Postglacial evolution of a Pacific coastal fjord in British Columbia, Canada: interactions of sea-level change, crustal response, and environmental fluctuations — results from MONA core MD02-2494This article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.

2008 ◽  
Vol 45 (11) ◽  
pp. 1345-1362 ◽  
Author(s):  
Audrey Dallimore ◽  
Randolph J. Enkin ◽  
Reinhard Pienitz ◽  
John R. Southon ◽  
Judith Baker ◽  
...  
Keyword(s):  
British Columbia ◽  
Sea Level ◽  
Radiocarbon Dates ◽  
Polar Climate ◽  
The Core ◽  
Mantle Viscosity ◽  
Climate Stability ◽  
Viscosity Models ◽  
New Information ◽  
Effingham Inlet

The sedimentary record in a 40.9 m giant (Calypso) piston core (MD02-2494) raised from the inner basin within Effingham Inlet, British Columbia, Canada, during the 2002 Marges Ouest Nord Américaines (MONA) campaign, spans from 14 360 14C years BP (17 300 calibrated calendar (cal.) years BP) to about nine centuries before present. The core archives changes in sedimentation and sea level immediately following deglaciation of the Late Wisconsin Fraser Glaciation, which peaked about 15 000 14C years BP. The presence of the Mazama Ash in the core anchors a detailed chronology based on 49 radiocarbon dates and seven Pleistocene paleomagnetic secular variation correlations. Diatom assemblages identify a marine–freshwater–marine transition in the basin, which occurred 11 630 14C years BP (13 500 cal. years BP). At this time, a bedrock sill, presently at 46 m depth, was briefly exposed as sea level fell and then rose again during isostatic crustal adjustments. These data constrain a new sea-level curve for the outer coast of Vancouver Island covering the past 12 000 14C years BP (14 000 cal. years BP), providing new information on the nature of deglaciation along the west coast of Canada and informing interpretations of regional paleoceanographic records and mantle viscosity models.

A new high-resolution radiocarbon Bayesian age model of the Holocene and Late Pleistocene from core MD02-2494 and others, Effingham Inlet, British Columbia, Canada; with an application to the paleoseismic event chronology of the Cascadia Subduction Zone

2013 ◽  
Vol 50 (7) ◽  
pp. 746-760 ◽  
Author(s):  
Randolph J. Enkin ◽  
Audrey Dallimore ◽  
Judith Baker ◽  
John R. Southon ◽  
Tara Ivanochko
Keyword(s):  
British Columbia ◽  
High Resolution ◽  
Subduction Zone ◽  
Laminated Sediments ◽  
Cascadia Subduction Zone ◽  
K Value ◽  
Radiocarbon Dates ◽  
Age Model ◽  
Annually Laminated Sediments ◽  
Effingham Inlet

Annually laminated sediments from the anoxic inner basin of Effingham Inlet, Pacific coast of Vancouver Island, British Columbia, Canada, yield a high-resolution 42 m paleoenvironmental record, from the present to about 14 ka 14C BP (17 ka cal BP). A new age model, based on 68 radiocarbon dates from twigs and small plant material, from the 40 m core MD02-2494 and 2 m freeze cores from the surface, is anchored by the Mazama Ash and varve counting. A Poisson-process sedimentation model is used, applying a new method to determine the Poisson k value, giving a realistic age model compatible with the multi-proxy core data. Twenty-one “seismites”, which are lithofacies in the Effingham cores that may be representative of seismically triggered mass-wasting events, are identified and dated precisely, then compared with the chronology of the deep-sea turbidite record farther south in the Cascadia Subduction Zone (CSZ), to determine if regional sediment disturbances can be identified. With 16 proposed correlations, Effingham seismite ages are 169 ± 206 years older than turbidite ages estimated largely by radiocarbon analysis of foraminifera in hemipelagic deposits.

scholarly journals An investigation into the sensitivity of postglacial decay times to uncertainty in the adopted ice history

2019 ◽  
Author(s):  
Joseph Kuchar ◽  
Glenn Milne ◽  
Alexander Hill ◽  
Lev Tarasov ◽  
Maaria Nordman
Keyword(s):  
Sea Level ◽  
Decay Time ◽  
Upper Mantle ◽  
Lower Mantle ◽  
Solution Space ◽  
Hudson Bay ◽  
James Bay ◽  
Mantle Viscosity ◽  
Viscosity Models ◽  
Decay Times

