scholarly journals New data on the Dogger - Cenomanian stratigraphy of Tripolitza series in Central Crete

2018 ◽  
Vol 34 (2) ◽  
pp. 565
Author(s):  
Α. ΖΑΜΠΕΤΑΚΗ - ΛΕΚΚΑ ◽  
Α. ΑΛΕΞΟΠΟΥΛΟΣ
Keyword(s):  
Early Cretaceous ◽  
Late Eocene ◽  
Depositional Environments ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Carbonate Microfacies ◽  
Aegean Islands ◽  
Lower Aptian ◽  
Sedimentation Conditions

Tripolitza series represents the eastern part of the Gavrovo - Tripolitza platform. It outcrops in central and southeastern Peloponnesus, Crete and the Aegean islands. Its stratigraphie column starts with a volcano-sedimentary, clastic sequences (the Tyros beds), of Late Paleozoic to Late Triassic age, followed by a carbonate series of Late Triassic to Late Eocene age and a tertiary flysch. On account of intense dolomitisation as well as of rarity of fossils, the stratigraphy of Tripolitza series is not so well known as the Gavrovo series. Recent investigation attempts to complete the puzzle of Tripolitza's stratigraphie column and to reconstruct the paleogeographic sedimentation conditions. In this paper, we study some stratigraphie sections, which are taken in different places in northern – central Crete(Fig.l). New data about the stratigraphy and the sedimentation conditions of the Tripolitza series during Late Dogger to Cenomanian, complete older ones and provide information about the paleogeographic evolution of the platform. Late Dogger is determinated by Pfenderina salernitana. It is overlain by a carbonate series containing Cladocoropsis mirabilis and Macroporella sellii, dating Early Malm. Early Malm (Oxfordian - Early Kimmeridgian) is characterized by the presence of Cladocoropsis mirabilis, Kurnubia palastiniensis, Neokilianina rahonensis, Parurgonina caelinensis. Late Malm (Late Kimmeridgian - Portlandian) is characterized by Clypeina jurassica and Kurnubia palastiniensis. Early Cretaceous (Valanginian - Barremian) is determinated by Salpingoporella katzeri and Orbitolinopsis capuensis. Early Aptian is determinated by Palorbitolina lenticularis, Salpingoporella dinarica, Debarina hahounerensis, Pseudocyclammina hedbergi. Late(?) Aptian comprises Sabaudia minuta, Cuneolina hensoni, Cuneolina laurentii, Glomospira urgoniana. Albian is characterized by the disappearence of Cuneolina hensoni and Cuneolina laurentii, while Praechrysalidina infracretacea and Cretacicladus minervini are present. Late Albian is determined by the presence of "Coskinolina" bronnimanni. Early Cenomanian is not determinated by characteristic microfossils. Upper Cenomanian is overlain in comformity with upper Albian - lower Cenomanian carbonates. It is characterized by Chrysalidina gradata, Pseudorhapydionina dubia, Pseudorhapydionina laurinensis, Nummoloculina heimi, Broeckina balcanica, Nezzazata gyra, Biconcava bentori, Trochospira anvimelechi. Sedimentation took place in a peritidal environment. We observe alternations of subtidal and intratidal to supratidal conditions of sedimentation. Comparison between the carbonate microfacies of different sections representing synchronous deposits on different places of the platform, show lateral differentiation of depositional environments, from subtidal to supratidal, even supported short and local emersive episodes, (compare lower Aptian deposits of Profitis Ilias and Pinakianou sections, upper Albian deposits of Kythia and Karouzanos sections in present paper, as well as upper Cenomanian deposits of Karouzanos section in this paper, Louloudaki section (ZAMBETAKIS-LEKKAS et al. 1995 and Vitina section ZAMBETAKIS et al. 1988, Varassova section BERNIER & FLEURY 1980, Gavrovo mountain I.G.R.S. & I.F.P. 1966)(Fig.2). Similar sedimentation characterize the perimediterranean platforms during this period (SARTONI & CRESCENTI 1962, DE CASTRO 1962, FARINACCI & RADOICIC 1964, GUSIC 1969, GUSIC, NIKLER & SOKAC 1971, VELIC 1977, CHIOCCHINI et. al.1979, LUPERTO SINNI & MASSE 1993).

