Jan Golonka

Paleoreef maps; evaluation of a comprehensive database on Phanerozoic reefs

To get a better understanding of controls on reef development through time, we created a comprehensive database on Phanerozoic reefs. The database currently comprises 2470 reefs and contains information about geographic position/paleoposition, age, reef type, dimensions, environmental setting, paleontological and petrographical features, and reservoir quality of each buildup. Reef data were analyzed in two qualitatively different ways. The first type of analysis was by visualization of paleogeographic reef distribution maps. Five examples (Late Devonian, Early Permian, Late Triassic, Late Jurassic, middle Miocene) are presented to show the potential of paleoreef maps for paleogeographic and paleoclimatological reconstructions. The second type of analysis was a numerical processing of coded reef characteristics to realize major trends in reef evolution and properties of reef carbonates. The analysis of paleolatitudinal reef distributions through time shows pronounced asymmetries in some time slices, probably related to climatic asymmetries rather than controlled by plate tectonic evolution alone. The dominance of particular reef builders through time suggests that there are seven cycles of Phanerozoic reef development. First curves for the Phanerozoic distribution of bioerosion in reefs, bathymetric setting, and debris potential of reefs are presented. The observed pattern in the temporal and spatial distribution of reefs with reservoir quality may assist in hydrocarbon exploration. Statistical tests on the dependencies of reefal reservoir quality suggest that large size, high debris potential, low paleolatitude, high amount of marine aragonite cement, and a platform/shelf edge setting favor reservoir quality. Reefal reservoirs are significantly enhanced in times of high evaporite sedimentation, elevated burial of organic carbon, low oceanic crust production, low atmospheric CO2 content, and cool paleoclimate, as well as when they are present in aragonite oceans.

Patterns of Phanerozoic carbonate platform sedimentation

Carbonate platforms changed substantially in spatial extent, geometry, composition and palaeogeographical distribution through the Phanerozoic. Although reef construction and carbonate platform development are intimately linked today, this was not the case for most of the Phanerozoic. Carbonate production by non-enzymatic precipitation and non-reefal organisms is mostly responsible for this decoupling. Non-reefal carbonate production was especially prolific during times of depressed reef growth, balancing losses in reef carbonate production. Palaeogeographical distribution and spatial extent of Phanerozoic carbonate platforms exhibit trends related to continental drift, evolutionary patterns within carbonate platform biotas, climatic change and, possibly, variations in ocean chemistry. Continental drift moved large Palaeozoic tropical shelf areas into higher latitudes, thereby reducing the potential size of tropical platforms. However, the combined global size of carbonate platforms shows no significant decline through the Phanerozoic, suggesting that availability of tropical shelf areas was not a major control of platform area. This is explained by the limited platform coverage of low-latitude shelves (42% maximum) and occasional high-latitude excursions of platform carbonates. We speculate that reduced tropical shelf area in the icehouse tropics forced the migration of the many carbonate-secreting organisms into higher latitudes and, where terrigenous input was sufficiently low, extensive carbonate platform could develop.