Abstract At the centers of previously glaciated regions such as Hudson Bay in Canada and the Gulf of Bothnia in Fennoscandia, it has been observed that the sea level history follows an exponential form and that the associated decay time is relatively insensitive to uncertainty in the ice loading history. We revisit the issue of decay time sensitivity by computing relative sea level histories for Richmond Gulf and James Bay in Hudson Bay and Ångerman River in Sweden for a suite of reconstructions of the North American and Fennoscandian Ice Sheets and Earth viscosity profiles. We find that while some Earth viscosity models do indeed show insensitivity in computed decay times to the ice history, this is not true in all cases. Moreover, we find that the location of the study site relative to the geometry of the ice sheet is an important factor in determining ice sensitivity, and based on our set of ice sheet reconstructions, conclude that the location of James Bay is not well-suited to a decay time analysis. We describe novel corrections to the RSL data to remove the effects associated with the spatial distribution of sea level indicators as well as for other signals unrelated to regional ice loading (ocean loading, rotation and global mean sea-level changes) and demonstrate that they can significantly affect the inference of viscosity structure. We performed a forward modelling analysis based on a commonly adopted 2-layer, sub-lithosphere viscosity structure to determine how the solution space of viscosity models changes with the input ice history at the three study sites. While the solution spaces depend on ice history, for both Richmond Gulf and Ångerman River there are regions of parameter space where solutions are common across all or most ice histories, indicating low ice load sensitivity for these mantle viscosity parameters. For example, in Richmond Gulf, upper mantle viscosity values of (0.3–0.5)x1021 Pa s and lower mantle viscosity values of (5–50)x1021 Pa s tend to satisfy the data constraint consistently for most ice histories considered in this study. Similarly, the Ångerman River solution spaces contain a solution with an upper mantle viscosity of 0.3 × 1021 Pa s and lower mantle viscosity values of (5–50)x1021 Pa s common to 9 of the 10 ice histories considered there. However, the dependence of the viscosity solution space on ice history suggests that joint estimation of ice and Earth parameters is the optimal approach.

Geochemical reconstruction of Pacific decadal variability from the eastern North Pacific during the HoloceneThis article is one of a series of papers published in this Special Issue on the theme Polar Climate Stability Network.

2008 ◽  
Vol 45 (11) ◽  
pp. 1317-1329 ◽  
Author(s):  
Tara S. Ivanochko ◽  
Stephen E. Calvert ◽  
Richard E. Thomson ◽  
Thomas F. Pedersen
Keyword(s):  
North Pacific ◽  
Decadal Variability ◽  
High Elevation ◽  
Early Holocene ◽  
Aleutian Low ◽  
Polar Climate ◽  
Climate Stability ◽  
The Pacific ◽  
Age Model ◽  
Effingham Inlet

Determining climate variations over the Holocene requires high-resolution records with well-developed age models. A 40 m long marine sediment core raised from Effingham Inlet, an anoxic fjord on the west coast of Vancouver Island, British Columbia, Canada, yields such a record. Forty six 14C accelerator mass spectrometry (AMS) dates determined from terrestrial plant material form the age model. Downcore sampling at both 5 cm (20 year) and 1.5 cm (7 year) resolution indicates that high-frequency oceanographic variability has prevailed at this site over the last 10 000 years. Spectral analysis of wt.% opal, a proxy for diatom productivity in the basin, reveals the bidecadal and pentadecadal periods of the Pacific decadal oscillation (PDO) – North Pacific index (NPI) that are related to changes in the strength of the Aleutian Low. Coherence analysis between the Effingham Inlet data and δ18O records from Jellybean Lake (a high elevation site in southwest Yukon) indicates regional coherence at periods of 45, 70, and 510 years between productivity in Effingham Inlet and changes in the Aleutian Low strength. Over the entire Holocene, the strength of decadal variability has changed. Both 20- and 50-year periods are present to some degree in the early Holocene, and only the 50 year period is evident in the late Holocene. These data imply that regime shifts would have been more frequent in the early Holocene relative to the last several thousand years.

