Deep-water stromatolites andFrutexites Maslov from the early and Middle Jurassic of S-Germany and Austria

Facies ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 145-168 ◽  
Author(s):  
Florian Böhm ◽  
Thomas C. Brachert
Keyword(s):  
Deep Water ◽  
Middle Jurassic

scholarly journals The provenance of Jurassic and Lower Cretaceous clastic sediments offshore southwestern Nova Scotia

2017 ◽  
Vol 54 (1) ◽  
pp. 33-51 ◽  
Author(s):  
Dan-Cezar Dutuc ◽  
Georgia Pe-Piper ◽  
David J.W. Piper
Keyword(s):  
Nova Scotia ◽  
Deep Water ◽  
Lower Cretaceous ◽  
Middle Jurassic ◽  
Sedimentary Rocks ◽  
Petroleum Exploration ◽  
Ultramafic Rocks ◽  
Meguma Terrane ◽  
Clastic Sedimentary ◽  
Fundy Basin

Jurassic and Cretaceous sandstones in the Shelburne subbasin and Fundy Basin offshore Nova Scotia, are poorly known but are of current interest for petroleum exploration. The goal of this study is to determine the provenance of sandstones and shales, which will contribute to a better understanding of regional tectonics and paleogeography in the study area. Mineral and lithic clast chemistry was determined from samples from conventional cores and cuttings from exploration wells, using scanning electron microscopy and an electron microprobe. Whole-rock geochemical composition of shales was used to test the hypotheses regarding provenance of Mesozoic clastic sedimentary rocks in the SW Scotian Basin. Lower Jurassic clastic sedimentary rocks in the Fundy Basin contain magnetite, biotite, and chlorite, suggesting local supply from the North Mountain Basalt and Meguma Terrane, whereas pyrope and anthophyllite suggest small supply from distant sources. In the SW Scotian Basin, detrital minerals, lithic clasts, and shale geochemistry from Middle Jurassic to Early Cretaceous indicate a predominant Meguma Terrane source and transport by local rivers. Rare spinel and garnet grains of meta-ultramafic rocks, only in the Middle Jurassic at the Mohawk B-93 well, suggest minor supply from the rising Labrador rift, via the same river that transported distant sediments to the Fundy Basin. Lower Cretaceous sandstones from the Mohican I-100 well contain minor garnet, spinel, and tourmaline from meta-ultramafic rocks, characteristic of sediment supplied to the central Scotian Basin at that time. The dominant Meguma Terrane provenance precludes thick deep-water sandstones in the eastern part of the Shelburne subbasin, but the evidence of Middle Jurassic distant river supply through the Fundy Basin is encouraging for deep-water reservoir quality in the western part.

scholarly journals Mesozoic sedimentary and magmatic evolution of the Arabian continental margin, northern Syria: evidence from the Baer–Bassit Melange

2002 ◽  
Vol 139 (4) ◽  
pp. 395-420 ◽  
Author(s):  
KHALIL AL-RIYAMI ◽  
ALASTAIR ROBERTSON
Keyword(s):  
Continental Margin ◽  
Deep Water ◽  
Middle Jurassic ◽  
Arabian Plate ◽  
Late Triassic ◽  
Margin Setting ◽  
Alkaline Volcanism ◽  
Thrust Sheets ◽  
Oceanic Basement ◽  
Regional Comparisons

One of the few detailed records of Mesozoic deep-water sedimentation and volcanism preserved along the tectonically emplaced Arabian continental margin is from the Baer–Bassit region of northern Syria. South-Tethyan units there occur as blocks, broken formation and disrupted thrust sheets within the Bear–Bassit Melange. Two overall composite successions are identified. The first comprises mainly sedimentary successions ranging from Late Triassic to Late Cretaceous (Cenomanian) in age. The second is dominated by Middle Jurassic–Lower Cretaceous alkaline/ per-alkaline volcanic and minor intrusive igneous rocks. The extrusives are intercalated with radiolarian sediments and capped by Cenomanian ferromanganese-rich pelagic limestone. Facies comparisons and the regional setting suggest that the Triassic to Cenomanian, mainly sedimentary units, formed in deep water near the base of the slope of the Arabian continental margin. The contrasting volcanogenic successions developed in a more distal off-margin setting. Regional comparisons (e.g. with southwestern Cyprus and southwestern Turkey) suggest that continental break-up to form a South-Tethyan oceanic basin took place in Late Triassic time, associated with alkaline volcanism. Similar alkaline volcanism of Middle Jurassic to Early Cretaceous age could reflect the activity of a mantle plume beneath the Arabian plate. Overall, sedimentation was mainly controlled by an interplay of post-rift thermal subsidence, plume-related uplift, siliceous oceanic productivity, climatic change and eustatic sea-level change. The South-Tethyan marginal to oceanic units in northern Syria were detached from an inferred oceanic basement in latest Cretaceous time, emplaced onto the Arabian continental margin, then transgressed by Maastrichian and younger autochthonous successions.

scholarly journals Ichnology of the Middle Jurassic Deposits of NE Iran: Depositional Environment Interpretation

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Mehdi Reza Poursoltani
Keyword(s):  
Deep Water ◽  
Middle Jurassic ◽  
Depositional Environment ◽  
Trace Fossil ◽  
The South ◽  
Water Turbidity ◽  
Major Break ◽  
Kopet Dagh ◽  
Northeast Iran ◽  
Ne Iran

The Kopet Dagh Basin of northeast Iran formed in the Neotethys Ocean after the closure of Paleotethys in the south of Turan plate. A thick sequence of Jurassic to Miocene sediments has been deposited in this basin without any major break. The siliciclastic Kashafrud Formation (Middle Jurassic), overlying unconformably on Triassic rocks and ultrabasic rocks of turbidite and fluvio-deltaic facies, consists of sandstone, shale and conglomerate. Trace-fossil assemblages are presented in some units with different environments. The most important ichnofossils in this formation are Skolithos, Palaeophycus tubularis, Belorhaphe, Taenidium, Planoloites beverleyensis, Thalassinoides suevicus, Conichnus, Psilonichnus, Lophoctenium, Palaeophycus striatus, Rhizocorallium jenense and Scolicia.. It is interpreted, based on identified ichnofossils, the starat may have been deposited in fluvio-deltaic and deep water (turbidity conditions) environment.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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