Transgressive-regressive Sedimentary Cycles Research Articles

The Eocene carbonate platform of the central-western Malaguides (Internal Betic Zone, S Spain) and its meaning for the Cenozoic paleogeography of the westermost Tethys

The Eocene Peñicas (Almería) and Harania (Málaga) stratigraphic sections from the Malaguide Complex (Betic Cordillera, South Spain) belonging to the Mesomediterranean Microplate from the westernmost Tethys (about-35°N and 0° to 5°E according to the Eocene coordinates) have been studied. The Eocene sections cover the Cuisian to middle Lutetian deposits, which show several lithofacies representing shallow marine platform realms. Based on the fossiliferous assemblage, texture and fabrics, eight microfacies related to inner to outer ramp settings were defined. In the inner ramp of the Harania section abundant colonial corals have been recognized. The Eocene deposits are arranged into a transgressive succession composed by three minor transgressive-regressive sedimentary cycles. The Eocene fossiliferous assemblage shows a mixture of photozoan (Larger Bentic Foraminifera –LBF–, green and red calcareous algae and corals) and heterotrophic (mollusks, echinoids, bryozoans, small benthic and planktic foraminifers) elements, suggesting euphotic to mesophotic conditions in oligo-mesotrophic marine warm-waters at low-middle latitudes. This assemblage indicates a transition from photozoan to heterozoan carbonates and in particular a shift towards outer marine ramp settings. During the Early Eocene, the widespread distribution of LBF leads in the Tethyan domains to disappearance or extreme reduction of coral constructions. Nevertheless, abundant corals associated to inner ramp realms have been observed in the Harania stratigraphic section indicating that corals could continue to develop in the westernmost Tethys at the transition to the Atlantic Ocean, in contrast with respect to other Tethyan sectors. Therefore, the Ypresian-Lutetian time-span is a transitional period for the global temperature during which corals locally survived only where optimal ecologic conditions occurred, preferably in marginal contexts, as it seems to have happened in the studied area. • Westernmost Tethys (about-30° N and 0° to 5°E according to the Eocene coordinates) • Cuisian to Middle Lutetian deposits • Shallow marine platform realms • Photozoan elements (LBF, green and red calcareous algae and corals) • Abundant corals associated to inner ramp realms

Stratigraphy and Sedimentology of Upper Cretaceous to Upper Palaeocene Succession in Zimam Formation Along Wadi Tar al Kabir, NW Libya

The Upper Cretaceous to Upper Palaeocene rocks of the Zimam Formation along the southwestern escarpment of the Hun Graben of NW Libya have been stratigraphically investigated from two stratigraphical sections in wadi Tar al Kabir. The field investigations led to the recognition of three members, from the oldest to the youngest, the Lower Tar Member, the Upper Tar Member and the Had Member. Eight sedimentary facies were distinguished at outcrop-scale and several microfacies were recognized and the outcome indicates that the depositions of the Zimam Formation are corresponding to two transgressive-regressive sedimentary cycles. The first cycle is attributed to the Lower Tar Member in which small planktonic foraminifera is quite common in the Campanian whereas the larger benthic foraminifera, namely, Omphalocyclus macroporus and Siderolites calcitrapoides are abundant in the Maastrichtian. The last occurrence of the latter two taxa, however, was used to delineate the contact between the Maastrichtian and Danian stages in the studied sequence.
 
 Up-sequence the sediments of the Upper Tar Member along with the overlying Had Member correspond to the second transgressive-regressive sedimentary cycle. Herein, the Upper Tar Member is enriched by small benthic foraminifera; Neoeponides duwi and Cibicides cf. libycus, and has been ascribed to the Danian (Lower Palaeocene). The reaming sediments of Zimam Formation, however, are belonging to the overlying Had Member and is tentatively ascribed to the Selandian (Upper Palaeocene) based on the last occurrence of the Danian fauna and the total range of the codiacean algae Ovulites morelleti.

