1,721,082 research outputs found
A graphic method for depicting basin evolution and changes in the dominant hydrodynamic process from paleocurrent data
No full textPaleocurrent data measured on depositional elements and sedimentary structures (e.g., channels, cross-strata) are commonly utilized in the description of sedimentary strata. Paleocurrent data provide information about the depositional setting and in some cases can be useful for immediately detecting specific depositional processes (e.g., herringbone cross-strata for bimodal tidal currents). The typical graphical representation used to report paleocurrent data is the rose diagram. However, rose diagrams are not able to disclose all information contained in paleocurrent data, limiting the potentiality of such a representation method. In particular, there is presently no method to highlight changes in the paleogeographic configuration that can ultimately have an impact on the evolution of depositional processes and paleocurrent direction through time. Here, we present a graphic method that permits instant visualization of anomalies in paleocurrent distributions of the stratigraphic record that can be linked to changes in the paleogeography due to tectonic evolution or in the dominant hydrodynamic process. It is important to highlight that the proposed method does not aspire to replace rose diagrams but to provide an additional tool to be used before and in combination with rose diagrams in order to extrapolate as much information as possible from paleocurrent data
Lake systems and their economic importance
No full textGeologically significant lake sequences can be found throughout the Phanerozoic rock record, and examples of lake sequences occur on all continents. Lakes that developed in large tectonic extensional or compressional basins are by far most significant, large-scale and economically important. However, the distribution of many present-day lakes is very much a reflection of Pleistocene glaciations. Within most tectonic lake basins, the main basin-filling megasequence contains three parts reflecting the early stages (initiation), climax and then late-stages (decline) of either the extension or compression that created accommodation space. Three factors of (1) subsidence versus sedimentation rate, (2) climate, and (3) hinterland geology consistently recur as key controls on sequence development, sediment composition, and facies architecture. Lake deposits record much information useful for palaeoclimatic reconstructions. Lake sequences frequently contain significant petroleum, coals and minerals, making them especially relevant to global economic development
Fieldwork and disability: An overview for an inclusive experience
No full textFieldwork forms the basis of geoscience studies. However, field activities present limitations for people with mental or physical impairments. This aspect can preclude participation in field trips by certain groups of students or limit their experience. In recent years, new types of supporting material and the development of accessible field trips have been a step forward towards the reduction of barriers to inclusion and equal opportunity. In the present work, normal practices of field teaching and potential solutions (and their limitations) to foster inclusion and accessibility to fieldwork are presented
DETECTING SHOALING-UPWARD TRENDS IN ANCIENT MIXED SILICI-/BIOCLASTIC SYSTEMS BY USING SEDIMENT SEGREGATION RATE: AN EXAMPLE FROM THE MIDDLE-UPPER PLIOCENE OF ACERENZA (LUCANIAN APENNINE OF SOUTHERN ITALY).
No full textPliocene mixed sandstones facies characteristics in the Acerenza area (Basilicata, southern Italy): implications for depositional processes and environments.
No full textShort-term periodicity tidal cycles within ancient mixed siliciclastic/bioclastic deposits: examples from Pliocene shallow-water successions of southern Apennines (Italy).
No full textSEDIMENT SEGREGATION RATE AS TOOL FOR DISCRIMINATING DEPOSITIONAL ENVIRONMENTS IN ANCIENT MIXED (SILICI-/BIOCLASTIC) SHALLOW-WATER MARINE SYSTEMS (PLIOCENE, SOUTHERN APENNINES, ITALY).
No full textAngular and tangential toeset geometry in tidal cross-strata
No full textCyclicity is one of the main characteristics used to recognise tidal current modulation in clastic deposits. Usually, cyclicity detected in cross‐strata consists of sand‐mud or siliciclastic‐bioclastic couplets, thick‐thin bundles or lateral and vertical thickness variation of rhythmites. The aim of this paper is to direct attention to the cyclicity showed by the toeset geometry, which has not been previously emphasized. Recognition of the toeset geometry can be useful in sand‐rich cross‐strata when other tidal sedimentary signals are faint or ambiguous. The lower Pleistocene cross strata of the Catanzaro Strait contain a wide suite of sedimentary structures supporting tidal origin. In particular, sand‐rich cross‐strata of the Pianopoli Unit are prone to record cyclicity in toesets geometry. Especially along the forward migration path of the bedform, toesets can be angular or tangential in shape, related to the cyclic increase and decrease of flow velocities during one tidal cycle
Regional Geology and Tectonics: Principles of Geologic Analysis Volume 1: Principles of Geologic Analysis
No full textRegional Geology and Tectonics: Principles of Geologic Analysis, 2nd edition is the first in a three-volume series covering Phanerozoic regional geology and tectonics. The new edition provides updates to the first edition’s detailed overview of geologic processes, and includes new sections on plate tectonics, petroleum systems, and new methods of geological analysis. This book provides both professionals and students with the basic principles necessary to grasp the conceptual approaches to hydrocarbon exploration in a wide variety of geological settings globally
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