Stratigraphy and depositional setting of the Lagrelius Point Formation from the Lower Cretaceous of James Ross Island, Antarctica

1993 ◽  
Vol 5 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Luis A. Buatois ◽  
Francisco J. Medina
Keyword(s):  
Sedimentary Facies ◽  
High Density ◽  
Coarse Grained ◽  
Turbidity Currents ◽  
North West ◽  
The North ◽  
Braided Channel ◽  
James Ross Island ◽  
Siliciclastic Rocks ◽  
Sandstone Facies

The Lagrelius Point Formation (?Barremian–Aptian) is the basal unit of the Gustav Group and crops out on the north-west coast of James Ross Island. It consists of about 250 m of coarse-grained siliciclastic rocks. The type section of the Lagrelius Point Formation is defined here from just south of Lagrelius Point. The measured section comprises the uppermost 80 m of the unit and mainly consists of clast-supported, boulder, cobble to pebble conglomerates; very coarse to medium-grained sandstones occur rarely. Four sedimentary facies are recognized. A disorganized conglomerate facies (1) is interpreted as having been deposited from non-cohesive debris flows and high density gravelly turbidity currents. Inversely graded conglomerate facies (2) and normally graded to graded stratified conglomerate and pebbly sandstone facies (3) reflect sedimentation from high density gravelly turbidity currents. Massive and parallel stratified sandstone facies (4) is thought to record deposition from high density sandy turbidity currents. Two types of facies assemblages have been recognized. A major channel assemblage, represented by the lower part of the measured section and the minor channel assemblage forming the upper part of the section. The total succession is thought to represent the aggradation of a major submarine braided channel followed by the establishment and subsequent infill of a series of minor channels in a marginal terrace.

Paleogeography of the Matapédia basin in the Gaspé Appalachians: initiation of the Gaspé Belt successor basin

2004 ◽  
Vol 41 (5) ◽  
pp. 553-570 ◽  
Author(s):  
Michel Malo
Keyword(s):  
Carbonate Platform ◽  
Source Area ◽  
Turbidity Currents ◽  
Northern Limit ◽  
Fine Grained ◽  
The North ◽  
Iapetus Ocean ◽  
Thrust Sheets ◽  
Siliciclastic Rocks ◽  
Lime Muds

The Matapédia basin consists of the uppermost Ordovician – lowermost Silurian deep-water, fine-grained carbonate–siliciclastic rocks of the Honorat (Garin Formation) and Matapédia groups (Pabos and White Head formations), the lower rock assemblage of the Gaspé Belt in the Gaspé Appalachians. Paleogeographic maps of eight time slices from the Caradocian to the Llandoverian are presented to better understand the tectonosedimentary evolution of the Matapédia basin. Deposition evolved from siliciclastic (Garin Fm.) to argillaceous limestones (Pabos Fm.), to limestones (White Head Fm.). The overall change from terrigenous (Garin Fm.) to limestone facies (White Head Fm.) reflects a change in the source area. Paleocurrent directions and composition of sandstones indicate an orogenic source area to the south for the Garin Formation, which is believed to be the inliers of the Humber and Dunnage zones in the southern Gaspé and New Brunswick Appalachians. Lime muds deposited by turbidity currents coming from the north suggest the Anticosti active carbonate platform as the source area for the White Head Formation. The Matapédia basin was filled from south to north. First deposits, the Garin Formation, occurred south of the Taconian thrust sheets (Humber Zone) and also south of the Grenville basement. This region was the domain of the Ordovician Iapetus Ocean (Dunnage Zone). The northern limit of the basin migrated northward during deposition of the Matapédia Group in Ashgillian–Llandoverian times and reached its actual northern limit at the very end of the Llandoverian (C6), when siliciclastic facies of the lower Chaleurs Group were deposited.

scholarly journals Sedimentation of deep-water turbidites in the SW part of the Pannonian Basin

2010 ◽  
Vol 61 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Boris Vrbanac ◽  
Josipa Velić ◽  
Tomislav Malvić
Keyword(s):  
Deep Water ◽  
Pannonian Basin ◽  
Eastern Alps ◽  
Turbidity Currents ◽  
Main Stream ◽  
North West ◽  
Fine Grained ◽  
The North ◽  
Sandstone Body ◽  
West Part

