Geology of northeast British Columbia and northwest Alberta: diamonds, shallow gas, gravel, and glaciersThis article introduces a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 509-512 ◽  
Author(s):  
Vic Levson
Keyword(s):  
British Columbia ◽  
Special Issue ◽  
Shallow Gas ◽  
Large Aggregate ◽  
Boreal Plains ◽  
Quaternary Stratigraphy ◽  
Kimberlite Indicator Minerals ◽  
Resource Exploration ◽  
Mapping Techniques ◽  
Indicator Minerals

This special issue reports on some of the results of a multi-disciplinary research program conducted in the Boreal Plains of northwest Alberta and northeast British Columbia. Several innovative approaches to conducting geoscientific research in this remote drift-covered region are presented, including geochemical analysis of bentonites for evaluating kimberlite potential, the use of electromagnetic surveys for mapping buried aggregate deposits, and paleo-topographic mapping techniques to define buried channels. Results of the program include the discovery of several large aggregate deposits, the first kimberlite indicator minerals in northeast British Columbia, a significant sphalerite dispersal train in northwest Alberta, the first documented report of kimberlite-sourced bentonites, and numerous previously unknown interglacial sites. Together these papers provide a greatly enhanced understanding of the glacial history, Quaternary stratigraphy, and kimberlite geology of northwest Alberta and northeast British Columbia and provide an improved framework for resource exploration in the region.

AMS-dated late Pleistocene taiga vole (Rodentia: Microtus xanthognathus) from northeast British Columbia, Canada: a cautionary lesson in chronologyThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 611-618 ◽  
Author(s):  
Richard J. Hebda ◽  
James A. Burns ◽  
Marten Geertsema ◽  
A. J. Timothy Jull
Keyword(s):  
British Columbia ◽  
Late Pleistocene ◽  
Bone Collagen ◽  
Laurentide Ice Sheet ◽  
Special Issue ◽  
Cautionary Note ◽  
Shallow Gas ◽  
Peace River ◽  
Elusive Species ◽  
Selection Of

Dissected colluvial sediments on a Peace River terrace at Bear Flat, northeast British Columbia enclosed a late Pleistocene micromammalian faunule. The fossil remains, including a few loosely articulated skulls and mandibles, were dominated by taiga voles ( Microtus xanthognathus ). The Bear Flat site constitutes the second fossil occurrence in the region of this elusive species, which is unknown in British Columbia in historic times. The late Pleistocene age, determined by accelerator mass spectrometry directly on taiga vole bone collagen, is consistent with the ages of widespread taiga vole records peripheral to the Laurentide ice sheet in western, mid-western, and eastern North America. The presence of allo-chronous remains within a comprehensively dated sedimentary sequence provides a cautionary note about straightforward acceptance of relative stratigraphic dating.

Quaternary stratigraphy and glacial history of the Peace River valley, northeast British ColumbiaThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 549-564 ◽  
Author(s):  
Gregory M.D. Hartman ◽  
John J. Clague
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Quaternary Sediments ◽  
Shallow Gas ◽  
Peace River ◽  
Last Glaciation ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Late Wisconsinan ◽  
Selection Of

Two Cordilleran and three Laurentide glacial advances are recorded in Quaternary sediments and landforms in the Peace River valley, northeast British Columbia. The advances are inferred from fluvial gravels, glaciolacustrine sediments, and tills within nested paleovalleys excavated during three interglaciations and from the distribution of granitoid clasts derived from the Canadian Shield. Till of the last (Late Wisconsinan) Laurentide glaciation occurs at the surface, except where it is overlain by postglacial sediments. The advance that deposited this till was the most extensive in the study area, and the only advance definitively recognized in western Alberta south of the study area. Late Wisconsinan Cordilleran till has not been found in the study area, but Cordilleran and Laurentide ice may have coalesced briefly during the last glaciation. Support for this supposition is provided by the inferred deflection of Laurentide flutings to the southeast by Cordilleran ice. The earliest Laurentide advance may have been the least extensive of the three Laurentide events recognized in the study area. Erratics attributed to this advance occur only east of the Halfway River – Beatton River drainage divide.

