Emerald: Title Detail: Advances in Accounting Behavioral Research by Khondkar E. Karim
Username: Password:. WRF Conference. Register Forgot Password? We would like to ask you for a moment of your time to fill in a short questionnaire, at the end of your visit. If you decide to participate, a new browser tab will open so you can complete the survey after you have completed your visit to this website. Thanks in advance for your time. Skip to content.
Conference Alerts Thailand 12222,2020
Search for books, journals or webpages All Pages Books Journals. Editors: Philip Reckers. Hardcover ISBN: Imprint: JAI Press. Published Date: 8th May At lower elevation forests with moist soil conditions, large Alaska yellow cedar trees can co-dominate with hemlock and spruce beginning a few centuries after disturbance Harris et al. The ring widths of long-lived yellow cedar, spruce, and hemlock trees can be sensitive to interannual variations in air temperatures, which facilitates the cross-dating of sub-fossil logs Barclay et al.
La Perouse described and mapped the glaciers in the coastal St. Elias Mountains and Lituya Bay, the Malaspina expedition mapped and observed the coastline and glaciers in the ice-choked Yakutat Bay while searching in vain for the Northwest Passage, and Vancouver charted Cross Sound Figure 1.
Approximately a century after these first European explorers, the Harriman expedition Gilbert, ; Burroughs and Muir, , and the Boundary Commission of the United States and Canada provided observations and maps of glacier extent during the late 19 th and earliest 20th century 1 , including detailed observations of La Perouse Glacier.
These early observations are summarized by Tebenkov ; Davidson , and Tarr and Martin and allow us to compare the extents of glaciers in the late 18th century with their extents and years later. While exploring the La Perouse forefield in May of , we discovered an ancient forest recently exposed by the retreating margin of the glacier Figure 2. We collected tree cores to determine when these trees began growing and when they died in order to infer the limiting ages of glacier retreat and advance.
We identified the different tree genera based on bark characteristics, stem and branch habit, and wood aroma. Two tree cores 0. Radiocarbon 14 C samples were collected from the bark of one tree to constrain the timing of tree death, and two other 14 C samples were collected from the base of buried soil organic horizons located 50 m from one another in order to provide minimum dates on the initiation of soil development following the penultimate glacier retreat.
Radiocarbon samples were analyzed by accelerator mass spectrometry at Beta Analytic in Miami, Florida, and then calibrated to calendar years using the IntCal13 curve Reimer et al. Tree cores were sanded with progressively finer sand paper from to grit to reveal ring boundaries. Ring widths were measured either manually to 0. Ring-width series were visually and statistically cross-dated using standard dendrochronological techniques Holmes, ; Stokes and Smiley, We developed two ring-width chronologies from the exhumed forest at the La Perouse Glacier.
The individual tree-ring series from the buried forest were cross-dated with previously measured, calendar-dated chronologies from the GOA region Figure 1 ; Wiles et al. Cross-dated individual series were combined to develop master, calendar-dated chronologies based on the mean, standardized ring-width of all tree-ring series following detrending using a 32 year high-pass spline filter Holmes, Correlations between the newly dated La Perouse cedar and hemlock—spruce chronologies and master chronologies from elsewhere in the GOA region Wiles et al.
We also compared the La Perouse chronologies with a ring-width chronology derived from trees killed by the rising waters of an ice-dammed lake along the margin of the Brady Glacier, 36 km to southeast of the La Perouse exhumed forest Figure 1 ; Capps et al. Hundreds of in situ dead trees have been exhumed from kame-terrace gravels over the last decade by an ice-marginal stream adjacent to the retreating margin of the La Perouse Glacier Figures 1 , 2.
This exhumed forest is devoid of living plant tissue but exquisitely well-preserved, probably due to its rapid burial by sand and gravel, which then shielded it from the overriding glacial ice. The exhumed forest contains trees that retained bark and delicate branches, tree saplings, and shrubs, many of which are still rooted in moss-covered soils Figure 2. The exhumed trees are uniformly bent and sheared off 5—10 m above their root crowns, leaving flags of shattered wood oriented westward in the direction of glacier flow Figure 2.
No adventitious roots were found on hemlock or spruce stems, which can occur in these taxa when they are rooted in a gradually aggrading surface Zobel and Antos, This suggests that none of these exhumed trees survived initial burial. The younger date is likely the minimum-limiting age for the penultimate retreat of the La Perouse Glacier, after which the exhumed forest began growth. The older date probably represents an older, inter-stadial soil that was covered in till and is now exposed below the forest soil.