SIDERITE AS A CONSTRAINT ON DEPOSITIONAL AND EARLY DIAGENETIC HISTORY: EXAMPLES FROM BARROW SUB-BASIN, NORTH WEST SHELF, WESTERN AUSTRALIA

1998 ◽  
Vol 38 (1) ◽  
pp. 238 ◽  
Author(s):  
G. M. Kraishan ◽  
N. M Lemont
Keyword(s):  
Sea Level ◽  
Early Cretaceous ◽  
Meteoric Water ◽  
Sea Water ◽  
Depositional Environments ◽  
Late Triassic ◽  
Pore Waters ◽  
Sea Level Fluctuations ◽  
Isotopic Studies ◽  
Mn Content

Siderite cement is one of the most volumetrically important diagenetic minerals in the Late Triassic to Early Cretaceous sandstones of the Barrow Sub-basin. It constitutes up to 60 per cent of the rock volume, and where abundant, occludes the primary intergranular porosity. Petrogriiphic, chemical and isotopic studies indicate the early precipitation of much of this siderite prior to significant compaction. Siderite samples and concretions were taken from a variety of depositional environments ranging from fluvial to deep marine from Late Triassic to Early Cretaceous sequences.Of the early phases, three distinct siderite types were recognised and vary according to depositional environment. The first type, mostly collected from fluvial deposits, is Fe-rich with a mean composition of (Fe96.3 Mg1.8 Ca0.9 Mn1.0) C03. The second type of siderite cement is relatively Mg-rich, Ca-poor and has a higher Mn content, with a mean composition of (Fe87.1 Mg9.6 Ca1.2 Mn2.1) C03. The third type of siderite cement is typically Mg−, Ca-rich, with a low Mn content and an average composition of (Fe78.7 Mg12.4 Ca8.4 Mn0.5) C03. The second and third siderite cements occur in marine facies. The δ13C and δ180 values for siderite cements range from −2.8 to −14.3 %. PDB and 17.4 to 28.2 %. SMOW, respectively.Petrographic and chemical isotopic studies and other sedimentological data from siderite can be used to distinguish between different depositional environments. Chemical and isotopic compositions of the early authigenic siderites indicate precipitation from fluids with significant meteoric input. Siderite cements formed during sulphate reduction and early methanogenesis from mixed marine and meteoric pore-waters at temperatures below 30°C. While an influx of meteoric water to the fluvial and deltaic sediments of the Triassic Mungaroo Formation is easily envisaged, the siderites show that some mixing of sea water is also required. The concept of introduction of meteoric water to the marine sediments of the Birdrong Formation requires an appreciation of the sea level fluctuations at the time. In these situations, the recognition of meteoric or marine input to an early siderite cement can assist in the determination of sea level fluctuations.

Taxonomy and phylogeny of the Triassic bivalve families Mysidiellidae Cox, 1964 and Healeyidae new family

2008 ◽  
Vol 82 (3) ◽  
pp. 555-564 ◽  
Author(s):  
M. Hautmann
Keyword(s):  
Outer Shell ◽  
Junior Synonym ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Great Similarity ◽  
Shell Layer ◽  
Shell Microstructure ◽  
General Shape ◽  
New Family

The Mysidiellidae are morphologically isolated among Triassic bivalves but share important characters with Late Paleozoic Ambonychioidea. Apart from a great similarity in the general shape of the shell, the most primitive mysidiellid genus Promysidiella resembles ambonychioids in the presence of a duplivincular-opisthodetic ligament system. Within the Mysidiellidae, this ligament type evolved into the transitional ligament system that characterizes Late Triassic Mysidiella. The phyletic polarity indicates that this evolution probably took place by paedomorphosis. New examinations of the shell microstructure of Mysidiella demonstrate the presence of simple prismatic and possibly foliated structures in the calcitic outer shell layer, which further supports an ambonychioid affinity. Therefore, the Mysidiellidae are removed from the Mytiloidea and assigned to the Ambonychioidea. The poorly known genus Protopis, which was originally included in the Mysidiellidae, probably had a parivincular ligament system and was hence a member of the Heteroconchia. Joannina, which was previously considered a junior synonym of Protopis, is re-established. The hinge margin of Joannina carries a well developed nymph but lacks teeth. These characters as well as its modioliform shape, anterior shell lobe, and pronounced diagonal carina link Joannina with the Late Triassic genus Healeya (Modiomorphoidea). Both taxa are herein placed in the new family Healeyidae, which differs from the morphologically similar Kalenteridae in the absence of elaborated hinge teeth. Protopis, as well as the recently described genera Leidapoconcha, Waijiaoella, and Qingyaniola, are tentatively assigned to the Healeyidae.