Quaternary stratigraphy of the Prophet River, northeastern British ColumbiaThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 565-575 ◽  
Author(s):  
Michelle Trommelen ◽  
Vic Levson
Keyword(s):  
British Columbia ◽  
Oxbow Lake ◽  
Laurentide Ice Sheet ◽  
Glacial Sediments ◽  
Boreal Plains ◽  
Fluvial Terraces ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Late Wisconsinan ◽  
Floodplain Sediments

Exposures in the Prophet River valley in northeast British Columbia provide a unique glimpse into the Quaternary history of the northwest Canadian Boreal Plains. The region shows evidence of Late Wisconsinan Laurentide glaciation in the form of widespread till, containing abundant erratic clasts derived from the Canadian Shield. Vertical sections along the Prophet River expose non-glacial and advance glacial sediments below this till. Pre-Late Wisconsinan non-glacial or interglacial floodplain sediments are interbedded with fluvial gravels at many sites. Macrofossils within horizontally laminated organic-rich black clay and silt indicate deposition on the floodplain of the paleo-Prophet River within an oxbow lake. The climate during deposition is interpreted to be similar to present, supporting a dominantly spruce forest. Wood obtained from eight sites provided non-finite radiocarbon ages, and one sample provided an age of 49 300 ± 2000 BP, which is also considered non-finite. Glaciolacustrine clays and silts, deposited during impoundment of eastward-flowing drainage by the advance of the Laurentide Ice Sheet (LIS) in the Late Wisconsinan, overlie the non-glacial sediments throughout the valley. A blanket of clast-poor, clay-rich till up to 20 m thick, and deposited by the LIS, drapes the glaciolacustrine sediments. Since deglaciation, the Prophet River has incised the valley and formed fluvial terraces at different levels above the modern river.

Mapping Quaternary paleovalleys and drift thickness using petrophysical logs, northeast British Columbia, Fontas map sheet, NTS 94IThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 577-591 ◽  
Author(s):  
Adrian S. Hickin ◽  
Ben Kerr ◽  
Derek G. Turner ◽  
Tom E. Barchyn
Keyword(s):  
British Columbia ◽  
Oil And Gas ◽  
Special Issue ◽  
Quaternary Sediments ◽  
Shallow Gas ◽  
Gas Well ◽  
Well Drilling ◽  
Bedrock Topography ◽  
Petrophysical Logs ◽  
Selection Of

The relatively subdued topography of British Columbia’s northern interior plains does not reflect the irregular, buried bedrock surface. Many areas have been deeply incised by preglacial rivers that have subsequently filled with a succession of Quaternary sediments. In this study, oil and gas petrophysical logs, drill chip samples, water well logs, and surficial and bedrock outcrop maps were used to model the bedrock topography of the Fontas map sheet (NTS 94I). The modelled data produced several depressions that are interpreted to be paleovalleys incised into the soft Cretaceous shale of the Fort St. John Group. Understanding the geometry, thickness, and stratigraphy of the drift has considerable safety and resource management implications as artesian aquifers and natural gas were encountered in the drift during oil and gas well drilling. Four major paleovalleys are suggested. The most dominant paleovalley (Kotcho–Hoffard Paleovalley) is located south of the Etsho Plateau and trends west-southwest across the map area. A second depression occurs within the loop of the Hay River and may be a tributary of the Kotcho–Hoffard Paleovalley that links with the Rainbow Paleovalley in Alberta. A third paleovalley is mapped south of the Sahtaneh River (Kyklo Creek Paleovalley) and is either a tributary to, or crosscuts the Kotcho–Hoffard Paleovalley. The Niteal Creek Paleovalley is located between the Fontas and Sikanni Chief rivers. Its geometry is speculative as there are sparse data, but it may be a tributary of the Kotcho–Hoffard Paleovalley.

scholarly journals What If the ‘Anthropocene’ Is Not Formalized as a New Geological Series/Epoch?

