Submarine-fan characteristics and dual sediment provenance, Lower Carboniferous Bragdon Formation, eastern Klamath terrane, California

1989 ◽  
Vol 26 (5) ◽  
pp. 927-940 ◽  
Author(s):  
M. Meghan Miller ◽  
Bingquan Cui
Keyword(s):  
Early Carboniferous ◽  
Sediment Provenance ◽  
Dispersal Pattern ◽  
Submarine Fan ◽  
Lower Carboniferous ◽  
Sediment Dispersal ◽  
Fine Grained ◽  
Rock Fragments ◽  
Western Cordillera ◽  
Volcaniclastic Rocks

The Carboniferous Bragdon Formation comprises sandstone, argillite, and conglomerate, which were deposited in a hybrid submarine-fan setting. The Bragdon Formation contains a crudely progradational succession of sand-rich turbidites and intercalated channel fill and debris flows. Apparent paucity of fine-grained rocks and relatively high sedimentation rates may suggest deposition within a small, rapidly subsiding, ponded basin. Three end-member petrologic sandstone types include (i) quartz-rich, chert-rich, and sedimentary-lithic-rich sandstone, (ii) volcanic-lithic- and feldspar-rich sandstone, and (iii) crystal-rich sandstone and tuffaceous argillite. The compositions reflect basement uplift, arc dissection, and the persistence of volcanism, respectively. Interbedded strata of differing provenance, together with little or no provenance mixing within beds, indicate multicomponent source terranes, line-source sediment dispersal pattern, and limited transport distances.Facies associations and provenance together suggest extension or transtension within an arc-related basinal setting during the Late Devonian and Early Carboniferous, resulting in deposition of epiclastic sediments that were rich in sedimentary rock fragments in a Paleozoic succession otherwise dominated by volcaniclastic rocks or fringing carbonates. Mid-Paleozoic chert-rich epiclastic strata are widespread within the western Cordillera in a variety of tectonic regimes that may be broadly related to the same oblique plate margin.

Palaeomagnetism of the Lower Carboniferous Billefjorden Group, Spitsbergen

1985 ◽  
Vol 122 (4) ◽  
pp. 383-388 ◽  
Author(s):  
D. R. Watts
Keyword(s):  
North America ◽  
Relative Motion ◽  
Early Carboniferous ◽  
Pole Position ◽  
Russian Platform ◽  
Lower Carboniferous ◽  
Fine Grained ◽  
Palaeomagnetic Data ◽  
The Baltic

AbstractPalaeomagnetic data from mid to late Palaeozoic rocks are potentially valuable for testing models of the assembly of Spitsbergen and for determining the palaeo-position of parts of Spitsbergen relative to the major tectonic elements that comprised the Old Red Continent. Fine-grained red sandstones from the Tournaisian to Namurian Billefjorden Group, collected by members of Cambridge Spitsbergen expeditions, were subjected to stepwise chemical and thermal demagnetization. The characteristic magnetization is found in normal and reverse polarities and corresponds to a pole position at 23° S, 332 °E, dp = 5.7°, dm = 10.5°, which is near an early Carboniferous pole computed for the Baltic Shield-Russian Platform (Baltica). When compared to Laurentia (North America) in the context of the revised Mauch Chunk palaeomagnetic study, Spitsbergen falls a few degrees south of the Bullard reconstruction but the error of the determination of the palaeolatitude overlaps with this position. Therefore relative motion between any part of Spitsbergen and Laurentia and Baltica during the Carboniferous is not resolved.

Evidence for pyroclastic emplacement of the Crowsnest Formation, Alberta

1996 ◽  
Vol 33 (5) ◽  
pp. 715-728 ◽  
Author(s):  
R.N. Adair ◽  
R.A. Burwash
Keyword(s):  
Elevated Temperatures ◽  
Pyroclastic Flows ◽  
Coarse Grained ◽  
Rock Fragment ◽  
Fine Grained ◽  
Rock Fragments ◽  
Explosive Phase ◽  
Graded Structures ◽  
Textural Evidence ◽  
Charred Wood

