Ashton Embry

Ashton Embry
Embry Corp

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Publications (141)
Article
The Sverdrup Basin composite tectono-sedimentary element (SB CTSE) covers 210,000 km2 in the Canadian Arctic Archipelago. The CTSE was initiated in Early Carboniferous by rifting on highly deformed Early Paleozoic strata and contains a maximum of 15 km of Carboniferous to Eocene strata. Eight phases of basin development have been recognized with ea...
Chapter
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We have identifi ed 57 large-magnitude, sequence boundaries in the Phanerozoic succession of the Canadian High Arctic. The characteristics of the boundaries, which include angular unconformities and signifi cant changes in depositional and tectonic regimes across the boundaries, indicate that they were primarily generated by tecton-ics rather than...
Chapter
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The Late Triassic was the time of the Early Cimmerian and Indosinian orogenies that closed the Paleotethys Ocean, which occurred earlier in the Alpine-Carpathian-Mediterranean area, later in the Eastern Europe-Central Asia and latest in the South-East Asia. The Indochina Southeastern Asian and Qiangtang plates were sutured to South China. The new,...
Article
Detrital zircon U-Pb ages are used to provide constraints on the geologic evolution of the sediment source area(s) north of the Sverdrup Basin from the middle Permian to Late Triassic. Previous research on facies relationships and sediment progradation patterns of late Paleozoic and Triassic strata from the northern portion of Sverdrup Basin indica...
Article
Quantitative palynology of the marginal marine and deltaic-fluvial Isachsen Formation of the Sverdrup Basin, Canadian Arctic, provides insight into high latitude climate during much of the Early Cretaceous (Valanginian to early Aptian). Detrended Correspondence Analysis of main pollen and spore taxa is used to derive three ecological groupings infl...
Article
Exceptional exposures of a High Arctic Cretaceous sedimentary record were studied at Glacier Fiord, Axel Heiberg Island. The succession reveals a complex Aptian to Santonian paleoenvironmental history of the Sverdrup Basin that documents several global events. Foraminiferal faunas in combination with rare macrofossil occurrences permit the distinct...
Article
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The Lower Cretaceous Isachsen Formation is a widespread, siliciclastic succession up to 1.4 km thick that records the northwestward progradation of fluvio-deltaic environments into the Sverdrup Basin in the Canadian Arctic. Although the Isachsen Formation is a prominent unit with proven oil and gas reserves, detailed outcrop descriptions of its sed...
Article
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Middle to Upper Devonian strata of the Franklinian Basin in the Canadian Arctic contain a rich record of Phanerozoic tectonic events along the northern margin of Laurentia. We report detrital thermochronometric zircon (U–Th)/He ages (ZHe; number of aliquots, n = 72) and apatite (U–Th)/He ages (AHe; n = 38) from these Paleozoic strata in an effort t...
Article
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Quantitative palynological analyses undertaken on the middle Cretaceous Hassel Formation of the Sverdrup Basin and reputedly equivalent rocks from the Eclipse Trough, about 850 km east, provide convincing evidence that they are coeval and of Late Albian–Cenomanian age. We base this conclusion on statistical definition of two palynomorph populations...
Article
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More than 1800 detrital zircon uraniumlead (U-Pb) ages collected from Franklinian Basin sedimentary strata of the Canadian Arctic Islands provide important insights into the depositional and tectonic evolution of the northern margin of Laurentia from the late Neoproterozoic to the Late Devonian. The Franklinian Basin succession is composed of strat...
Article
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The Early Triassic record, from the Smithian stratotype, shows that the organic carbon isotope record from northwest Pangea closely corresponds to major fluctuations in the inorganic carbon records from the Tethys, indicating truly global perturbations of the carbon cycle occurred during this time. Geochemical proxies for anoxia are strongly correl...
Article
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Nine main petroleum provinces containing recoverable resources totalling 61 Bbbl liquids + 269 Bbbloe of gas are known in the Arctic. The three best known major provinces are: West Siberia-South Kara, Arctic Alaska and Timan-Pechora. They have been sourced principally from, respectively, Upper Jurassic, Triassic and Devonian marine source rocks and...
Data
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The Sverdrup Basin of the Canadian Arctic Archipelago is an established petroliferous, rift/sag basin with 17 discovered oil and gas fields. Almost all the hydrocarbons occur in Triassic-Jurassic shallow marine sandstones and were sourced from Middle to Upper Triassic bituminous shales. The discovered fields occur on the culminations of Palaeogene...
Article
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The 1985 refraction survey based on Ice Island covered a northern transition zone along the Canadian polar margin north of Axel Heiberg Island. The refraction survey included a 60 km line along the inner shelf, a 180 km parallel line along the outer shelf, and a 60 km connecting line. Shotpoints offset from the line ends recorded upper mantle obser...