Quaternary ◽  
2018 ◽  
Vol 1 (3) ◽  
pp. 24 ◽  
Author(s):  
Valentí Rull
Keyword(s):  
Present State ◽  
Executive Committee ◽  
Working Group ◽  
Recent Literature ◽  
Special Issue ◽  
Environmental Sciences ◽  
International Union ◽  
Quaternary Stratigraphy ◽  
Wide Range ◽  
Geological Sciences

In the coming years, the Anthropocene Working Group (AWG) will submit its proposal on the ‘Anthropocene’ to the Subcommission of Quaternary Stratigraphy (SQS) and the International Commission on Stratigraphy (ICS) for approval. If approved, the proposal will be sent to the Executive Committee of the International Union of Geological Sciences (IUGS) for ratification. If the proposal is approved and ratified, then the ‘Anthropocene’ will be formalized. Currently, the ‘Anthropocene’ is a broadly used term and concept in a wide range of scientific and non-scientific situations, and, for many, the official acceptance of this term is only a matter of time. However, the AWG proposal, in its present state, seems to not fully meet the requirements for a new chronostratigraphic unit. This essay asks what could happen if the current ‘Anthropocene’ proposal is not formalized by the ICS/IUGS. The possible stratigraphic alternatives are evaluated on the basis of the more recent literature and the personal opinions of distinguished AWG, SQS, and ICS members. The eventual impact on environmental sciences and on non-scientific sectors, where the ‘Anthropocene’ seems already firmly rooted and de facto accepted as a new geological epoch, are also discussed. This essay is intended as the editorial introduction to a Quaternary special issue on the topic.

Ultrabasic eruptives with alnöitic-kimberlitic affinities from Malaita, Solomon Islands

1965 ◽  
Vol 34 (268) ◽  
pp. 16-34 ◽  
Author(s):  
J. B. Allen ◽  
T. Deans
Keyword(s):  
Solomon Islands ◽  
Chemical Analyses ◽  
Alkaline Rocks ◽  
Kimberlite Indicator Minerals ◽  
Host Rocks ◽  
Indicator Minerals

SummaryA detrital assemblage of magnesian ilmenite, pyrope, chrome-diopside, rutile, and zircon has been traced to outcropping ultrabasic alkaline rocks, hitherto unknown in the Melanesian region. Analyses and descriptions of these ‘kimberlite indicator minerals’ are given. The host rocks comprise alnöite, an alnöite breccia with calcite matrix, and a magnesian ankaratrite, which are described, with chemical analyses. Emphasis is laid on the abundance of ultrabasic inclusions and xenocrysts and the replacements and transformations they have undergone. Malaita Island promises to contribute significantly to the understanding of the relations between alnöite, melilite basalts, and kimberlites.

scholarly journals The Tikiusaaq carbonatite: a new Mesozoic intrusive complex in southern West Greenland

2006 ◽  
Vol 10 ◽  
pp. 41-44 ◽  
Author(s):  
Agnete Steenfelt ◽  
Julie A. Hollis ◽  
Karsten Secher
Keyword(s):  
Lithospheric Mantle ◽  
Chemical Elements ◽  
Country Rock ◽  
Alkaline Rock ◽  
Geological Mapping ◽  
Carbonatite Complex ◽  
West Greenland ◽  
Alkaline Rocks ◽  
Kimberlite Indicator Minerals ◽  
Indicator Minerals