scholarly journals Relative Sea-Level Change in the Northern Strait of Georgia, British Columbia*

2007 ◽  
Vol 59 (2-3) ◽  
pp. 113-127 ◽  
Author(s):  
Thomas S. James ◽  
Ian Hutchinson ◽  
J. Vaughn Barrie ◽  
Kim W. Conway ◽  
Darcy Mathews
Keyword(s):  
British Columbia ◽  
Sea Level ◽  
Sea Level Change ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Strait Of Georgia ◽  
Level Change ◽  
Decay Times ◽  
Crustal Uplift ◽  
Cordilleran Ice Sheet

Abstract Twenty-four new radiocarbon dates from isolation basin cores, excavations and natural exposures, and an archeological site, constrain relative sea-level change since the last glaciation in the northern Strait of Georgia, British Columbia. Relative sea level fell rapidly from about 150 m elevation to 45 m elevation from 11 750 to 11 000 BP (13 750 to 13 000 cal BP), then its rate of fall slowed. The initial rapid emergence began soon after the transition from proximal to distal glaciomarine sedimentation, when the glacial front retreated from the Strait of Georgia and the Earth’s surface was unloaded. A sea-level lowstand a few metres below present-day sea level may have occurred in the early Holocene, but sea level was near its present level by 2000 BP. Sea-level change in the northern Strait of Georgia lagged the mid Strait of Georgia, 80 km to the south, by a few hundred years during initial emergence. The lowstand in the northern strait was later and probably shallower than in the mid strait. Isostatic depression inferred from the sea-level observations can be fit with two decaying exponential terms with characteristic decay times of 500 and 2600 years. The faster decay time corresponds to a shallow mantle viscosity of about 1019 Pa s, consistent with previous glacio-isostatic modelling. The present-day crustal uplift rate from the residual isostatic effects of the Cordilleran Ice Sheet is about 0.25 mm/a. Crustal uplift is not expected to significantly ameliorate projected sea-level rise in the mid and northern Strait of Georgia because present-day vertical crustal movements are inferred to be small.

The importance of stock herding and dairying in the Neolithic Balkans and the subsistence diversity

2020 ◽  
Author(s):  
Darko Stojanovski ◽  
Ivana Živaljević ◽  
Vesna Dimitrijević ◽  
Julie Dunne ◽  
Richard Evershed ◽  
...  
Keyword(s):  
Milk Proteins ◽  
Domestic Animal ◽  
Dental Calculus ◽  
Isotopic Study ◽  
Radiocarbon Dates ◽  
The Balkans ◽  
Animal Remains ◽  
New Information ◽  
Archaeological Materials ◽  
Ceramic Vessels

The application of biomolecular techniques to archaeological materials from the Balkans is providing valuable new information on the prehistory of the region. This is especially relevant for the study of the neolithisation process in SE Europe, which gradually affected the rest of the continent. Here, to answer questions regarding diet and subsistence practices in early farming societies, we combine organic residue analyses of archaeological pottery, taxonomic and isotopic study of domestic animal remains and biomolecular analyses of human dental calculus. The results from the analyses of the lipid residues from pottery suggest that milk was processed in ceramic vessels. Dairy products were shown to be part of the subsistence strategies of the earliest Neolithic communities in the region but were of varying importance in different areas of the Balkan. On the other hand, we did not confidently detect any milk proteins within the dental calculus. The molecular and isotopic identification of meat, dairy, plants and beeswax in the pottery lipids also provided insights into the diversity of diet in these early Neolithic communities. We also present the first compound-specific radiocarbon dates for the region, obtained directly on absorbed organic residues extracted from pottery, identified as dairy lipids.