Article
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Cretaceous volcanic rocks, which consist mainly of basalt flows and pyroclastic rocks, occur on northern Ellesmere Island, Axel Heiberg Island, and northernmost Amund Ringnes Island as part of the Sverdrup Basin succession. Volcanic rocks are associated with each of four regional transgressive–regressive (T–R) cycles that constitute the Cretaceous...
Article
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Transgressive–regressive (T–R) sequence analysis has been applied to the Jurassic succession of the Sverdrup Basin with sequence boundaries drawn at subaerial unconformities or the correlative transgressive surfaces. A hierarchal system of sequence order that reflects the different nature of the boundaries has been formulated on the basis of bounda...
Article
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Detrital zircons from the Lower Cretaceous Isachsen Formation of the Sverdrup Basin, Canadian Arctic Archipelago, have been dated by the U-Pb method and analyzed for Hf isotopes by laser ablation microprobe - inductively coupled plasma - mass spectrometry (LAM-ICP-MS). Five samples from four locations on Ellesmere and Axel Heiberg islands display s...
Article
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Sequence stratigraphy is based, for the most part, on the recognition and correlation of a variety of stratigraphic surfaces that collectively can be characterized as representing changes in depositional trend. Five such surfaces, which are material-based and potentially of regional extent, have been defined and are called a subaerial unconformity,...
Article
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The main source terrains for the Sverdrup Basin of Arctic Canada lay to the south and east and comprised the extensive Canadian and Greenland cratons which were mainly covered by Devonian siliciclastic strata. From Carboniferous to mid-Jurassic, the basin also received sediment from a northern source area, named Crockerland. The Triassic-Jurassic s...
Article
Full-text available
Purpose: Multiple sclerosis (MS), an autoimmune disease of the central nervous system, is often referred to as a multifactorial disease, but there is little consensus as to what factors are involved, besides genetic susceptibility and childhood infectious agents. The purpose of this paper is to identify plausible, environmental factors that contrib...
Article
The Sverdrup Basin is located in the Canadian Arctic Islands. It is 1,000 km by 350 km and is filled with up to 13 km of Carboniferous to Paleogene strata. The basin initially developed in Early Carboniferous as a rift basin upon highly deformed Early Paleozoic strata of the Ellesmerian Orogenic Belt. The development of the basin can be broken into...
Article
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In the Sverdrup Basin (Canadian Arctic), the Lower Triassic Blind Fiord Formation, comprising siltstone and shale, overlies various Middle to Late Permian (post-Wordian) sedimentary units. This formation is subdivided into three members: the Confederation Point, Smith Creek and Svartfjeld members of, respectively, Griesbachian–Dienerian, Smithian–S...
Article
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The establishment of new hygienic conditions plays a role in the appearance of autoimmunity in “westernalised” countries. Consistently, but still unconvincingly, several epidemiological and immunogenetic evidences link the disappearance of malaria with the increase of multiple sclerosis (MS) in Sardinia, insular Italy. To this purpose, we have made...
Data
Based on recent advances in plate tectonics, sedimentology and sequence stratigraphy, I suggest that the Earth is affected by relatively short-lived episodes of increased tectonic activity separated by longer intervals of relative quiescence. If true, this may have important implications for how we interpret the history of the earth and exploit its...
Conference Paper
Full-text available
Detrital zircons from five Paleozoic and Mesozoic sandstones from the Brooks Range and North Slope of Alaska, and two Triassic sandstones from the Sverdrup Basin in northern Canada were dated using SHRIMP and laser ablation ICPMS geochronology. In Alaska, dated samples from allochthonous strata of the Brooks Range include the northern and southern...
Article
Full-text available
Multiple Sclerosis (MS) is an autoimmune disease in which the im- mune-mediated destruction of nerve axons and their protective myelin coating in the central nervous system results in a myriad of serious disabilities. One aspect of MS is the failure of the suppressor side of the immune syst em to cont ain autoimmune reactions. Vitamin D is an estab...
Article
Full-text available
The Sverdrup Basin of the Canadian Arctic Islands contains a sedimentary record, with only short breaks, from Early Carboniferous to Late Cretaceous time and can be used to document the nature of sediments delivered from northern Canada and Greenland. Sm-Nd isotopic analysis of 72 sedimentary rock samples from the Sverdrup Basin, coupled with trace...
Article
Parrish et al. (2001) recently described various facies from the Triassic Shublik Formation of northern Alaska and emphasized the presence of phosphate, glauconite, and a high content of organic carbon in the strata. They interpreted the Shublik Formation as having been deposited under the influence of an upwelling zone on the basis of these distin...
Article
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ABSTRACT The regional thermal history of the north-eastern Sverdrup Basin, Canadian Arctic Archipelago, has been assessed using apatite fission-track thermochronology and vitrinite reflectance data. Fission-track data for 27 samples from six wells through the Mesozoic section on Axel Heiberg and Ellesmere Islands reveal significant Palaeocene cooli...
