Statistical and geostatistical study of Rn and hydrocarbon components of a soil gas monitoring system: an application to surface hydrocarbon exploration

This work addresses three topics: (1) the study of the joint areal distribution of the Rn and hydrocarbon components of soil gases over a large region overlying some known hydrocarbon reservoirs in the southern part of Hungary; (2) the relationships between the positive anomalies of Rn and hydrocarbon components of soil gases to the existing reservoirs; (3) suggestions for new targets for surface hydrocarbon exploration based on the results. Given the very low correlation coefficients between the Rn and hydrocarbon components of the soil gases, factor analysis was used to reveal a background process controlling the common migration of hydrocarbon and Rn components. The lateral distribution of the factor scores were studied using sequential Gaussian distribution. The E-type grid generated from 100 realizations indicated several positive anomalies at the surface. Indications with a larger than 0.7 probability were kept for further analysis. Seismic sections of a 3D survey support the comparison of the surface locations of these anomalies and the surface projections of the known reservoirs. The results proved the connection between the known reservoirs and the Rn and HC components of soil gases. From the positive verification, regions with a high probability positive anomaly of factor scores, but without any reservoir counterparts may be suggested as targets for further surface hydrocarbon exploration

Climatic fluctuations inferred for the Middle and Late Pleniglacial (MIS 2) based on high-resolution (∼ca. 20 y) preliminary environmental magnetic investigation of the loess section of the Madaras brickyard (Hungary)

Abstract The Madaras brickyard section found at the northernmost fringe of the Backa loess plateau is one of the thickest and best-developed last glacial loess sequences of Central Europe. In the present work high-resolution magnetic susceptibility measurements (at 2 cm) were implemented on samples from the 10 m-section corresponding to a period between 29 and 11 KY cal b2K. One aim was to compare the findings with the ice core records of northern Greenland in order to establish a high-resolution paleoclimatic record for the last climatic cycle and with findings documented in other biotic and abiotic proxies so far. Our results revealed a strong variability of loess/paleosol formation during MIS 2. Millennial time-scale climatic events that characterize the North Atlantic during the last climatic cycle have been identified. From 29 ka up to the start of the LGM, the recorded MS values show a weak, negative correlation with the temperature proxy, and a weak positive correlation with the dust concentration of Greenland. A strong correlation was observed with the local paleotemperatures. Local climatic factors must have had a more prominent effect here on loess/paleosol development than the climate shifts over Greenland. During the LGM the same pattern is seen with a stronger correlation with the dust concentrations and a weaker correlation with the local temperature. Local climatic factors, plus dust accumulation, must have had a prominent influence on loess/paleosol development here. From the terminal part of the LGM a strong positive correlation of the MS values with the temperature proxy for Greenland accompanied by a strong negative correlation with the dust concentration values is observed. Correlation with local paleotemperatures is positive and moderate, strong. Here climate shifts over Greenland, as well as local endowments equally had an important role on the development of the MS signal