Plate-tectonic Evolution and Paleogeography of the Circum-Carpathian Region

Sixteen time interval maps were constructed that depict the latest Precambrian to Neogene plate-tectonic configuration, paleogeography, and lithofacies of the circum-Carpathian area. The plate-tectonic model used was based on PLATES and PALEOMAP software. The supercontinent Pannotia was assembled during the latest Precambrian as a result of the Pan-African and Cadomian orogenies. All Precambrian terranes in the circum-Carpathian realm belonged to the supercontinent Pannotia, which, during the latest Precambrian–earliest Cambrian, was divided into Gondwana, Laurentia, and Baltica. The split of Gondwana during the Paleozoic caused the origin of the Avalonian and then Gothic terranes. The subsequent collision of these terranes with Baltica was expressed in the Caledonian and Hercynian orogenies. The terrane collision was followed by the collision between Gondwana and the amalgamation of Baltica and Laurentia known as Laurussia. The basement of most of the plates, which was an important factor in the Mesozoic–Cenozoic evolution of the circum-Carpathian area, was formed during the late Paleozoic collisional events. The older Cadomian and Caledonian basement elements experienced Hercynian tectonothermal overprint. The Mesozoic rifting events resulted in the origin of oceanic-type basins like Meliata and Pieniny along the northern margin of the Tethys. The separation of Eurasia from Gondwana resulted in the formation of the Ligurian–Penninic–Pieniny Ocean as a continuation of the Central Atlantic Ocean and as part of the Pangean breakup tectonic system. During the Late Jurassic–Early Cretaceous, the Outer Carpathian rift developed. The latest Cretaceous–earliest Paleocene was the time of the closure of the Pieniny Ocean. The Adria–Alcapa terranes continued their northward movement during the Eocene–early Miocene. Their oblique collision with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and foreland basin. The northward movement of the Alpine segment of the Carpathian–Alpine orogen has been stopped because of the collision with the Bohemian Massif. At the same time, the extruded Carpatho-Pannonian units were pushed to the open space toward the bay of weak crust filled up by the Outer Carpathian flysch sediments. The separation of the Carpatho-Pannonian segment from the Alpine one and its propagation to the north were related to the development of the north–south dextral strike-slip faults. The formation of the Western Carpathian thrusts was completed by the Miocene. The thrust front was still progressing eastward in the Eastern Carpathians. The Carpathian loop, including the Pieniny Klippen structure, was formed. The Neogene evolution of the Carpathians resulted also in the formation of the genetically different sedimentary basins. The various basins were formed because of the lithospheric extension, flexure, and strike-slip-related processes.

Phanerozoic paleogeography, paleoenvironment and lithofacies maps of the circum-Atlantic margins

Abstract A series of maps was constructed, depicting the plate tectonic configuration, paleogeography, paleoenvironment and lithofacies for Phanerozoic time intervals from Cambrian through the Neogene. These are world maps comprising 300 continental plates and terranes, but are reprojected here to illustrate the circum-Atlantic margins. The relative position of the continents through time was largely derived from PLATES and PALEOMAP software. These maps illustrate the Phanerozoic geodynamic evolution of the Earth. They show the relationship of the continental configuration, lithofacies, tectonics, and climate, from the time of the disassembly of Rodinia to the assembly and break-up of Pangea. From a regional perspective, the facies in basins along the circum-Atlantic margin reflect various stages of rifting and passive margin development. Inversion caused by ridge push played an important role in the basin evolution and has influenced the distribution of lithofacies at various times. The power of the maps is realized in their application as an aid to the visualization of the relationship of regional basin development, sedimentation and erosion to the deposition of potential source-rock, reservoir and seals. The individual maps illustrate the conditions present during the maximum marine transgressions of sea-level within the Sauk, Tippecanoe, Kaskaskia, Absaroka, Zuni, and Tejas megasequences of Sloss. Relative sea level cyclicity, chronostratigraphy, and regional unconformities provide the basis for partitioning these higher frequency depositional cycles into 32 subdivisions (supersequences) ranging in duration from 11 to 39 my. In this report 14 of these time slices are used to illustrate the environments and lithologies resulting from changes in the geographic position of the terranes which constitute the present Atlantic margins. The text attempts to fill in details of the progressive change between mapped intervals. Data for the maps were derived from geologic reports, maps and stratigraphic columns and other paleogeographic interpretations regarding tectonics, basin formation, and deposition. The lithofacies are depicted by 21 patterns.

The Carpathians and their foreland: geology and hydrocarbon resources

This volume of 30 chapters authored by 107 geologists and geophysicists from Austria, Czech Republic, Hungary, Poland, Romania, Slovakia, Ukraine, United Kingdom, and the USA provides a comprehensive and understandable account of geology and hydrocarbon resources of the entire Carpathian system from northeastern Austria to southern Romania, including the Neogene foredeep, the foreland platform both in front and beneath the thrust belt, the Carpathian thrust belt, and the late and post orogenic intermontane basins. Principal chapters on regional geology are supplemented by thematic contributions on geodynamic reconstructions, regional geophysical investigations, hydrocarbon systems, and case studies of major oil and gas fields. To date, close to 7 billion barrels of oil and more than 53 trillion cubic feet of natural gas have been produced from the entire Carpathian system. Additional new reserves may be found, especially at deeper structural levels below the Neogene foredeep and the thin-skinned Carpathian thrust belt. Seventeen chapters of Memoir 84 have been printed in full. The remaining chapters have been printed as abstracts only, with the full paper for all 30 chapters as .pdf files on the CD-ROM in the back of this publication. The publication is intended as a source of information to schools, governmental and private institutions, oil companies, and potential investors.