Petrographic Assessment of Some Industrial Minerals in Selected Part of Southern Benue Trough, Nigeria

Some part of the Southern Benue Trough (Afikpo and Anambra Basins) has been mapped to determine the areas of occurrence of industrial minerals and to determine their lateral extent. The result shows that Southern Benue Trough is enriched with mostly industrial minerals of sedimentary and magmatic origin. The magmatism that occurred in the study area and its evolutionary processes led to mineralization of the study area. Interaction of the magma with host rocks gave rise to mineral genesis. The contamination and assimilation processes that occurred in the magmatic stage resulted to enrichment of minerals in the study area. The contact relationship of the magma with the host rock created a contact aureole though the resultant minerals (metamorphic minerals) of the contact aureole are not significant and exposed. The repetitive transgressive-regressive sedimentary cycle that occurred in the Southern Benue Trough probably resulted to the massive deposition of industrial minerals of sedimentary origin. The dominant and significant industrial minerals in Afikpo and Anambra Basins are sandstones (ferruginized sandstone, calcareous sandstones and carbonaceous sandstones), clay mineral (kaolinite), pebbles, igneous rocks of diverse levels of emplacement (intrusive/ extrusive), olivine , hematite, Feldspar, mica and quartz.

Are coal balls rare? A cyclostratigraphic analysis of coal-ball occurrence in North America

From the perspective of Phanerozoic time, coal balls are rare, apparently limited to a 24 m.y. interval (323–299 Ma) in the Pennsylvanian and earliest Permian. Yet within this interval, coal balls occur in many coals. Approximately 82 transgressive-regressive sedimentary cycles have been described for the Midcontinent, Illinois and Appalachian basins of North America during the mid-to-late Pennsylvanian. One third (27/82) have coal balls, including 57% of major cycles, 36% of intermediate cycles and 16% of minor cycles. Coal-ball occurrence in the Donets Basin is similar: over an interval of about 4 m.y. (~315–311 Ma, latest Bashkirian to mid-Moscovian), 39% (11/28) of transgressive-regressive cycles have coal balls. As North American paleoclimate became drier, tree ferns replaced lycopsids as the dominant plant in peat swamps at the Desmoinesian/Missourian boundary, and coal-ball occurrence declined. Overall, 47% of cycles (19/40) with lycopsid or cordaitean dominance have coal balls, whereas 19% (8/42) of cycles with tree fern dominance have coal balls (p < .004). While 32% (6/19) of minor cycles with lycopsid or cordaitean dominance have coal balls, no minor cycle with tree fern dominance has coal balls.This pattern may reflect the relative abundance of coal in the Late Pennsylvanian, with drier paleotropical climates in the Missourian-Virgilian leading to less paleotropical coal, fewer mines and a lower probability of discovering Missourian and Virgilian coal balls. However, average cycle duration decreased from 150 kyr in the Desmoinesian to ~100 kyr in the Missourian and Virgilian, and faster rates of relative sea-level rise could have affected coal-ball abundance, particularly if coal balls formed in marine swamps, with more rapid transgression leading to thinner coals, or to freshwater coals directly overlain by marine sediments. Rygel et al. (2008) suggested that Missourian-Virgilian cycles recorded more erosional relief than Desmoinesian cycles, consistent with increased amplitude and rates of sea-level rise during each glacial-eustatic cycle. Changes in Missourian-Virgilian cycles may have been augmented by stratigraphic attenuation as sediment filled the antecedent topography.

Rapid transition from the salinic to Acadian orogenic cycles in the northern Appalachian Orogen: Evidence from northern New Brunswick, Canada