The middle Cretaceous Crowsnest Formation west of Coleman, Alberta, is composed of bedded alkaline volcanic deposits containing heterolithic volcanic rock fragments and crystal clasts. Comparison with modern examples of subaerial pyroclastic rocks suggests that pyroclastic flows, surges, fallout of material from vertical eruption columns, and minor mud flows emplaced the deposits. Textural evidence in the form of plastically deformed volcanic fragments, chilled deposit margins, baked rock fragment margins, recrystallization, and the presence of charred wood and charred wood molds indicate emplacement at elevated temperature. Massive deposits containing a fine-grained basal zone are interpreted as the product of pyroclastic flows, whereas deposits characterized by a block-rich base overlain by a thin layer of block-depleted stratified material are interpreted as the product of density-stratified surges. Deposits exhibiting pronounced stratification were emplaced by ash-cloud surges. Thickly bedded breccias exhibiting rheomorphic textures were emplaced as vent-proximal pyroclastic flows. Deposits characterized by parallel beds and graded structures are interpreted as fallout tephra deposits, and deposition by lahars is indicated by coarse-grained beds that lack evidence for emplacement at elevated temperatures. The eruptions of the Crowsnest Formation were cyclical. An initial explosive phase generated deposits by pyroclastic flows, surges, fallout, and lahars. As an eruption progressed, it evolved into a poorly gas-charged effusive stage that emplaced coarsely porphyritic domes, plugs, spines, and vent-proximal lava flows. Subsequent eruptions destroyed the effusive vent facies deposits and produced abundant heterolithic clasts typical of the formation.

scholarly journals The origin and early radiation of terrestrial vertebrates

2001 ◽  
Vol 75 (6) ◽  
pp. 1202-1213 ◽  
Author(s):  
Robert L. Carroll
Keyword(s):  
Fossil Record ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Lower Carboniferous ◽  
Major Transitions ◽  
Terrestrial Vertebrates ◽  
History Of ◽  
Paleozoic Tetrapods ◽  
Early Radiation ◽  
Ways Of Life

The origin of tetrapods from sarcopterygian fish in the Late Devonian is one of the best known major transitions in the history of vertebrates. Unfortunately, extensive gaps in the fossil record of the Lower Carboniferous and Triassic make it very difficult to establish the nature of relationships among Paleozoic tetrapods, or their specific affinities with modern amphibians. The major lineages of Paleozoic labyrinthodonts and lepospondyls are not adequately known until after a 20–30 m.y. gap in the Early Carboniferous fossil record, by which time they were highly divergent in anatomy, ways of life, and patterns of development. An even wider temporal and morphological gap separates modern amphibians from any plausible Permo-Carboniferous ancestors. The oldest known caecilian shows numerous synapomorphies with the lepospondyl microsaur Rhynchonkos. Adult anatomy and patterns of development in frogs and salamanders support their origin from different families of dissorophoid labyrinthodonts. The ancestry of amniotes apparently lies among very early anthracosaurs.

scholarly journals Stratigraphy and depositional history of the Upper Palaeozoic and Triassic sediments in the Wandel Sea Basin, central and eastern North Greenland

1989 ◽  
Vol 143 ◽  
pp. 21-45
Author(s):  
L Stemmerik ◽  
E Håkansson
Keyword(s):  
Early Carboniferous ◽  
Upper Permian ◽  
Lower Permian ◽  
Late Permian ◽  
The West ◽  
Depositional History ◽  
Lower Carboniferous ◽  
Upper Carboniferous ◽  
Lithostratigraphic Units ◽  
History Of

A lithostratigraphic scheme is erected for the Lower Carboniferous to Triassic sediments of the Wandel Sea Basin, from Lockwood Ø in the west to Holm Land in the east. The scheme is based on the subdivision into the Upper Carboniferous - Lower Permian Mallemuk Mountain Group and the Upper Permian - Triassic Trolle Land Group. In addition the Upper Carboniferous Sortebakker Formation and the Upper Permian Kap Kraka Formation are defined. Three formations and four members are included in the Mallemuk Mountain Group. Lithostratigraphic units include: Kap Jungersen Formation (new) composed of interbedded limestones, sandstones and shales with minor gypsum - early Moscovian; Foldedal Formation composed of interbedded limestones and sandstones -late Moseovian to late Gzhelian; Kim Fjelde Formation composed of well bedded Iimestones - late Gzhelian to Kungurian. The Trolle Land Group includes three formations: Midnatfjeld Formation composed of dark shales, sandstones and limestones - Late Permian; Parish Bjerg Formation composed of a basal conglomeratic sandstone overlain by shales and sandstones - ?Early Triassic (Scythian); Dunken Formation composed of dark shales and sandstones - Triassic (Scythian-Anisian). The Sortebakker Formation (new) is composed of interbedded sandstones, shales and minor coal of floodplain origin. The age is Early Carboniferous. The Kap Kraka Formation (new) includes poorly known hematitic sandstones, conglomerates and shales of Late Permian age.