Paleogeographic reconstructions and basins development of the Arctic

Abstract Paleogeographic maps were constructed to depict the Phanerozoic plate tectonic configuration, paleoenvironment and lithofacies. These maps illustrate the geodynamic evolution of the circum-Arctic region. The relationship of the continental configuration, lithofacies, tectonics and climate from the disassembly of Rodinia to the assembly and breakup of Pangea is clearly depicted on this series of reconstructions. The distribution of lithofacies shows climatic change associated with continental assembly and disassembly as well as with the steady northward drift of the continents. From a regional perspective the facies in basins along the circum-Arctic margin reflect various stages of geotectonic development. The assembly of continents contributed to the formation of foreland basins. The breakup of continents, especially of the Pangean supercontinent, generated basins related to rifting and passive margin development. The subduction zones are related to the back-arc basins. The inversion caused by ridge pushing played an important role in the basin evolution.

Geodynamic evolution and palaeogeography of the Polish Carpathians and adjacent areas during Neo-Cimmerian and preceding events (latest Triassic-earliest cretaceous)

Abstract The aim of this paper is to place the geodynamic and palaeogeographical evolution and position of the major crustal elements of the Polish Carpathians within a global framework. Neo-Cimmerian movements and their synsedimentary consequences are the main objects of our elaboration in relation to sedimentary record. Five time-interval maps are presented, which depict the plate-tectonic configuration, palaeogeography and lithofacies for the circum-Carpathian region and adjacent areas from the Late Triassic through to the Early Cretaceous. Almost simultaneous tectonic events proceeding within different types of Carpathian sedimentary basins (Pieniny Klippen Belt and Outer Carpathian Silesian Basins) indicate the very important role of the Neo-Cimmerian movements (mainly of the Osterwald Phase) in the geodynamic history of the northernmost margin of the Tethyan Ocean. The global plate reorganization is related to this Tethyan Neo-Cimmerian tectonic activity.

Geology and Hydrocarbon Resources of the Outer Carpathians, Poland, Slovakia, and Ukraine: General Geology

The purpose of this chapter is to provide the general overview of the stratigraphy and tectonics of the Polish, Ukrainian, and adjacent parts of the Slovakian Outer Carpathians. The Polish and Ukrainian Outer Carpathians form the north and northeastern part of the Carpathians that expand from the Olza River on the Polish–Czech border to the Ukrainian–Romanian border. Traditionally, the Northern Carpathians are subdivided into an older range, known as the Inner Carpathians, and the younger ones, known as the Outer Carpathians. These ranges are separated by a narrow, strongly tectonized belt, the Pieniny Klippen Belt. The Outer Carpathians are made up of a stack of nappes and thrust sheets showing a different lithostratigraphy and tectonic structures. Generally, each Outer Carpathian nappe represented separate or partly separate sedimentary subbasin. In these subbasins, enormous continuous sequence of flysch-type sediments was deposited; their thickness locally exceeds 6 km (3.7 mi). The sedimentation spanned between the Late Jurassic and early Miocene. During the folding and overthrusting, sedimentary sequences were uprooted, and generally, only sediments from the central parts of basins are preserved. The Outer Carpathian nappes are overthrust on each other and on the North European platform and its Miocene–Paleocene cover. In the western part, overthrust plane is relatively flat and becomes more and more steep eastward. Boreholes and seismic data indicate a minimal distance of the overthrust of 60–80 km (37–50 mi). The evolution of the Northern Outer Carpathian Flysch basins shows several tectonostratigraphic stages. The first period (Early Jurassic–Kimmeridgian) began from the incipient stage of rifting and formation of local basins. The next stage (Tithonian–Early Cretaceous) is characterized by rapid subsidence of local basins where calcareous flysch sedimentation started. The third period (Late Cretaceous–early Miocene) is characterized by compression movements, appearance of intensive turbiditic sedimentation, and increased rate of subsidence in the basins.

