtained from six localities in the Balaton Highlands and two localities in the Mecsek Mountains. No meaningful results were obtained from the Bükk Mountains. Three magnetic components were identified from red beds of the Balaton Highlands: (1) in haematite with a very high unblocking temperature (700°C), interpreted as a Permian magnetization (D c = 79°, I c = -11°, k = 24, α 95 = 13.6°), in six samples from three beds in a single locality (2) a secondary but ancient component residing mainly inmaghemite (D = 314°, I = 49°, k = 48, α 95 = 10.0°), in 84 samples from six localities with a within-locality scatter increasing on unfolding; and (3) a direction parallel to the present field (D = 7°, I = 62°, k = 46, α 95 =7.7°), in nine samples from a single locality. For the Balaton Highlands, the component 1 direction agrees with directions obtained from Permian red beds and volcanics in the eastern part of the Southern and Eastern Alps and the Inner West Carpathians. All show large, apparent rotations relative to stable Europe since the Permian. Component 2 is of post-folding (post-Aptian) age. Its direction agrees with known Late Cretaceous directions from the Transdanubian Central Mountains, which also show significant counterclockwise rotation relative to stable Europe. The characteristic magnetization for the Mecsek Mountains resides in haematite and may be primary. The directions indicate only a slight net counterclockwise rotation of the Mecsek Mountains with respect to stable Europe since the Permian.

Tectonophysics↗