Geochronological data from volcanic rocks aid in reconstructing the Silurian–Devonian evolution of the northern Appalachians of New Brunswick in the context of Salinic (Silurian) and Acadian (Devonian) orogenesis. Late Silurian to Early Devonian sedimentation, volcanism and deformation in northern New Brunswick is complex, and characterized by transgressive-regressive sedimentary cycles, local disconformities and angular unconformities, and two stages (ca. 422–419 Ma, and ca. 417–407 Ma) of typically bimodal, within-plate magmatism. These events overlapped the end of the Salinic orogenic cycle, related to the ca. 430 Ma collision of the Ganderian passive margin with composite Laurentia, and the beginning of the Acadian cycle, which is associated with subsequent (ca. 424–422 Ma) collision and underthrusting of Avalonian crust beneath composite Laurentia (now including the Gander margin). Following Ganderia−Laurentia collision, the earlier (Pridolian) stage of within-plate magmatism is interpreted to result from ca. 425 Ma detachment of the subducting Tetagouche backarc lithospheric slab and is linked to the Salinic cycle, along with local, pre-Acadian (Salinic C) deformation of Ludlow−Pridoli rocks. Break-off of the Tetagouche slab also led to rapid uplift and subsequent extensional collapse of the Salinic metamorphic core, resulting in latest Silurian-earliest Devonian D3 vertical shortening and flat belt formation in the Brunswick subduction complex. Precise ID-TIMS U-Pb (zircon) dating of volcanic rocks reveals the existence of a 2.2 myr hiatus in the stratigraphic record, corresponding to an interpreted latest Silurian–earliest Devonian erosional surface between volcanic rocks identified with the Salinic cycle (Dickie Cove Group and lower part of Tobique Group) and those associated with the Acadian cycle (Dalhousie Group). The disconformity coincides with a widespread marine regression recorded by roughly coeval deposition of shallow-water to intertidal redbeds across the northern Appalachians. Marine regression is closely followed by deposition of Lochkovian deep marine sedimentary rocks (turbidites) in the Seboomook foredeep. This regressive-transgressive sequence immediately precedes arrival of the northwest-migrating Acadian deformation front, and is interpreted as evidence of a migrating Acadian forebulge-foredeep system associated with flexural loading of Ganderian crust by the Acadian orogenic wedge situated farther southeast in southern New Brunswick and coastal Maine. Early Devonian volcanism and Acadian retro-arc foreland deformation are linked to flat-slab convergence of Avalonia after underthrusting of buoyant Avalonian continental crust began ca. 418 Ma. It is proposed that the latest Silurian−earliest Devonian disconformity and marine regression mark the beginning of the Acadian orogenic cycle, implying that, in northern New Brunswick, the effects of waning, late Silurian (Salinic) deformation temporally overlapped the early, far-field effects of Acadian orogenesis.

Geodynamic Significance of Stacking Lower Cambrian Sequences Units in the Western Anti-Atlas

In the Anti-Atlas the lower Cambrian succession was traditionally considered as a post-rift series. Recently the Western Anti-Atlas appears to be affected by an early Cambrian rifting process. In the Igherm area (Western Anti-Atlas), this succession is represented by an alternating carbonate and siliciclastic facies reflecting several sedimentary environments. The vertical stacking of these facies define four Composite-Sequences constituted, each one, by two or more transgressive-regressive sedimentary cycles. The differential and progressive extensional tectonic events seem to be the main control on the genesis and on the vertical stacking transgressive-regressive sedimentary cycles. The accommodation space is generated by a strong tilting related to syn-rift tectonics. The lack of lowstand system tracts and other erosive features, suggests the occurrence of platform drowning just below the falling sea level stage. So stratigraphic stacking of the Lower-Cambrian strata exposed in the Igherm area, constitutes the response to the rifting process in the Anti-Atlas and consequently a probably fragmentation indicator of a neoproterozoic Gondwana.

Middle-Upper Miocene paleogeography of southern Turkey: insights from stratigraphy and calcareous nannofossil biochronology of the Olukpınar and Başyayla sections (Mut-Ermenek Basin)

The age of the marine succession capping the basement rocks of the central Taurides in the Mut-Ermenek Basin is constrained using calcareous nannofossil biochronology. The Olukpinar section, which correlates with the biozones between MNN5a and MNN6b (late Langhian-late Serravallian), represents a deeper marine environment developed lateral to the Ermenek platform. The long-term transgressive-regressive cycle of the Olukpinar section, which corresponds to the middle-upper part of the TB2 supercycle, can be subdivided into 2 large-scale (106 years) cycles (TB2.4 and TB2.5) based on the occurrence of 2 major debris flow deposits linked to sea-level drop. The younger late Tortonian Basyayla section represents a transgressive-regressive sedimentary cycle (TB3.2 cycle) responsible for the major transgressive event that occurred at the southern margin of the Central Anatolian Plateau during the Late Miocene. This major transgressive event is responsible for the migration of the coastal onlap of the Mediterranean Sea towards the interior of the Anatolian Peninsula, almost 100 km inland from the present Eastern Mediterranean coast line. The ~8 Ma age of the younger marine sediments deposited during the TB3.2 cycle, which onlap the basement rocks of the central Taurides at an elevation of ~2 km, represents a maximum age for the start of surface uplift of the Central Anatolian Plateau's southern margin.