Hot spot activity and the break-up of Pangea

Abstract The Mesozoic and Cenozoic positions of the continents that formed Pangea in the Triassic–Jurassic were derived from paleomagnetic and intraplate volcanic data, paleoclimatic observations, such as reef and fossil flora distribution, and geological observations. Major hot spots helped to determine the longitudinal position of Pangea and to construct a model of plate motion during the Pangean break-up. The position of the northern part of Pangea was constrained using Iceland and Jan Mayen hot spots. The Iceland hot spot was traced from its present day position to Greenland in the Paleocene, to Baffin Bay in the Late Cretaceous, to the Alpha Ridge in the Early Cretaceous, to the Chukchi Borderland in the Middle–Late Jurassic, to Franz Joseph Land in the Early Jurassic, the Yenisei–Khatanga Trough in the Middle Triassic, and finally to West Siberia in the Late Permian–Early Triassic. The hot spot activity is expressed by Eastern and Western Greenland volcanics, the Siberian trap basalts, and perhaps by Alpha Ridge and Chukchi Borderland volcanics. The Chukchi Borderland volcanics are related to the early stage of the opening of the Canadian Basin. The position of the southern part of Pangea was constrained using the Bouvet hot spot. This hot spot was tracked from its present day position to Western Antarctica in the Early Cretaceous–Late Jurassic and to South Africa in the Early Jurassic–Late Triassic. This hot spot activity produced the Ferrar and Karoo volcanics. The model of plate motion obtained agrees with other data on intraplate volcanics, which are also related to hot spots. At the time of the opening of the Central Atlantic, the Cape Verde and Canary Island hot spots were located along the oceans spreading axis. The long lasting location of hot spot and associated mantle upwelling plumes could help to explain forces driving the Tethys transit plates, opening of the Ligurian Ocean and Eastern Mediterranean. The European hot spots are related to the several Mesozoic phases of rifting. For example, the Rhine Graben hot spot may have been located at the rifting axis in the North Sea. Several authors have already discussed the contribution of hot spots to the opening of the South Atlantic and Indian oceans. Mantle plumes associated with hot spots play an active role in rifting and initial phases of spreading. The lithospheric displacement, caused by upwelling combined with sometimes remote collisional forces on the other side of continental plate, may result in compression and basin inversion.

Fluctuations in the carbonate production of Phanerozoic reefs

Abstract A comprehensive database on Phanerozoic reefs is used to evaluate the carbonate production of reefs through time. Net, gross and export carbonate productions of 2760 Phanerozoic reefs are calculated and the cumulative production for 32 time slices is evaluated. The total amount of carbonate produced in the reef ecosystem in a given time slice is a function of global reef abundance, average reef size and the relative amount of carbonate exported from the reefs. Carbonate production of reefs is usually low, but characterized by prominent peaks in the mid-Silurian Givetian-Frasnian, the Late Triassic, the Late Jurassic, the mid-Cretaceous and the Neogene. The determinants of reefal carbonate production are correlated with a variety of intrinsic and extrinsic parameters such as palaeogeographic setting, dominant biota, reef type, bioerosion, petrographic composition, eustatic sea level, oceanic crust production rates, atmospheric CO2 concentrations, and global nutrient level. The calculated carbonate production, however, is rarely correlated with particular Earth system parameters. This implies that either the controls on reefal carbonate production are too complex to allow reliable predictions, or biotic factors represent more important controls than physico-chemical parameters. The constructed curve of Phanerozoic reefal carbonate export production is also poorly correlated with proposed curves of global shallow-water carbonate production suggesting that reefs rarely contributed in a quantitatively significant way to the global carbonate budget.