Sedimentation of deep-water turbidites in the SW part of the Pannonian BasinThe Sava Depression and the Bjelovar Subdepression belong to the SW margin of the Pannonian Basin System, which was part of the Central Paratethys during the Pannonian period. Upper Pannonian deposits of the Ivanic-Grad Formation in the Sava Depression include several lithostratigraphic members such as Iva and Okoli Sandstone Member or their lateral equivalents, the Zagreb Member and Lipovac Marlstone Member. Their total thickness in the deepest part of the Sava Depression reaches up to 800 meters, while it is 100-200 meters in the margins of the depression. Deposits in the depression are composed of 4 facies. In the period of turbiditic activities these facies are primarily sedimented as different sandstone bodies. In the Bjelovar Subdepression, two lithostratigraphic members (lateral equivalent) were analysed, the Zagreb Member and Okoli Sandstone Member. The thickness of the Bjelovar Subdepression ranges from 50 meters along the S and SE margins to more than 350 meters along the E margin. Generally, detritus in the north-west part of the analysed area originated from a single source, the Eastern Alps, as demonstrated by sedimentological and physical properties, the geometry of the sandstone body and the fossil content. This clastic material was found to be dispersed throughout the elongated and relatively narrow Sava Depression and in the smaller Bjelovar Subdepression. Sedimentation primarily occurred in up to 200 meters water depth and was strongly influenced by the sub-aqueous paleorelief, which determined the direction of the flow of turbidity currents and sandstone body geometries. The main stream with medium- and fine-grained material was separated by two independent turbiditic flows from N-NW to the SE-E. Variability in the thickness of sandstone bodies is the result of differences in subsidence and cycles of progradation and retrogradation of turbidite fans.

scholarly journals Siwalik basin of Arunachal Himalaya, India: a case study

1998 ◽  
Vol 18 ◽  
Author(s):  
P. K. Das ◽  
H. Baruah
Keyword(s):  
Sedimentary Facies ◽  
Western Himalaya ◽  
Large River ◽  
Ocean Basin ◽  
North West ◽  
The North ◽  
Late Neogene ◽  
Main Boundary Fault ◽  
Uplift And Erosion ◽  
Arunachal Himalaya

The Siwalik basin of Arunachal Himalaya is a part of the Himalayan foreland. Due to continental collision between Indian and Eurasian plates, the Himalayan mountain system experienced intense uplift and erosion and as a result, a large amount of siliciclastic sediments accumulated within the foreland and a remnant ocean basin (which was commonly known as foredeep) was developed during Eocene. Moreover, the sediments were deposited by a large river draining the uplifted Himalayan belt during late Neogene. From the pattern of lithofacies, the river may be envisaged as braided type and was a bit shallow relative to its width, floored by bars and channels of low sinuosity and with a bed load of sand and pebbly sediments. These sediments present in the Arunachal foothills are bounded by the Brahmaputra Alluviums in the south and the Gondwana belt in the north and, by a system of frontal faults and the Main Boundary Fault, respectively. The sediments are mostly of molasse type (Upper Tertiary sediments), of different sedimentary facies present in the form of thick accumulation of multilateral and multistoried bodies. Moreover, the depositional basin suffered from some tectonic disturbances for which open folds and many reverse faults were formed. With the formation of foredeep infront of the Himalaya, a reversal of slope towards north-west took place in post-Barail times and during the later part of the Tertiary, the Himalayan and the Upper Assam basin were continuous below the Brahmaputra Alluviums as evidenced by field and laboratory observations. From these observations, it is seen that the Siwalik basin of Arunachal Himalaya has close resemblance with the Tertiary basin (Neogene basin) of Upper Assam rather than the Siwalik basin of western Himalaya and thus, this basin may be treated as a separate basin which may be renamed as "Tertiary basin of Arunachsl".

Rembang Zone Petroleum Play, Stratigraphic and Petrographic Analysis of Ngrayong Formation as Reservoir, Jamprong Area, Tuban, East Java

2020 ◽  
Author(s):  
D., S. Reka
Keyword(s):  
Depositional Environment ◽  
Carbonate Platform ◽  
Research Area ◽  
Geological Mapping ◽  
Coarse Grained ◽  
Petrographic Analysis ◽  
North East ◽  
The North ◽  
Potential Reservoir ◽  
Sandstone Facies

The following research took place in the Jamprong area, Tuban Regency, East Java Province within a study area of 2 km2. Physiographically, the study area is situated in the anticlinorium of the Rembang Zone. This research aims to define the reservoir potential of outcrop samples from the Ngrayong Formation as an analogue for the subsurface. In addition, the depositional environment and the age of the rock in the research area was determined. The Ngrayong Formation is regarded as a potential reservoir in the North East Java Basin. The accumulated data consists of stratigraphy, petrographic analysisand paleontological analysis of rock samples, and geological mapping has been carried out to determine the distribution of rocks. Facies were determined based on outcrop observations and comprise predominantly arkose sandstone facies with fine – coarse grained, moderately sorted and with cross-bedding, herringbone, and lamination, and another facies namely massive carbonate grainstone. Based on these facies, the interpreted depositional environment is the transition of tidal flat to shallow marine carbonate platform with relative biostratigraphic age of Middle Miocene, Langhian to Serravallian (M6-M8 planktonic foraminiferal biozones). Rocks in the study area have porosity >20% or very good and permeability >130 or fair based on petrographic observations, and this supports the interpretation of the Ngrayong Formations as a potential reservoir of hydrocarbons.