The Tethys Himalayan passive margin from Late Triassic to Early Cretaceous (South Tibet)

1998 ◽  
Vol 16 (2-3) ◽  
pp. 173-194 ◽  
Author(s):  
Flavio Jadoul ◽  
Fabrizio Berra ◽  
Eduardo Garzanti
Keyword(s):  
Early Cretaceous ◽  
Passive Margin ◽  
Late Triassic ◽  
South Tibet

scholarly journals Coal petrology analysis and implications in depositional environments from upper Cretaceous to Miocene: a study case in the Eastern Cordillera of Colombia

2021 ◽  
Author(s):  
Clara Guatame ◽  
Marco Rincón
Keyword(s):  
Late Cretaceous ◽  
Foreland Basin ◽  
Late Eocene ◽  
Depositional Environments ◽  
Estuarine System ◽  
Eastern Cordillera ◽  
Stratigraphic Position ◽  
San Fernando ◽  
Coal Facies ◽  
Oil Sector

AbstractThe Piedemonte Llanero Basin is located on the eastern side of the Eastern Cordillera of the Colombian Andes. It has been the subject of numerous geological studies carried out for the oil sector, mainly. This study presents the coal-petrographical features of 15 coal seams of four geological formations from Late Cretaceous to Middle Miocene (Chipaque formation, Palmichal group, Arcillas del Limbo formation, and San Fernando formation). Analysis of 33 samples indicates enrichment in vitrinite, while liptinite and inertinite concentrations vary according to the stratigraphic position. Reflectance indicates that the coal range gradually decreases from highly volatile bituminous C (Chipaque formation) to subbituminous C (San Fernando formation). The microlithotypes with the highest concentrations are clarite and vitrinertoliptite. Maceral composition and coal facies indicate changes in the depositional conditions of the sequence. The precursor peat from Late Cretaceous to Late Paleocene accumulated under limnic conditions followed by telmatic in Late Eocene–Early Miocene. The coal facies indices show wet conditions in forest swamps with variations in the flooding surface, influxes of brackish water and good tissue preservation. The tectonic conditions along the Piedemonte Llanero basin is evident, from post-rift to foreland basin, evidenced by oxic and anoxic periods reflected in the maceral composition and its morphology. The coal environment corresponds to an estuarine system started in the Chipaque formation evolving to the lacustrine conditions in the San Fernando formation.

CALCITE U-Pb DATING UNRAVELS THE AGE AND HYDROTHERMAL HISTORY OF THE GIANT SHUIYINDONG CARLIN-TYPE GOLD DEPOSIT IN THE GOLDEN TRIANGLE, SOUTH CHINA

2021 ◽  
Vol 116 (6) ◽  
pp. 1253-1265
Author(s):  
Xiao-Ye Jin ◽  
Jian-Xin Zhao ◽  
Yue-Xing Feng ◽  
Albert H. Hofstra ◽  
Xiao-Dong Deng ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Early Cretaceous ◽  
South China ◽  
Gold Deposits ◽  
Ore Deposits ◽  
Late Triassic ◽  
Gold Deposition ◽  
Golden Triangle ◽  
Icp Ms ◽  
Carlin Type Gold Deposits

Abstract The ages of Carlin-type gold deposits in the Golden Triangle of South China have long been questioned due to the general lack of minerals unequivocally linked to gold deposition that can be precisely dated using conventional radiogenic isotope techniques. Recent advances in U-Pb methods show that calcite can be used to constrain the ages of hydrothermal processes, but few studies have been applied to ore deposits. Herein, we show that this approach can be used to constrain the timing of hydrothermal activity that generated and overprinted the giant Shuiyindong Carlin-type gold deposit in the Golden Triangle. Three stages of calcite (Cal-1, Cal-2, and Cal-3) have been recognized in this deposit based on crosscutting relationships, cathodoluminescence colors, and chemical (U, Pb, and rare earth element [REE]) and isotope (C, O, Sr) compositions. Cal-1 is texturally associated with ore-stage jasperoid and disseminated Au-bearing arsenian pyrite in hydrothermally altered carbonate rocks, which suggests it is synmineralization. Cal-2 fills open spaces and has a distinct orange cathodoluminescence, suggesting that it precipitated during a second fluid pulse. Cal-1 and Cal-2 have similar carbonate rock-buffered chemical and isotopic compositions. Cal-3 occurs in veins that often contain realgar and/or orpiment and are chemically (low U, Pb, and REE) and isotopically (higher δ13C, lower δ18O and Sri values) distinct from Cal-1 and Cal-2, suggesting that it formed from a third fluid. U-Pb isotope analyses, by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) for U-rich Cal-1 and Cal-2 and by LA-multicollector (MC)-ICP-MS for U-poor Cal-3, yield well-defined age constraints of 204.3 to 202.6, 191.9, and 139.3 to 137.1 Ma for Cal-1, Cal-2, and Cal-3, respectively. These new ages suggest that the Shuiyindong gold deposit formed in the late Triassic and was overprinted by hydrothermal events in the early Jurassic and early Cretaceous. Given the association of Cal-3 with orpiment and realgar, and previous geochronologic studies of several other major gold deposits in the Golden Triangle, we infer that the latest stage of calcite may be associated with an early Cretaceous regional gold metallogenic event. Combined with existing isotopic ages in the region, these new ages lead us to propose that Carlin-type gold deposits in the Golden Triangle formed during two metallogenic episodes in extensional settings, associated with the late Triassic Indochina orogeny and early Cretaceous paleo-Pacific plate subduction. This study shows that the calcite U-Pb method can be used to constrain the timing of Carlin-type gold deposits and successive hydrothermal events.