scholarly journals Stratigraphy and lithogeochemistry of the Goldenville horizon and associated rocks, Baie Verte Peninsula, Newfoundland

2021 ◽  
Author(s):  
C Mueller ◽  
S J Piercey ◽  
M G Babechuk ◽  
D Copeland
Keyword(s):  
Gold Mineralization ◽  
Iron Formation ◽  
Fine Grained ◽  
Hydrothermal Sediment ◽  
Post Archean Australian Shale ◽  
Oxygenated Water ◽  
Volcaniclastic Rocks ◽  
Laurentian Margin ◽  
Mn Oxides ◽  
Hydrothermal Venting

The Goldenville horizon in the Baie Verte Peninsula is an important stratigraphic horizon that hosts primary (Cambrian to Ordovician) exhalative magnetite and pyrite and was a chemical trap for younger (Silurian to Devonian) orogenic gold mineralization. The horizon is overlain by basaltic flows and volcaniclastic rocks, is intercalated with variably coloured argillites and cherts, and underlain by mafic volcaniclastic rocks; the entire stratigraphy is cut by younger fine-grained mafic dykes and coarser gabbro. Lithogeochemical signatures of the Goldenville horizon allow it to be divided into high-Fe iron formation (HIF; >50% Fe2O3), low-Fe iron formation (LIF; 15-50% Fe2O3), and argillite with iron minerals (AIF; <15% Fe2O3). These variably Fe-rich rocks have Fe-Ti-Mn-Al systematics consistent with element derivation from varying mineral contributions from hydrothermal venting and ambient detrital sedimentation. Post-Archean Australian Shale (PAAS)-normalized rare earth element (REE) signatures for the HIF samples have negative Ce anomalies and patterns similar to modern hydrothermal sediment deposited under oxygenated ocean conditions. The PAAS-normalized REE signatures of LIF samples have positive Ce anomalies, similar to hydrothermal sediment deposited under anoxic to sub-oxic conditions. The paradoxical Ce behaviour is potentially explained by the Mn geochemistry of the LIF samples. The LIF have elevated MnO contents (2.0-7.5 weight %), suggesting that Mn from hydrothermal fluids was oxidized in an oxygenated water column during hydrothermal venting, Mn-oxides then scavenged Ce from seawater, and these Mn-oxides were subsequently deposited in the hydrothermal sediment. The Mn-rich LIF samples with positive Ce anomalies are intercalated with HIF with negative Ce anomalies, both regionally and on a metre scale within drill holes. Thus, the LIF positive Ce anomaly signature may record extended and particle-specific scavenging rather than sub-oxic/redox-stratified marine conditions. Collectively, results suggest that the Cambro-Ordovician Taconic seaway along the Laurentian margin may have been completely or near-completely oxygenated at the time of Goldenville horizon deposition.

scholarly journals Lower Permian basaltic agglomerate from the Tsengel River valley, Mongolian Altai

2020 ◽  
Vol 51 ◽  
pp. 1-11
Author(s):  
Kristýna Hrdličková ◽  
Altanbaatar Battushig ◽  
Pavel Hanžl ◽  
Alice Zavřelová ◽  
Jitka Míková
Keyword(s):  
River Valley ◽  
Lower Permian ◽  
Basalt Lava ◽  
Volcanic Arc ◽  
Lower Carboniferous ◽  
Upper Carboniferous ◽  
Mongolian Altai ◽  
Icp Ms ◽  
Volcaniclastic Rocks ◽  
Data Yield

A new occurrence of Permian volcanic and volcaniclastic rocks in the Mongolian Altai south of the Main Mongolian Lineament was described between soums of Tugrug and Tseel in Gobi-Altai aimag. Studied vitrophyric pyroxene basalt lies in a layer of agglomerate and amygdaloidal lavas, which is a part of NE–SW trending subvertical sequence of varicolored siltstones and volcaniclastic rocks in the Tsengel River valley. This high-Mg basalt is enriched in large ion lithophile elements, Pb and Sr and depleted in Nb and Ta. LA-ICP-MS dating on 44 spots reveals several concordia clusters. The whole rock geochemistry of sample fits volcanic arc characteristic in the geotectonic discrimination diagrams. Dominant zircon data yield Upper Carboniferous and Permian magmatic ages 304.4 ± 2.3 and 288.6 ± 1.9 Ma. Two smaller clusters of Upper Devonian (376 ± 4.7 Ma) to Lower Carboniferous ages (351.9 ± 3.5 Ma) indicate probably contamination of ascending magmatic material. Youngest Triassic age found in three morphologically differing grains reflects probably lead loss. Described high-Mg basalt lava represents sub-aerial volcanism in volcanic arc environment developed over the N dipping subduction zone in the southwestern Mongolia in the time span from Uppermost Carboniferous to Permian during terminal stage of its activity.