New Evidence Concerning the Original Order of Deposition of the Longmyndian Rocks

1948 ◽  
Vol 85 (2) ◽  
pp. 107-109 ◽  
Author(s):  
John Challinor
Keyword(s):  
Coarse Grained ◽  
The West ◽  
North West ◽  
The Road ◽  
Fine Grained ◽  
Original Order ◽  
The North ◽  
The Hill ◽  
New Evidence ◽  
The Village

During the war a large new quarry was opened in the Longmyndian rocks of Haughmond Hill, Shropshire. It is near the south-east edge of the hill, to the west of the road running north from Upton Magna and one mile from the village. On the sketch-map in the Shrewsbury Memoir (p. 58) two arrows are shown, at about this locality, recording dips of 50° in a south-easterly direction. I was told that there was a very small quarry here before the large quarry was excavated. The present quarry is even larger than that near Haughmond Abbey (Shrewsbury Memoir, p. 48), on the north-west side of the Pre-Cambrian outcrop, and the two quarries offer extensive and splendidly displayed exposures of Longmyndian rocks, one in the coarse-grained Western Longmyndian and the other in the fine-grained Eastern Longmyndian.

Distribution, abundance, population structure and meat yield of the ocean quahog, Arctica islandica, in icelandic waters

1996 ◽  
Vol 76 (4) ◽  
pp. 1107-1114 ◽  
Author(s):  
Gudrún G. Thórarinsdóttir ◽  
Sólmundur T. Einarsson
Keyword(s):  
Population Structure ◽  
Shell Length ◽  
Live Weight ◽  
High Density ◽  
Arctica Islandica ◽  
Meat Yield ◽  
North West ◽  
The North ◽  
Poor Recruitment ◽  
The Mean

A hydraulic dredge survey was conducted during January – June 1994 in north-west, north and east Iceland, to provide a first assessment of ocean quahog, Arctica islandica (Mollusca: Pelecypoda) resources in these areas. Ocean quahog was found in significant concentrations and high density. The combined high-density areas were 91.7 km2 with a minimum biomass (live weight) of 304.80 tonnes. Information on population structure and meat yield were also provided. The population in the areas was characterized by unimodal size distributions comprised of mostly larger-sized individuals. Most quahogs were between 70 and 90 mm with no individuals <17 mm which might be due to the selectivity of the dredge or because of poor recruitment in the population. Little difference was observed when comparing the mean shell length for the quahogs from the three areas. The mean shell length in the north-west area was 75.4 mm and 74.8 mm in the north and east areas. The shell length frequency distribution for the north-west area was different in shape from the two others which were not significantly different from each other. Mean quahog meat yields in the areas were from 30.1 to 33%. The meat yield was highest in the 50.55 mm size class in all areas.

Metasomatism of cherts on the north-west margin of Dartmoor, Devonshire

1967 ◽  
Vol 36 (278) ◽  
pp. 260-273
Author(s):  
M. A. El Sharkawi ◽  
W. R. Dearman
Keyword(s):  
Ferric Iron ◽  
Contact Metamorphism ◽  
Coarse Grained ◽  
Lower Carboniferous ◽  
North West ◽  
Black And White ◽  
The North ◽  
Chemical Transfer ◽  
Reaction Zones ◽  
External Sources

SummaryContact metamorphic and metasomatic effects are described in the black radiolarian cherts of Lower Carboniferous age occurring at varying distances from the margin of the Dartmoor granite in the neighbourhood of Meldon, near Okehampton, Devon.Development of biotite by contact metamorphism is over-printed by metasomatic conversion of chert to coarse-grained calc-silicate hornfels. Changes are localized and controlled by structural planes including faults and joints. Earliest effects are scapolitization giving black-and-white calc-flinta by local addition of calcium and subtraction of silicon. The same trend in transfer of elements is maintained in later phases: wollastonite-diopside reaction zones may enclose cores of black-and-white cale-flinta and are in turn replaced by wollastonite-grossular and grossular reaction zones marking the sites of main channels for migration of mineralizing fluids. Finally, veins with datolite-diopside, datolite-grossular-idocrase, and datolite-grossular-zeolite assemblages were formed in the altered cherts. Tin was available with aluminium and ferric iron during metasomatic changes in which garnet developed.Some chemical transfer may be reciprocal changes with interbedded limestones, but appeal is made to external sources for the later metasomatizing agents.