scholarly journals Age and driving mechanisms of the Eocene–Oligocene transition from astronomical tuning of a lacustrine record (Rennes Basin, France)

2021 ◽  
Vol 17 (6) ◽  
pp. 2343-2360
Author(s):  
Slah Boulila ◽  
Guillaume Dupont-Nivet ◽  
Bruno Galbrun ◽  
Hugues Bauer ◽  
Jean-Jacques Châteauneuf
Keyword(s):  
Hydrological Cycle ◽  
Sedimentary Facies ◽  
Late Eocene ◽  
Depositional Environments ◽  
Orbital Eccentricity ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Climate Conditions ◽  
Driving Mechanisms ◽  
Natural Gamma

Abstract. The Eocene–Oligocene Transition (EOT) marks the onset of the Antarctic glaciation and the switch from greenhouse to icehouse climates. However, the driving mechanisms and the precise timing of the EOT remain controversial mostly due to the lack of well-dated stratigraphic records, especially in continental environments. Here we present a cyclo-magnetostratigraphic and sedimentological study of a ∼ 7.6 Myr long lacustrine record spanning the late Eocene to the earliest Oligocene, from a drill core in the Rennes Basin (France). Cyclostratigraphic analysis of natural gamma radiation (NGR) log data yields duration estimates of Chrons C12r through C16n.1n, providing additional constraints on the Eocene timescale. Correlations between the orbital eccentricity curve and the 405 kyr tuned NGR time series indicate that 33.71 and 34.10 Ma are the most likely proposed ages of the EO boundary. Additionally, the 405 kyr tuning calibrates the most pronounced NGR cyclicity to a period of ∼1 Myr, matching the g1–g5 eccentricity term, supporting its significant expression in continental depositional environments, and hypothesizing that the paleolake level may have behaved as a low-pass filter for orbital forcing. Two prominent changes in the sedimentary facies were detected across the EOT, which are temporally equivalent to the two main climatic steps, EOT-1 and Oi-1. We suggest that these two facies changes reflect the two major Antarctic cooling/glacial phases via the hydrological cycle, as significant shifts to drier and cooler climate conditions. Finally, the interval spanning the EOT precursor glacial event through EOT-1 is remarkably dominated by obliquity. This suggests preconditioning of the major Antarctic glaciation, either from obliquity directly affecting the formation/(in)stability of the incipient Antarctic Ice Sheet (AIS), or through obliquity modulation of the North Atlantic Deep Water production.

Block tilting of the North Provence early Cretaceous carbonate margin: stratigraphic, sedimentologic and tectonic data

2009 ◽  
Vol 180 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Jean-Pierre Masse ◽  
Michel Villeneuve ◽  
Emmanuelle Leonforte ◽  
Jean Nizou
Keyword(s):  
Early Cretaceous ◽  
Biological Diversity ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Structural Elements ◽  
The North ◽  
Subaerial Exposure ◽  
Tectonic Events ◽  
Complete Series ◽  
Structural Architecture

