Early Cretaceous stratigraphy, depositional environments, sandstone provenance, and tectonic setting of central Tibet, western China

2004 ◽  
Vol 116 (9) ◽  
pp. 1202 ◽  
Author(s):  
Kai-Jun Zhang ◽  
Bang-Dong Xia ◽  
Guan-Min Wang ◽  
Yong-Tie Li ◽  
He-Fei Ye
2018 ◽  
Vol 161 ◽  
pp. 74-92 ◽  
Author(s):  
Xia-Nan Zhang ◽  
Guang-Ming Li ◽  
Ke-Zhang Qin ◽  
Bernd Lehmann ◽  
Jin-Xiang Li ◽  
...  

2021 ◽  

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.


2018 ◽  
Vol 34 (2) ◽  
pp. 565
Author(s):  
Α. ΖΑΜΠΕΤΑΚΗ - ΛΕΚΚΑ ◽  
Α. ΑΛΕΞΟΠΟΥΛΟΣ

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).


2009 ◽  
Vol 180 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Jean-Pierre Masse ◽  
Michel Villeneuve ◽  
Emmanuelle Leonforte ◽  
Jean Nizou

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.


2019 ◽  
Vol 7 (2) ◽  
pp. T525-T545
Author(s):  
Yaxiong Sun ◽  
Wenlong Ding ◽  
Yang Gu ◽  
Gang Zhao ◽  
Siyu Shi ◽  
...  

Redbeds with a large thickness in the lower Cretaceous record abundant geologic information in the Minle Basin. We have conducted the paleoweathering conditions, provenance, and tectonic settings based on mineralogy and geochemistry. Our results indicate that mudstone samples are characterized by abundant illite with negligible amounts of K-feldspars and analcime. The lower part of the lower Cretaceous is rich in quartz, whereas the upper part is dominated by dolomite and analcime. We suggest that this is caused by the decreasing input of the clastic influx during the middle-late early Cretaceous. High index of compositional variation values (average 1.33) indicate first-cycle sediment supply, suggesting an overall compositional immaturity and short-distance transportation. These characteristics are consistent with an active regional extension tectonic setting. The [Formula: see text] system ([Formula: see text];[Formula: see text];[Formula: see text]) and Th/U versus Th consistently reveal that the lower Cretaceous experienced a positive gradient in chemical weathering from young to old formations. Although the patterns of trace elements in three formations of the lower Cretaceous are different, those of the rare earth elements (REEs) tend to be consistent. The significant enrichment of light REEs, heavy REEs fractionation, and distinctive negative Eu anomalies suggest derivation from an old, upper continental crust composed of predominantly felsic sediments. This interpretation is supported by several discrimination diagrams such as titanium dioxide-nickel ([Formula: see text]), which shows the characteristics of immature recycled sediments. A few sensitive elements, ratios, and normalized REE patterns indicate a provenance of an active continental margin and a continental island arc (CIA). The La-Th-Sc, Th-Co-Zr/10, and Th-Sc-Zr/10 discrimination plots further confirm the CIA signature. Thus, we conclude that the early Cretaceous redbeds in the Minle Basin, Hexi Corridor, were deposited in a dustpan-shaped half-graben basin in a CIA setting when northwest China was influenced by intense regional extension.


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