Abstract. Permeability is one of the most important petrophysical parameters to describe the reservoir properties of sedimentary rocks, pertaining to problems in hydrology, geothermics, and hydrocarbon reservoir analysis. Outcrop analogue studies, well core measurements, and individual sample analysis take advantage of a variety of commercially available devices for permeability measurements. Very often, permeability data derived from different devices need to be merged within one study (e.g. outcrop minipermeametry and lab-based core plug measurements). To enhance accuracy of different gas-driven permeability measurements, devicespecific aberrations need to be taken into account. The application of simple one-to-one correlations may draw the wrong picture of permeability trends. For this purpose, transform equations need to be established.This study presents a detailed comparison of permeability data derived from a selection of commonly used Hassler cells and probe permeameters. As a result of individual crossplots, typical aberrations and transform equations are elaborated, which enable corrections for the specific permeameters. Permeability measurements of the commercially available ErgoTech gas permeameter and the TinyPerm II probe permeameter are well-comparable over the entire range of permeability, with R 2 = 0.955. Aberrations are mostly identified in the permeability range < 10 mD, regarding the TinyPerm II and the minipermeameter/Hassler-cell combination at Darmstadt University, which need to be corrected and standardized. Applying standardizations which consider these aberration intervals strongly improves the comparability of permeability data sets and facilitates the combination of measurement principles. Therefore, the utilization of such correlation tests is highly recommended for all kinds of reservoir studies using integrated permeability databases.

This review paper summarizes the sedimentary and palaeoenvironmental evolution of the Junggar Basin in Northwest China largely based on hardly accessible Chinese language papers, and complemented by own field observations and a critical survey of key sediment cores from petroleum wells. We have combined this information and updated existing lithofacies and isopach maps for characteristic time slices of basin evolution and palaeoenvironmental change. The Junggar Basin was initiated during the late stage of collisional tectonics in the southern Central Asian Orogenic Belt (Altaids) since the Early Permian. According to studies in surrounding mountain chains and geophysical surveys, the basement consists of a collage of oceanic basins, intraoceanic island arcs, and microcontinents of Precambrian to Palaeozoic age. The basin fill is subdivided into three tectonically controlled stratigraphic sequences which are separated by two regional angular unconformities. The first cycle in the Permian and Triassic is characterized by an Early Permian extensional strike-slip and a Late Permian to Triassic compressional foreland setting. After an Early Permian marine regression, persistent nonmarine fluvio-lacustrine conditions were established containing probably the thickest organic-rich mudstone interval in the world, which act as major source rocks of the basin. Starting with four depocenters, the basin was unified during the Triassic. The preserved total maximum thickness of this cycle is about 8,500 m in the southern depocenter. During the second intracontinental depression cycle, subsidence slowed down and the depocenter migrated towards the basin center reaching a maximum thickness of 6,000 m. The palaeoenvironment was dominated by a large oscillating freshwater lake receiving changing quantities of clastic sediments from the surrounding mountain ranges and forming alluvial fans, braid plains, and deltas partly containing coal seams of economic interest. Sedimentary facies, pollen, and palaeobotanical plant fossils show an overall aridization trend and a shrinking lake cover. During the Neogene cycle, the depocenter migrated back to the south and the former asymmetric foreland basin was reactivated due to thrusting and rapid uplift of the Tian Shan. The maximum thickness of these molasse-type deposits exceeds 5,000 m. Despite its strong potential, there is still a lack of high resolution bio-and cyclostratigraphy, sequence stratigraphy, and palaeoclimate studies in the Junggar Basin to elucidate local versus regional palaeoenvironmental patterns and to better constrain fardistance tectonic forcing.

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This study presents an almost complete Middle Miocene to Pleistocene sequence of synrift sediments in the western branch of the East African Rift. The studied succession is exposed in several patches on an eastward tilted block between the northern tip of the Rwenzori Block and the eastern shoulder of the Albert Rift. In this position, it reaches a maximum thickness of 600 m of which 350 m have been logged systematically by analysing lithofacies and sediment architecture. Stratigraphic subdivision of the succession relies on published biostratigraphic data of endemic mollusc associations and their correlation across East Africa. The synrift sediments encountered are siliciclastics ranging from clay to coarse gravel with gypsum and ferrugineous interlayers or impregnations. Lithofacies and architectural analysis indicate alluvial plain, delta plain, nearshore, delta front, or lacustrine depositional environments. Based on the vertical stacking pattern, prograding and retrograding trends of the depositional environments, and climatic indicators (e.g. conservation of feldspar, gypsum, and/or iron hydroxide precipitation), four evolutionary phases can be distinguished: (i) a first phase between ca. 14.5 and 10.0 Ma is characterised by bedload-dominated fluvial environment with massive sandy to gravelly bedforms, feldspar-rich sands, rare iron impregnations and relatively low accommodation space. This phase is interpreted as pre-and early synrift sedimentation under a semiarid climate. (ii) From ca. 10.0 to 4.5 Ma predominantly fine-grained siliciclastics were deposited in a distal fluvial plain to lacustrine setting characterised by limited accommodation space. Fluctuation of thin beds, dominance of clay and frequent iron impregnations point to a more humid climate with seasonality and weak tectonic activity. (iii) During the third phase between 4.5 and 2.0 Ma delta plain and nearshore deposits with frequent ferrugineous impregnations and rich mollusc associations occurred, indicating a humid period with lake-level highstands and accelerated subsidence. (iv) During the final sedimentary interval between 2.0 and 1.5 Ma gravel units reoccurred with less iron-but more carbonate and gypsum impregnations, and arkosic sandstones. This phase recorded a general aridisation trend most probably caused by the upcoming rain barrier of the Rwenzori Mountains together with accelerated rift-flank uplift and strong subsidence of the rift floor. The results of this study are of particular importance for delineating key controls on sedimentation in the Albert Rift.