Ecotypic variation affects the conservation of North American badgers endangered along their northern range extent

2018 ◽  
Author(s):  
Richard D. Weir ◽  
Trevor A. Kinley ◽  
Richard W. Klafki ◽  
Clayton D. Apps
Keyword(s):  
British Columbia ◽  
Cause Of Death ◽  
Conservation Strategies ◽  
High Fecundity ◽  
Ecological Information ◽  
The Core ◽  
Ecotypic Variation ◽  
Sufficient Energy ◽  
Soil Deposits ◽  
Regional Conservation

This chapter is based on ecological information on 82 radio-tagged badgers (39 F, 43 M) among three study populations in British Columbia, Canada between 1996 and 2010, data that were collected to learn more about the ecology of badgers and consider how variation in their ecology might inform regional conservation strategies. The widely spaced, lower density prey and distribution of soil deposits suitable for digging in British Columbia likely required badgers to use substantially larger areas, relative to the core range, in which to acquire sufficient energy to survive and reproduce. Strikes from automobiles were the primary cause of death among all radio-tagged badgers and this source of mortality is pervasive throughout the limited distribution of badgers in British Columbia. Despite their potential for high fecundity, populations of badgers in British Columbia likely remain at considerable risk compared to those in the core of the species’ range.

scholarly journals Presuppositions, implicatures, and contextual equivalence

2021 ◽  
Author(s):  
Paul Marty ◽  
Jacopo Romoli
Keyword(s):  
Linguistic Theory ◽  
Empirical Adequacy ◽  
The Novel ◽  
Systematic Comparison ◽  
The Core ◽  
New Information ◽  
Maximize Presupposition ◽  
Important Challenge ◽  
Contextual Equivalence

AbstractMaximize Presupposition! (MP), as originally proposed in Heim (Semantik: Ein internationales Handbuch der zeitgenössischen Forschung, pp. 487–535, 1991) and developed in subsequent works, offers an account of the otherwise mysterious unassertability of a variety of sentences. At the core of MP is the idea that speakers are urged to use a sentence ψ over a sentence ϕ if ψ contributes the same new information as ϕ, yet carries a stronger presupposition. While MP has been refined in many ways throughout the years, most (if not all) of its formulations have retained this characterisation of the MP-competition. Recently, however, the empirical adequacy of this characterisation has been questioned in light of certain newly discovered cases that are infelicitous, despite meeting MP-competition conditions. This has led some researchers to broaden the scope of MP, extending it to competition between sentences which are not contextually equivalent (Spector and Sudo in Linguistics and Philosophy 40(5):473–517, 2017) and whose presuppositions are not satisfied in the context (Anvari in Proceedings of Semantics and Linguistic Theory 28, pp. 711–726, 2018; Manuscript, IJN-ENS, 2019). In this paper, we present a body of evidence showing that these formulations of MP are sometimes too liberal, sometimes too restrictive: they overgenerate infelicity for a variety of felicitous cases while leaving the infelicity of minimally different cases unaccounted for. We propose an alternative, implicature-based approach stemming from Magri (PhD dissertation, MIT, 2009), Meyer (PhD dissertation, MIT, 2013), and Marty (PhD dissertation, MIT, 2017), which reintroduces contextual equivalence and presupposition satisfaction in some form through the notion of relevance. This approach is shown to account for the classical and most of the novel cases. Yet some of the latter remain problematic for this approach as well. We end the paper with a systematic comparison of the different approaches to MP and MP-like phenomena, covering both the classical and the novel cases. All in all, the issue of how to properly restrict the competition for MP-like phenomena remains an important challenge for all accounts in the literature.

Bridge River tephra: revised distribution and significance for detecting old carbon errors in radiocarbon dates of limnic sediments in southern British Columbia

1980 ◽  
Vol 17 (11) ◽  
pp. 1454-1461 ◽  
Author(s):  
Rolf W. Mathewes ◽  
John A. Westgate
Keyword(s):  
British Columbia ◽  
Sedimentary Rocks ◽  
Lacustrine Sediments ◽  
Igneous Rocks ◽  
The South ◽  
Radiocarbon Dates ◽  
Carbon Contamination ◽  
Horseshoe Lake ◽  
Tephra Beds