Discovery of Versilian deposits suitable for beach nourishment on the continental shelf of Western Liguria

In this paper we present the results of a study conducted in collaboration with the Ligurian Region, in the framework of the E.U. Beachmed-e Interreg IIIc Project, to distinguish relic coastal deposits on the continental shelf, suitable for beach nourishment. These deposits are related to transgressive-regressive sedimentary cycles, and they are due to Quaternary glacio-eustatic sea level variations. In fact, during the sea level low stand associated with the last glacial maximum (c.18–20,000 yBP) the sea level was 110–120 m lower than its present level and the continental shelf was exposed. During the Versilian Transgression the coastline migrated from the shelf break to its present position. This migration was not continuous and conspicuous sediment bodies, associated with deltaic or littoral systems, were deposited during static periods. The results of a marine geology campaign with seismostratigraphic and sedimentological analyses enabled us to distinguish gravelly and sandy littoral deposits at depths of 20–40 m near the coast and 60–80 m on the outer shelf, in areas with only a thin Holocene mud cover (high stand deposits).

Environmental changes and diversification ofCyprideis in the Late Miocene of the Styrian Basin (Lake Pannon, Austria)

The turnover from the Sarmatian Paratethys Sea into Lake Pannon around 11.6 Ma seriously impacted aquatic biota like ostracods and triggered their adaptation to the changed environments. One survivor of this ecological switch is certainly the genusCyprideis, which is well known for its radiation in Lake Pannon. A high-resolution micropalaeontological investigation of a transgressive-regressive sedimentary cycle just above the Middle/Late Miocene boundary focused on the taxonomy of the foundCyprideis species. Species-diagnostic characters were evaluated applying qualitative as well as lineal and geometric morphometric analyses. These examinations led to the introduction of two new ostracod species (Cyprideis kapfensteinensisGross n. sp. andCyprideis mataschensisGross n. sp.), which diverge only indistinctly in outline, but are undoubtedly separated by their size and hinge structure along with considerable differences in number of posteroventral spines. We conclude that these co-occurring species were two sympatric species, which were probably adapted to different microhabitats.C. kapfensteinensis is only recognised in the interval at the peak of the transgression, which corresponds to the maximum deepening of the lake in this area and with meso-/polyhaline conditions. In contrast,C. mataschensis seems to be a more euryplastic species because it appears well before this event and is also recorded in the regressive prodelta sediments up section.

Environmental and biotic changes across the Permian–Triassic boundary in western Tethys: The Bulla parastratotype, Italy