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Alluvial fans serve as useful archives that record the history of depositional and erosional processes in mountainous regions and thus can reveal the environmental controls that influenced their development. Economically, they play an important role as groundwater reservoirs as well as host rocks for hydrocarbons in deeply buried systems. The interpretation of these archives and the evaluation of their reservoir architecture, however, are problematic because marked heterogeneity in the distribution of sedimentary facies makes correlation difficult. This problem is compounded because the accumulated sedimentary deposits of modern unconsolidated fan systems tend to be poorly exposed and few such systems have been the focus of investigation using high-resolution subsurface analytical techniques. To overcome this limitation of standard outcrop-analogue studies, a geophysical survey of an alpine alluvial fan was performed using ground-penetrating radar to devise a scaled three-dimensional subsurface model. Radar facies were classified and calibrated to lithofacies within a fan system that provided outcropping walls and these were used to derive a three-dimensional model of the sedimentary architecture and identify evolutionary fan stages. The Illgraben fan in the Swiss Alps was selected as a case study and a network of ca 60 km sections of ground-penetrating radar was surveyed. Seven radar facies types could be distinguished, which were grouped into debris-flow deposits and stream-flow deposits. Assemblages of these radar facies types show three depositional units, which are separated by continuous, fan-wide reflectors; they were interpreted as palaeo-surfaces corresponding to episodes of sediment starvation that affected the entire fan. An overall upward decline in the proportion of debris-flow deposits from ca 50% to 15% and a corresponding increase in stream-flow deposits were identified. The uppermost depositional unit is bounded at its base by a significant incision surface up to 700 m wide, which was subsequently filled up mostly by stream-flow deposits. The pronounced palaeo-surfaces and depositional trends suggest that allocyclic controls governed the evolution of the Illgraben fan, making this fan a valuable archive from which to reconstruct past sediment fluxes and environmental change in the Alps. The results of the integrated outcrop-geophysical approach encourage similar future studies on fans to retrieve their depositional history as well as their potential reservoir properties.

The volcaniclastic Tepoztlán Formation (TF) represents an important rock record to unravel the early evolution of the Transmexican Volcanic Belt (TMVB). Here, a depositional model together with a chronostratigraphy of this Formation is presented, based on detailed field observations together with new geochronological, paleomagnetic, and petrological data. The TF consists predominantly of deposits from pyroclastic density currents and extensive epiclastic products such as tuffaceous sandstones, conglomerates and breccias, originating from fluvial and mass flow processes, respectively. Within these sediments fall deposits and lavas are sparsely intercalated. The clastic material is almost exclusively of volcanic origin, ranging in composition from andesite to rhyolite. Thick gravity-driven deposits and largescale alluvial fan environments document the buildup of steep volcanic edifices. K-Ar and Ar-Ar dates, in addition to eight magnetostratigraphic sections and lithological correlations served to construct a chronostratigraphy for the entire Tepoztlán Formation. Correlation of the 577 m composite magnetostratigraphic section with the Cande and Kent (1995) Geomagnetic Polarity Time Scale (GPTS) suggests that this section represents the time intervall 22.8-18.8 Ma (6Bn.1n-5Er; Aquitanian-Burdigalian, Lower Miocene). This correlation implies a deposition of the TF predating the extensive effusive activity in the TMVB at 12 Ma and is therefore interpreted to represent its initial phase with predominantly explosive activity. Additionally, three subdivisions of the TF were established, according to the dominant mode of deposition: (1) the fluvial dominated Malinalco Member (22.8-22.2 Ma), (2) the volcanic dominated San Andrés Member (22.2-21.3 Ma) and (3) the mass flow dominated Tepozteco Member (21.3-18.8 Ma).

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