Ultrabasic alkaline magmatic rocks are products of melts generated deep within or at the base of the lithospheric mantle. The magmas may reach the surface to form lavas and pyroclastic deposits; alternatively they crystallise at depth to form dykes or central complexes. The rocks are chemically distinct and may contain high concentrations of economically interesting minerals and chemical elements, such as diamonds, niobium, tantalum, rare earth elements, phosphorus, iron, uranium, thorium, and zirconium. Ultrabasic alkaline rocks are known from several provinces in Greenland, but extrusive facies have only been preserved at a few places; e.g. at Qassiarsuk in South Greenland where pyroclastic rocks occur, and in the Maniitsoq region, where a small volcanic breccia (‘Fossilik’) contains fragments of Palaeozoic limestone. Ultramafic lamprophyre and kimberlite are mainly emplaced as dykes, whereas carbonatite forms large intrusive bodies as well as dykes. The ultrabasic alkaline magmas that have been emplaced at certain times during the geological evolution of Greenland can be related to major episodes of continental break-up (Larsen & Rex 1992). The oldest are Archaean and the youngest dated so far are Palaeogene. Figure 1 shows the distribution of known ultrabasic alkaline rocks in West Greenland. The large and well-exposed bodies of alkaline rocks and carbonatites in the Gardar Province were discovered already in the early 1800s (Ussing 1912), while less conspicuous bodies were discovered much later during geological mapping and mineral exploration. Many alkaline rock bodies, particularly dykes, are difficult to identify in the field because they weather more extensively than the country rock gneisses and form vegetated depressions in the landscape. However, their distinct chemistry and mineralogy render alkaline rocks identifiable in geochemical and geophysical survey data. Thus, the Sarfartôq carbonatite complex was discovered during regional airborne gamma-spectrometric surveying owing to its elevated uranium and thorium contents (Secher 1986). The use of kimberlite indicator minerals has led to the discovery of alkaline rocks such as kimberlites and ultramafic lamprophyres that carry fragments of deep lithospheric mantle. Such rocks may also contain diamonds. Kimberlite indicator minerals are high-pressure varieties of minerals, such as garnet, clinopyroxene, chromite and ilmenite that were formed in the lithospheric mantle. Exploration companies have processed thousands of till samples from southern West Greenland for kimberlite indicator minerals and found many new dykes.

About kimberlite indicator minerals in the Triassic tuffs of the Tunguska sineclise

2010 ◽  
Vol 435 (2) ◽  
pp. 1555-1559
Author(s):  
V. P. Afanasiev ◽  
N. S. Tychkov ◽  
N. P. Pokhilenko ◽  
Yu. I. Ovchinnikov
Keyword(s):  
Kimberlite Indicator Minerals ◽  
Indicator Minerals

scholarly journals Introduction

2018 ◽  
Vol 28 (3) ◽  
pp. 407-408
Author(s):  
SARAH ANSARI
Keyword(s):  
British Columbia ◽  
South Asian ◽  
Culture Wars ◽  
First Century ◽  
Stanford University ◽  
Special Issue ◽  
Asian Studies ◽  
Vernacular Literature ◽  
South Asian Studies ◽  
University Of British Columbia

This special issue of the JRAS, guest-edited by Heidi Pauwels University of Washington and Anne Murphy University of British Columbia, brings together an extremely interesting set of articles that collectively explore vernacular perspectives on the emperor Aurangzeb/Alamgir drawn from outside the Persianate heartland of Mughal India. Its beginnings lay in an innovative interdisciplinary panel at the 2014 European Conference on South Asian Studies (ECSAS) held in Zurich in July 2014, which was organised by Heidi and Monika Boehm-Tettelbach (Horstmann). Drawing on vernacular literature, as opposed to more mainstream Persian sources, their authors seek, in various ways, to complicate past and present-day assumptions about the nature of Aurangzeb's rule, how he interacted with his subjects, both Muslim and non-Muslim, and how his subjects in turn viewed him. Aurangzeb (r. 1658–1707 as Alamgir) continues to divide opinion sharply, as reactions to Audrey Truschke's 2017 study Aurangzeb: The Life and Legacy of India's Most Controversial King (Stanford University Press) have recently underlined. Aurangzeb remains a firm fixture in South Asia's twenty-first century ‘culture wars’. By drawing on less-commonly referenced vernacular sources, and hence offering access to less state-centric views of Aurangzeb, this special issue makes a welcome — and very opportune — case for more rounded and nuanced understandings of the emperor and the India in which he lived.

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