The sedimentary and biotic evolution of a 190 m interval of shallow marine and lagoonal facies in the Bellerophon and Werfen formations in the Southern Alps has allowed comparison of western with eastern Tethys: Meishan D section (southern China), Salt Range (Pakistan) and Abadeh (Iran). Results are as follows: (1) The upper part of the Bellerophon Fm. (Changhsingian changxingensis–deflecta Zone) shows only modest biotic variation connected with tectonically driven local variation and perhaps to more general climatic variation. The δ 13C decrease starting in the uppermost 30 m of the Bellerophon Fm. is correlated with decrease in global organic productivity starting about 1 m below the PTB in Chinese sequences and 20 m below in the Abadeh section. This interval culminated in a regression truncated by an unconformity–paraconformity (Unconformity 1). (2) The uppermost Bellerophon Fm. is a ca. 1 m transgressive-regressive sedimentary cycle, the informally named Bulla Mbr (Changhsingian: Early praeparvus Zone). The maximum flooding interval of this unit possibly had a slight increase in biodiversity, mainly in foraminifers, algae and brachiopods. The high increase in biodiversity previously reported may, in part, reflect abundance of biota and organic matter reworked into transgressive and regressive intervals. We suggest partial correlation of the basal unconformity of the Bulla Mbr (Unconformity 1) with the regressive uppermost Bed 24e of the Meishan D section marking the disappearance of foraminifers and algae in the eastern Tethys. We also suggest diachronous disappearance of benthic taxa in Tethys, with the Southern Alps acting like a refugium. (3) The main extinction (first extinction phase, mainly regarding foraminifers) in the Southern Alps occurred in a thin ca. 25 cm interval including the uppermost regressive Bulla Mbr, Unconformity 2, and possibly, the basal transgressive bed of the Tesero Mbr of the Werfen Fm. This interval is correlated in part with regressive Bed 26 of Meishan D section. The main decrease in abundance and biodiversity in the Southern Alps coincides with appearance of small oolites with crystalline outer cortex near the basal transgressive tract of the lower Tesero Mbr, a ca. 220 cm sedimentary cycle, that is followed by extension of microbialitic layers alternating with veritable biostromes with brachiopods and byssate bivalves as salient components among the algae. Vacated niches favored evolution of conodonts. Hindeodid conodont biodiversity increased with species developing characteristics of Isarcicella. This interval has been referred to the Changhsingian Late praeparvus Zone and correlated with Bed 27a–b of Meishan D section. The PTB has been identified in the Bulla section at 1.30 m from the base of the Werfen Fm. – with the first appearance of Hindeodus parvus defining the base of the parvus Zone – in a microbialitic layer correlated with Bed 27c of Meishan D section. Around the PTB the major part of the remaining Permian biota disappeared. Gymnocodiacean algae were the last group to undergo extinction within the Triassic layers. (4) Biodiversity dropped severely in the succeeding bioturbated microbialitic interval from which conodonts are absent. More humid climate is reflected in a more sandy marine substrate inhabited by Lingula, Unionites and Claraia. Conodonts recurred in the schizohaline upper part. The succeeding entry of the biozonal markers Isarcicella lobata, Isarcicella staeschei and Isarcicella isarcica allow discrimination of three conodont biozones. The layer with entry of I. staeschei has been aligned with Bed 28 of Meishan D section. The main extinction phase in the western Tethys seems to correspond to a gradual but swift transition from acid-bath to alkaline-bath according to the Deev Jahi model of Heydari and Hassanzadeh [Heydari, E. and Hassanzadeh, J., 2003. Deev Jahi model of the Permian–Triassic boundary mass extinction: a case for gas hydrates as the main cause of biological crisis on Earth. Sed. Geol., 163, 147–163.]. The Bulla section with abundant data on biotic and depositional variation is here considered as the PTB parastratotype for the shallow marine western Tethys.

Marine and Transitional Middle/Upper Eocene Units of the Southeastern Pyrenean Foreland Basin (NE Spain)

The stratigraphic basis of this work has allowed the use of larger foraminifers in the biostratigraphic characterisation of the new Shallow Benthic Zones (SBZ). This part of the volume presents a description of the sedimentary cycles formed by the transgressive-regressive systems of the Lutetian and Bartonian in the southeastern sector of the Ebro Foreland Basin.Concerning the Lutetian deposits studied in the Amer-Vic and Emporda areas, four sedimentary cycles have been characterised. The first and second are found within the Tavertet/Girona Limestone Formation (Reguant,1967;Palli,1972), while the third and fourth cycles cover the Coll de Malla Marl Formation (Clavell et al.,1970), the Bracons Formation (Gich,1969,1972), the Banyoles Marl Formation (Almela and Rios,1943),and the Bellmunt Formation (Gich,1969,1972). In the Bartonian deposits studied in the Igualada area,two transgressive-regressive sedimentary cycles have been characterised in the Collbas Formation (Ferrer,1971),the Igualada Formation (Ferrer,1971),and the Tossa Formation (Ferrer,1971). The Shallow Benthic Zones (SBZs)recognised within the Lutetian are the following:SBZ 13, from the Early Lutetian, in the transgressive system of the first cycle;SBZ 14,from the Middle Lutetian, in the second cycle and the lower part of the transgressive system of the third cycle; SBZ 15,from the Middle Lutetian, in the remaining parts of the third system; SBZ 16, from the Late Lutetian,throughout the fourth cycle.The association of larger foraminifers in the first and second cycles of the Bartonian in the Igualada area has been used as the basis for the definition of SBZs 17 and 18 recognised in the Bartonian of the western Tethys.

