Abstract The Romanian territory had a very complex geological evolution. This evolution generated a diversified geology with extended platforms limiting, to the east and south, a folded chain where spectacular overthrusts are present. More than this, posttectonic covers (basins) common to different tectonic units are also present. Some sequences of these posttectonic covers are extended from the frontal part of the folded chain over the platforms. Most of the tectonic units, as well as the post-tectonic covers, host hydrocarbon fields. On some of the tectonic units, the oil generation is proved only by the seep presence. The aim of this chapter is to briefly present the geology of the Romanian onshore, except its western part, namely, the Apuseni Mountains and the Pannonian basin. Each platform (East European, Scythian, and Moesian), each the folded chains (North Dobrudjea Orogen and groups of nappes from the East and South Carpathians [Transylvanides, Median Dacides, Outer Dacides, Marginal Dacides, Moldavides]), as well as the posttectonic basins (Transylvanian Basin, Getic Depression, Focsani Depression), have been described. For all the above-mentioned units, the standard lithostratigraphy and their internal structure are discussed. More details are given for those units that proved to be important hydrocarbon producers, namely, the Moesian Platform, Getic Depression, Subcarpathian nappe, Tarcau nappe, Diapiric fold zone, and Transylvanian Basin. The petroleum systems (including source rocks, reservoirs, and traps) of most of the units are also analyzed. From almost 1000 oil and gas fields already discovered, a reduced number of fields are quoted, just in order to give an idea on the diversity of traps. Copyright ©2006. The American Association of Petroleum Geologists. DOI:10.1306/985619M843077 The history of the geologic evolution of the Romanian onshore related to hydrocarbon genesis and accumulation conclude the chapter. Finally, it is to remark that, in spite of its character of synthesis, the chapter could be a useful tool for those scientists who are interested in an overview of Romanian geology and the related hydrocarbon fields.

Abstract After a rapid multiphase evolution and a transition from passive to active rifting during late Early Miocene to Pliocene times, the Pannonian Basin has been subjected to compressional stresses leading to gradual basin inversion during Quaternary times. Stress modelling demonstrates the significance of the interaction of external plate-boundary forces and the effect of gravitational stresses caused by continental topography and crustal thickness variation. Flexural modelling and fission-track studies have elucidated the complex interplay of flexural downloading during collision, followed by rapid unroofing by unflexing and isostatic rebound of the lithosphere. The stretching and subsidence history of the Pannonian Basin, the temporal and spatial evolution of the flexure of the Carpathian lithosphere, and the lithospheric strength of the region reflect a complex history of this segment of the Eurasia-Africa collision zone. The polyphase evolution of the Pannonian-Carpathian system has resulted in strong lateral and temporal variation in thermo-mechanical properties in the area. Modelling results suggest that, as a whole, the Pannonian Basin has been an area of pronounced lithospheric weakness since Cretaceous time, shedding light on the high degree of strain localization in this region. This basin, the hottest in continental Europe, has a lithosphere of extremely low rigidity, making it prone to multiple tectonic reactivations. Another feature is the noticeable absence of lithospheric strength in the mantle lithosphere of the Pannonian Basin. Modelling studies suggest pronounced lateral variations in lithospheric strength along the Carpathians and their foreland, which have influenced the thrust load kinematics and post-collisional tectonic history. The inferences and models discussed in this paper are constrained by a large geophysical database, including seismic profiles, gravity and heat-flow data.

Abstract The Carpathians represent the eastern extension of the European Alps (Figure 1 ), but unlike the well-known classical Alps of Western Europe, the Carpathians of Central and Eastern Europe remain less known and are even somewhat mysterious to the outside world. The tumultuous political history as well as the language barriers prevented ideas and information from flowing freely through and outside the region. However, the area greatly contributed to the common knowledge in science and technology. Enormous amounts of geological work have been conducted, and thousands of papers have been published on the geology of the Carpathian region during the past 200 yr (see references in various articles of the volume). However, because of the language barriers and diverse concepts and interpretations, it is not easy for students of Carpathian geology and potential investors to cut through all the information and to get a clear picture about the geology and the hydrocarbon potential of the region. This situation has been well known to the editors of this volume, who both worked in the Carpathians and also spent a great deal of their careers in the American petroleum industry and had a chance to see the Carpathians from the view of outside world. In the early spring of 2000, they met in Krakow, where Jan Golonka, after retiring from Mobil, had just begun his new career as a professor at the Jagiellonian University and Frank Picha, after retiring from Chevron, had completed his AAPG Distinguished Lecture tour through the countries of Eastern Europe

Abstract This review of Mediterranean geodynamics highlights that the Mediterranean region captures at a fortuitous moment in time, a picture of the fate of foundering, old, cold oceanic lithosphere of limited area due to being landlocked in an all-but-stalled continental collision (Africa with Europe). We synthesize the geological spatial and temporal data for stretched crust as well as the 3D distribution of old abyssal plains and new oceanic lithosphere segments in concert with heat flow, palaeomagnetic data, geodetic velocity data, earthquake hypocentre distributions and seismic tomography. We use three Mediterranean subduction system settings (the western Mediterranean, the Hellenic and the Pannonian–Carpathian) that nicely reflect the slab instability and retreat. We assume that mantle slab dynamics best explains the observations. The dispersal and segmentation of the foundering landlocked ocean results in a series of discontinuous subduction zones whose individual lengths gradually diminish while retreat accelerates as slab progressively narrow and tear (i.e. along-strike laterally-propagating slab break-off) due to imminent total consumption of available oceanic lithosphere. We suggest that the Mediterranean region offers a lucid series of snapshots of accelerated slab retreat that, additionally, is globally unique as the only present day example of what we term intra-collisional landlocked ocean subduction.