SEISMIC STRATIGRAPHIC EVALUATION OF A NEOCOMIAN SUBMARINE FAN SYSTEM, BROWSE BASIN, NORTH WEST SHELF

1992 ◽  
Vol 32 (1) ◽  
pp. 171
Author(s):  
L.R. Miller ◽  
W.J. Stuart
Keyword(s):  
High Frequency ◽  
Seismic Reflection ◽  
Low Frequency ◽  
High Amplitude ◽  
Seismic Facies ◽  
Submarine Fan ◽  
North West ◽  
The North ◽  
Braided Channel ◽  
Low Amplitude

A possible submarine fan system of Valanginian age occurs in the south of the western half of Permit WA-212-P in the Browse Basin. Seismic mapping and interpretation have allowed the recognition of five seismic facies which are considered representative of this fan system.The five seismic facies are the upper-middle fan braided channel facies, the upper-middle fan braided interchannel facies, the lower fan channel facies, the lower fan sheet facies, and the lower fan lobe fringe facies. The reflections of the upper-middle braided channel fan facies are discontinuous, disrupted, convex up, low amplitude and high frequency. The interchannel facies has reflections that are concave up, continuous, low frequency and moderate to high amplitude. The lower fan channel facies are recognised by convex up, discontinuous, high frequency and low amplitude reflections. The lower fan sheet facies is noted by mounded configurations with continuous, moderate to high amplitude, moderate frequency reflections. The lower fan lobe fringe facies reflections are flat, often shingled reflections with moderate discontinuity, moderate to high amplitude and low to moderate frequency.Since no wells penetrate the submarine fan, the interpretation is based on seismic reflection configurations which are considered typical of submarine fan segments. The interpreted ancient submarine fan occurs on the basin floor adjacent to a probable ramp type margin, and manifests shape and setting consistent with known submarine fans, such as the Eocene Frigg Fan of the North Sea, and the Lower Cretaceous Barrow Group turbidites in the Carnarvon Basin.Seismic facies mapping, in conjunction with sequence stratigraphy concepts, is particularly useful in areas such as the Browse Basin where considerable marine shale sections exist with little structure, and sequences with reservoir potential continue to be a problem to locate. For instance, in Caswell-1, a well drilled in 1977 immediately north of the permit area, 200 barrels of oil flowed from thin sands within a shale sequence of Albian age. Results of this study indicate that local seismic reflection signatures may be indicative of potential sandstone reservoirs in the vicinity of the study area.

scholarly journals Bed type and flow mechanism of deep water sub-lacustrine fan fringe facies: an example from the Middle Permian Lucaogou Formation in Southern Junggar Basin of NW China

2020 ◽  
Author(s):  
Xin Shan ◽  
Xing-He Yu ◽  
Lina Jin ◽  
Ya-Long Li ◽  
Cheng-Peng Tan ◽  
...  
Keyword(s):  
Deep Water ◽  
Junggar Basin ◽  
High Density ◽  
Middle Permian ◽  
Coarse Grained ◽  
Turbidity Currents ◽  
Depositional System ◽  
Lucaogou Formation ◽  
Flow Mechanisms ◽  
Hybrid Event

AbstractSubmarine or sub-lacustrine lobe deposits are important reservoirs, but the fan fringe deposits form heterogeneities within deep water fan deposits. Fan fringe facies records the complex sediment gravity flow types. By understanding of the bed types and flow mechanisms, we can identify the fan fringe deposit, which aids in the reconstruction of deep water fan and reservoir evaluations. The Jiucaiyuanzi and Dalongkou sections in the West Bogda Mountains preserve well-exposed 536-m and 171-m thick successions, respectively, of a deep water lacustrine depositional system from the Middle Permian Lucaogou Formation. Bed types of the Lucaogou Formation include high-density turbidite, low-density turbidite, incomplete Bouma-type turbidite, hybrid event beds, and slump deposits. The Lucaogou Formation is interpreted here as a fan fringe facies due to the thin bed thickness that characterize turbidites and hybrid event beds, as well as the predominance of the isolated sheet architecture. Previous studies suggest that these deposits were considered as deposited in a deep water setting due to the absence of wave-related structures. The presence of abundant mud clasts in massive medium-coarse grained sandstone beds reflects the significant erosional capability and interactions between high-density turbidity currents and lake floor. The fan fringe facies here contains amalgamated and thick-bedded homolithic facies (~ 30%) and thin-bedded heterolithic facies (~ 70%). The examination of the bed type is of wider significance for facies prediction and reservoir heterogeneity in the sub-lacustrine fan fringe facies.

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