scholarly journals Characterization of glacial silt and clay using automated mineralogy

2019 ◽  
Vol 60 (80) ◽  
pp. 49-65
Author(s):  
Jeff W. Crompton ◽  
Gwenn E. Flowers ◽  
Brendan Dyck
Keyword(s):  
Grain Size ◽  
Size Composition ◽  
Rock Properties ◽  
Fine Grained ◽  
Rock Fragments ◽  
Grain Sizes ◽  
Automated Mineralogy ◽  
Log Normal ◽  
Discrete Populations

AbstractGlacial erosion produces vast quantities of fine-grained sediment that has a far-reaching impact on Earth surface processes. To gain a better understanding of the production of glacial silt and clay, we use automated mineralogy to quantify the microstructure and mineralogy of rock and sediment samples from 20 basins in the St. Elias Mountains, Yukon, Canada. Sediments were collected from proglacial streams, while rock samples were collected from ice marginal outcrops and fragmented using electrical pulse disaggregation. For both rock fragments and sediments, we observe a log-normal distribution of grain sizes and a sub-micrometer terminal grain size. We find that the abrasion of silt and clay results in both rounding and the exploitation of through-going fractures. The abundance of inter- versus intragranular fractures depends on mineralogy and size. Unlike the relatively larger grains, where crushing and abrasion are thought to exploit and produce discrete populations of grain sizes, the comminution of fines leads to a grain size, composition and rounding that is continuously distributed across size, and highly dependent on source-rock properties.

Clay mineralogy, fine-grained sediment dispersal, and inferred current patterns, lower Cook Inlet and Kodiak shelf, Alaska

1979 ◽  
Vol 24 (3-4) ◽  
pp. 291-306 ◽  
Author(s):  
James R. Hein ◽  
Arnold H. Bouma ◽  
Monty A. Hampton ◽  
C. Robin Ross
Keyword(s):  
Clay Mineralogy ◽  
Cook Inlet ◽  
Sediment Dispersal ◽  
Fine Grained

New play type, southern Bonaparte Basin-Petrel Sub-basin—WA-442-P and NT/P81 exploration permits

2012 ◽  
Vol 52 (1) ◽  
pp. 525
Author(s):  
Margaret Hildick-Pytte
Keyword(s):  
Seismic Data ◽  
Early Carboniferous ◽  
Oil Fields ◽  
Source Rocks ◽  
Lower Carboniferous ◽  
Petroleum Systems ◽  
Seismic Data Acquisition ◽  
Early Palaeozoic ◽  
Hydrocarbon Charge ◽  
3D Seismic Data

Recent investigation, including mapping re-processed seismic data, suggests there is deeper hydrocarbon potential in the WA-442-P and NT/P81 exploration permits beneath the Early Carboniferous Tanmurra Formation horizon. Earlier interpretation of the area showed tilted fault blocks commonly thought of as economic basement in the vicinity of the Turtle and Barnett oil fields and extending to the northwest to connect with the Berkley Platform. The deep-gas play type is structural and is believed to be two nested three-way dip anticlines developed against a large bounding fault to the northeast, with axial trends northwest to southeast, and axial plane curving towards the northeast for the deeper structure. This play type is believed to be associated with structural compression and movement along the master fault with incremental re-activation most recently during the Cainozoic as recorded in overlying sediments. The Nova Structure and the deeper Super Nova structure have closures of about 450 and 550 km2, respectively. The sediments beneath the Nova horizon are believed to be of Devonian Frasnian-Famennian age but have not been drilled offshore in the Southern Bonaparte Basin (Petrel Sub-basin). Earlier work suggests that there are two petroleum systems present in the southern Bonaparte Basin, a Larapintine source from Early Palaeozoic Devonian to Lower Carboniferous source rocks, and a transitional Larapintine/Gondwana system sourced from Lower Carboniferous to Permian source rocks. Hydrocarbon charge for the structures is most likely from the Larapintine source rock intervals or yet to be identified older intervals associated with the salt deposition during the Ordovician and Silurian. Independent estimates place close to 7 TCF (trillion cubic feet) of gas in the Nova Structure. New 3D seismic data acquisition is planned over the structures to better define the geology and ultimately delineate well locations.

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