Article
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A sequence, as originally defined by Sloss and colleagues, was a stratigraphic unit bounded by subaerial unconformities. Such a stratigraphic unit proved to be of limited value because, in most instances, sequences could be recognized only on the margins of a basin where subaerial unconformities were present. Vail and colleagues greatly expanded th...
Article
Article abstract-Objectives: To determine whether there is an excess of respiratory tract infections in the 5-week, 3-month, and 12-month periods before MS symptom onset and if there is an association between MS and a history of infectious mononucleosis (IM). Background: The etiology of MS remains unknown, but infection is frequently suggested as a...
Data
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For the past thirty years the most widely aeeepted model for the opening of Amerasia Basin of the Aretie Oeean has been that the basin openecl by eountereloekwise rotation of northern Alaska and acljaeent Russia (Aretie Alaska plate) away frorn the Canadian Aretie Arehipelago about a pole in the Maekenzie Delta region. Reeently LANE (1997) has eall...
Article
Full-text available
The Franklinian mobile belt of Arctic Canada and Greenland was formed by plate convergence of an unknown landmass with North America during Silurian and Devonian time. Clastic sedimentary units of the thick passive-to convergent-margin sequence seen in the Franklinian mobile belt have been characterized for Nd isotopes and trace element geochemistr...
Article
Calculations of the present geothermal gradient and terrestrial heat flow were made on 156 deep wells of the Canadian Arctic Archipelago. Corrected bottom hole temperature (BHT) data and drill stem test (DST) temperatures were used to determine the thermal gradients for sites for which the quality of data was sufficient. Thermal gradients evaluated...
Article
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A seismic refraction program was carried out on the northeastern polar continental shelf north of Axel Heiberg and Meighen islands. Five distinct velocity units were identified throughout the area. The deepest unit, velocity unit 1, has velocities of 8.2 km/sec and represents the ultramafic, uppermost mantle. The top of this unit is the MOHO and it...
Article
Full-text available
Twelve second-and third-order T-R (transgressive-regressive) sequence boundaries have been delineated in the Triassic succession of the Sverdrup Basin, Arctic Canada. Sequence stratigraphic data from six other localities throughout the world, including Svalbard and Barents Sea, Germany, Italy, eastern Siberia, northern Himalayas and the southwester...
Article
Significant oil and gas accumulations occur in and around Lougheed Island, Arctic Canada, where hydrocarbon prospectivity is controlled by potential source rock distribution and composition. The Middle to Upper Triassic rocks of the Schei Point Group (e.g. Murray Harbour and Hoyle Bay formations) contain a mixture of Types I and II organic matter (...
Article
Full-text available
Significant problems are being encountered by stratigraphers as they attempt to apply Exxonian sequence analysis to the depositional record. The most serious problem is one of consistent and objective boundary recognition. The unconformable portion of the boundary usually can be recognized with reasonable objectivity but a major problem occurs when...
Conference Paper
Full-text available
Conference Paper
Widespread porous and permeable sandstones of the Heiberg Formation/Group (uppermost Triassic-Lower Jurassic) are host to oil and/or gas in sixteen fields in the western Sverdrup Basin of the Canadian Arctic Islands. The sandstones are part of three, third-order, T–R (transgressive–regressive) sequences which are of Rhaetian–Hettangian, Sinemurian...
Conference Paper
Significant thicknesses of organic-rich shales accumulated under predominantly marine depositional conditions in the Arctic region during the Mesozoic era. Deposition of these shales was most prevalent during the Triassic and Late Jurassic, but also extended into the Cretaceous in Arctic North America. Triassic organic-rich shales are represented b...
Conference Paper
The hydrocarbon potential and thermal maturity of rocks from Lougheed Island and its vicinity, central Arctic Archipelago, were evaluated using optical microscopy and Rock-Eval pyrolysis. The Middle to Upper Triassic Schei Point Group contains good to excellent quality oil-prone source intervals (Cape Caledonia Member of the Murray Harbour Formatio...
Article
Full-text available
Recently published Upper Paleozoic and Mesozoic paleogeographic syntheses for Arctic Euramerica (e.g. Ziegler, 1988; Green and Kaplan, 1987) do not include a significant land area to the northwest of the Sverdrup Basin which was the main depocentre in the Canadian Arctic Islands from Carboniferous to Tertiary. However there is substantial geologic...
Article
Organic-rich shales are common in the Ringens Formation/Member, an Oxfordian-Kimmeridgian argillaceous unit which is widespread in the Sverdrup Basin of the Canadian Arctic Archipelago. The shales and siltstones of the Ringnes are laminated to burrowed and are interpreted to have been deposited under sub-oxic conditions in a mid to outer shelf sett...
Conference Paper
Seventeen hydrocarbon fields have been discovered along a fairway which extends from Sabine Peninsula, Melville Island to western Ellef Ringnes Island in the western Sverdrup Basin. The fields are all on structural culminations which have associated faults and fractures. The oil and gas were sourced from Middle and Upper Triassic bituminous shales....