Ash-grade Bridge River tephra, identified as such on the basis of shard habit, modal mineralogy, and composition of ilmenite, occurs in sedimentary cores from three lakes located to the south of the previously documented plume and necessitates a significant enlargement of the fallout area of that tephra in southwestern British Columbia.These new, more southerly occurrences are probably equivalent to the ~2350 year old Bridge River tephra, although it can be argued from the evidence at hand that the 14C dates and biotite-rich nature support relationship to a slightly earlier Bridge River event.Large differences exist in the 14C age of sediments immediately adjacent to the Bridge River tephra at these three lake sites; maximum ages of 3950 ± 170 years BP (GX-5549) and 3750 ± 210 years BP (I-10041) were obtained at Phair and Fishblue lakes, respectively, whereas the corresponding age at Horseshoe Lake is only 2685 ± 180 years BP (GX-5757). The two older dates are considered to be significantly affected by old carbon contamination for the bedrock locally consists of calcareous sedimentary rocks and the lacustrine sediments are very calcareous. The 14C date from Horseshoe Lake, which occurs in an area of igneous rocks, appears to be only slightly too old relative to the ~2350 year old Bridge River tephra.Well-dated tephra beds, therefore, can be very useful in assessing the magnitude of old carbon errors associated with radiocarbon dates based on limnic sediments. Calcareous gyttja deposits beneath Bridge River tephra within the study area exhibit old carbon errors of the order of 1350–1550 years.

The Base and Top of the Coral-rock in Barbados

1937 ◽  
Vol 74 (8) ◽  
pp. 337-359 ◽  
Author(s):  
C. T. Trechmann
Keyword(s):  
Sea Level ◽  
The South ◽  
The West ◽  
East Part ◽  
Varying Thickness ◽  
South West ◽  
New Information ◽  
Main Portion ◽  
Coral Rock

1. The coral-rock commences nearly everywhere with a basal bed of varying thickness containing a fauna of pre-Pleistocene aspect among which the genus Haliotis (absent from these coasts at the present day), Pleurotomaria, Meiocardia, etc., are noticeable. This faunule may have lived at a depth of 700–1,000 feet.2. The supposition that the southerly anticlines are a later uplift than the main portion of Barbados is supported by the absence of ravines, and the presence of post-coral-rock beds which occur as coastal veneers at low altitudes, and in greater thickness in the south-east corner near Whitehaven.3. The south-east part of the island from Consett Point to Ragged Point has probably extended further seawards in comparatively recent times ; the series of converging faults and dislocations in the cliff sections suggest that the thrusts from the west or south-west may have been resisted by this part of the island.4. The relative claims of fault-scarping or marine erosion in production of the rising terraces is discussed ; and new information regarding the thickness of the coral-rock at sea-level from a boring is detailed.5. The finding of a faunule with Pliocene or possibly Miocene affinities at the base of the coral-rock puts the Oceanic series further back, into the Miocene.

Lexical Arguments and Information Types in Malay Oral Narratives

2015 ◽  
Vol 7 (1) ◽  
pp. 80-97
Author(s):  
Siaw-Fong Chung
Keyword(s):  
Information Flow ◽  
The Other ◽  
Discourse Structure ◽  
Oral Narratives ◽  
Clear Cut ◽  
The Core ◽  
New Information ◽  
Intonation Units ◽  
Locative Expressions ◽  
Transitive Verbs

The analysis in this paper was based on five Malay narratives of the “frog story”. In these narratives, the types of lexical arguments and their relations with information flow and topic continuity were analyzed. It was found that most narrators used one lexical argument in telling the frog story (e.g., sarang itu jatuh “the nest fell”). About 60% of the verbs in the narratives contained one lexical argument only. Some transitive verbs that usually require the presence of both lexical arguments were used with one lexical argument only when produced in speech (e.g., dia mencari ø di merata tempat “he searched (for) ø everywhere”). Objects were sometimes omitted, as their meanings could be predicted from previous context. Despite the omission of objects, transitive constructions still prevailed in the stories. The most frequently occurring lexical arguments were objects (O) (37%), followed by intransitive subjects (S) (29%) and transitive subjects (A) (27%). In addition, our results showed that new information in Malay was usually allocated to the core argument of the object and to locative expressions, indicating that most of the new information appeared at the end of a clause. On the other hand, topic continuity was held between the subjects in two continuous intonation units. This clear-cut division of discourse functions in the heads and tails of constructions was consistently found in the five pieces of narration. This observation not only showed how ideas could be continued in Malay oral narratives, but also contributes to the study of discourse structure in Malay.

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