Abstract In the western part of the Castellane tectonic arc, the so-called “ Provence platform area “, corresponding to the foreland of the Alpine nappes (figs. 1–2), is marked by Tithonian-Berriasian shallow water carbonates capped by hemipelagic sediments deposited from the Valanginian up to the Aptian-Albian. A detailed biostratigraphic study of the Berriasian succession, based on calcareous algae and foraminifera, allows us to distinguish a Lower to Middle Berriasian, with Clypeina sulcata, Clypeina isabellae and Holosporella sarda, from an Upper Berriasian with Pfenderina neocomiensis, Danubiella cernavodensis, Falsolikanella campanensis and Macroporella praturloni (fig. 3). We performed a field survey of 30 sites located from Quinson to the west, and Escragnolles to the east (figs. 4–5) including the study of measured stratigraphic sections and the collection of samples for biostratigraphic interpretations. These stratigraphic investigations show that below the Valanginian beds, the Berriasian platfom carbonate succession, is locally incomplete, i.e. Upper Berriasian beds are frequently absent. During the Early and Middle Berriasian, depositional environments are marked by a strong bathymetric instability, with frequent subaerial exposure events, and a significant marine restriction; by contrast, during the Late Berriasian, the overall biological diversity increases and water agitation as well, which means a significant marine opening towards the basin. The Upper Berriasian hiatus is consequently regarded as the result of a Berriasian/Valanginian and/or a lowermost Valanginian erosion (fig. 6). The spatial distribution of complete or truncated Berriasian successions identifies east-west bands, in each band truncated series are located northward and complete series are located southward. Bands are limited by thrust or strip faults interpreted as palaeofaults reactivated during the Alpine orogeny (fig. 7). These fault-bounded blocks, 3 to 10 km in width, known as the Aiguine, La Palud-sur-Verdon, Carajuan-Audibergue and Peyroulles-La Foux blocks, are southerly rotated by 1 to 2o. We regard this structural architecture as the result of basinward tilting of blocks. Due to their rotation, the uplifted parts were eroded whereas the depressed parts were protected against erosion (fig. 8). Such a dynamic behavior reflects a distensive tectonic regime, which has been active at least during the Valanginian, that is after the drowning of the North-Provence carbonate platform. These structural events are considered as the regional expression of the Neocimmerian tectonic phase coupled with an enhancement of the Atlantic rifting. The orientation of the major Alpine structural elements (folds and faults) of the Castellane arc, is mostly inherited from these early Cretaceous tectonic events.

The provenance of Middle Jurassic sandstones in the Scotian Basin: petrographic evidence of passive margin tectonics 1This article is one of a series of papers published in this CJES Special Issue on the theme of Mesozoic–Cenozoic geology of the Scotian Basin. 2Geological Survey of Canada Contribution 20110319.

2012 ◽  
Vol 49 (12) ◽  
pp. 1463-1477 ◽  
Author(s):  
Gang Li ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Early Cretaceous ◽  
Middle Jurassic ◽  
Mineral Chemistry ◽  
Passive Margin ◽  
Heavy Minerals ◽  
Late Triassic ◽  
Cape Breton Island ◽  
Grand Banks ◽  
Meguma Terrane ◽  
Geomorphological Evolution

The tectonic and geomorphological evolution of the Scotian margin and its hinterland is poorly known between Late Triassic rifting and the Early Cretaceous progradation of major deltas. This study determined sedimentary provenance of Middle Jurassic Mohican Formation sandstones from three wells using heavy minerals and mineral chemistry. Indicator minerals such as xenotime, altered ilmenite, and varietal types of garnet and tourmaline are similar to those in Hauterivian–Barremian sandstones in the western Scotian Basin, which are almost exclusively derived from the Meguma terrane. The wells adjacent to the Canso Ridge have more zircon and less ilmenite, indicating a greater contribution of polycyclic reworking, but with an ultimate source in the Meguma terrane. Zircon and ilmenite were likely derived in part from Carboniferous sandstones in eastern mainland Nova Scotia and Cape Breton Island. Any river drainage from the inboard terranes of the Appalachians either was diverted through the Fundy Basin or entered the easternmost Scotian Basin, where the Mohican Formation is 5.5 km thick, along the linear continuation of the southwest Grand Banks transform. Such sediment did not reach the Canso Ridge, suggesting that the Cobequid–Chedabucto fault zone in Orpheus graben was not a significant physiographic feature. This tectonically controlled paleogeography in the Middle Jurassic is quite different from that during active rifting in the Late Triassic – Early Jurassic. Middle Jurassic quiescence was followed in the Tithonian – Early Cretaceous by renewed tectonic uplift associated with rifting of Grand Banks from Iberia and Labrador from Greenland.

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