Caractérisation et interprétation de cycles géochimiques sur la plate-forme bourguignonne (France) au Bajocien-Bathonien

A sedimentological and facies sequence study, coupled with geochemical analyses (Sr, Mg, Fe, Mn and δ 18O) was made on a core (Ravières, Yonne; south-east Paris Basin, France) in the Bajocian-Bathonian carbonate-shelf sedimentary succession. By studying the strontium variations, geochemical cycles can be correlated to transgressive-regressive sedimentary cycles. However, the interpretation of the geochemical cycles must refer to a different standard than the studies generally realised in basin environments.

Middle Tertiary Sedimentary Regimen of Gulf Coastal Region

The middle Tertiary sedimentary regimen of the Gulf Coast is related directly to Rocky Mountain events, and most of the terrigenous sediments came from the Rocky Mountains. A relatively minor amount of terrigenous material was derived from Mid-Continent, Appalachian, and Piedmont sources, and from Mesozoic rocks in the Gulf coastal region. Carbonate rocks and bioclastic rocks in the eastern Gulf region are autochthonous or were derived locally. Criteria are given for identifying transgressive and regressive trends in both surface exposures and subsurface sections. Juvenile (freshly arrived) clastic materials are winnowed in transport to coastal areas during the early part of transgressive phases. Sand with small quantities of reworked gravel is the first juvenile material deposited in the marine environment. Gravel arrives later and tongues out downdip above the basal sand. Clay and bioclastic material are deposited downdip at the same time that juvenile sand is deposited updip. Lag in transport causes both juvenile sand and gravel to transect time lines upward downdip. The sedimentation cycle is related to the normal inverse relation between sea-level and stream gradient. Periods of non-deposition in the marine environment (diastems) that have been attributed to oscillation of sea-level, but which do not correspond to regressive maximums, are attributed to unknown and undeterminable lapses in sediment transport, to submarine scouring, and to tectonic activity. Disconformities are classified as eustatic or tectonic; either type may coincide with subaerial erosion. Major events in geologic history can be deciphered by recognition of these disconformities and with consideration of the terrigenous-carbonate (or bioclastic) ratio in sediments, the aggrading or degrading behavior of streams, and the transgressive-regressive sedimentary cycle. Correlation between the surface and the subsurface is based on equation with transgressive and regressive phases. Gulf coastal stages are delimited by regressive maximums. Transgressive and regressive trends are believed to have been gradual or irregular, not oscillatory as is commonly supposed. The outer-shelf shale tongues which usually are identified by distinctive foraminiferal assemblages, such as the Hackberry, Abbeville, and Harang assemblages, are regarded as regressive maximums, not transgressions as frequently stated. The Textularia warreni tongue of the subsurface Vicksburg and the Anahuac tongue represent transgressive peaks. Pure bentonite, as found in strata of the Vicksburg Group, provides the only means of direct correlation with middle Tertiary Rocky Mountain events. Pyroclastic and terrigenous debris, which required fluvial transportation to the Gulf, is delayed one stage as a result of the transgressive-regressive sedimentary cycle. Difficulty in locating the Oligocene-Miocene boundary around the world results from the fact that the Aquitanian Stage is defined as a time-stratigraphic unit based on a type section (stratotype) by some authors and as a biostratigraphic unit by other authors. The base of the stratotype section is at about the middle of the biostratigraphic unit. Some European authors recently have regarded Chattian-Aquitanian as a single stage, thus agreeing with the inclusion of both in one transgressive-regressive cycle.