The floating ring-width chronologies from the exhumed forest consist of 49 individual ring-width time series from 30 trees 31 series from 20 hemlock—spruce trees and 18 series from 10 cedar trees Figure 3. The inter-series correlations within the cedar and hemlock—spruce chronologies are 0.
After shifting the floating cedar chronology in order to obtain peak correlations with the calendar-dated cedar chronologies based on living trees Wiles et al. Peak hemlock—spruce correlations between the calendar-dated, living-tree chronology and the floating, exhumed-forest chronology are 0. After anchoring the floating chronologies to calendar years, the cross-dated chronologies from exhumed trees span the calendar years CE — and CE — for cedar and hemlock—spruce, respectively Figure 4.
The oldest cross-dated hemlock and cedar rings are CE and CE , respectively, and at least several centuries of post-glacial forest succession is typically required in Southeast Alaska for this forest type to assemble itself Harris et al. Figure 3. Master ring-width chronology of the La Perouse western hemlock and Sitka spruce trees gray; bottom compared with the master chronology of living hemlock and spruce blue; top from the Gulf of Alaska region Wiles et al.
Advances in Accounting, Volume 19
Figure 4. Segment plot of crossdated tree-ring series from the exhumed forest at the La Perouse Glacier and from the nearby Brady Glacier Figure 1 ; Capps et al. The calendar ages of the outer rings correspond to the approach of the La Perouse Glacier and its ice-marginal outwash stream. The trees died after being buried by outwash gravel. Also noted are when the La Perouse Glacier reached its LIA moraine in as related to the Harriman Expedition by the US Fish Commission Burroughs and Muir, , and the earliest age of spruce that colonized that moraine indicating glacier retreat.
In summary, the earliest calendar-dated ring CE represents the earliest date of forest establishment at this site, and indicates the minimum-limiting age for the penultimate retreat of the La Perouse Glacier, after which the exhumed forest began growth. As indicated by the assigned calendar age on the outermost rings, 20 of the 30 cross-dated trees died when glacial outwash buried them between CE and Figure 4.
Establishment of spruce in this recently deglaciated location i. In support of this inference, we have observed spruce seedlings colonizing the La Perouse foreland gravels in areas that were glaciated 5—10 years prior. Several, rapid glacier fluctuations have occurred since , including short-lived re-advances around CE Tarr and Martin, and CE Seitz, , but the glacier has mostly been in retreat for the last several decades.
In summary, after being in a retracted state relative to its position since at least CE , based on the cross-dated tree-ring chronology, the La Perouse Glacier was advancing to near its position between and based on the outer rings of most trees sampled from the buried forest.
The glacier reached its LIA maximum position ca. Sometime between CE and based on pith ages of spruce colonizing the LIA moraine , the glacier began a major retreat, and subsequent fluctuations never caused the ice margin to reach the LIA moraine again Table 1 and Figure 4. But what do these glacier fluctuations signify in terms of paleoclimate?
- I Poeti Contemporanei 87 - 7 autori (I Poeti Contemporanei - 7 autori) (Italian Edition).
- Concurring Opinion Writing on the U.S. Supreme Court (SUNY series in American Constitutionalism)!
- Related eJournals.
- Call for Papers?
- Original Research ARTICLE.
- Milenium: vzrivenata vazdushna kula | МИЛЕНИУМ: Взривената въздушна кула (Съвременна литература | Криминална и трилъри);
- The British Empire: Pomp, Power and Postcolonialism (History Insights).
It is possible that these recent fluctuations of the La Perouse Glacier were driven by internal glacier dynamics rather than climate Van der Veen, For example, if the glacier had retreated up its fjord to a point where it terminated on land, a subsequent advance could have occurred regardless of climate. In the aftermath of a catastrophic calving retreat, this situation can result in extremely positive mass balance, which can then cause the terminus to advance, provided a terminal moraine shoal is accumulating in front of the glacier to protect it from iceberg calving Mann, ; Post et al.
A non-climatically driven scenario like this is the null hypothesis when seeking linkages between climate and the fluctuations of glaciers like La Perouse that at times had calving fronts.
- The Fastest Growing Religion on Earth: How Genealogy Captured the Brains and Imaginations of Americans.
- The Cambridge Companion to Thomas Pynchon (Cambridge Companions to Literature).
- Short and Simple Guide To Smart Investing.
- Monster in the Kitchen.
- Regulators and Effectors of Small GTPases: Rho Family: 406 (Methods in Enzymology).
- For The Love Of Our West Coast.
- You might also be interested in...
Finding synchronized glacier advances throughout the GOA region in the s would indicate these changes were indeed climatically driven. Because we are surveying the behavior of different glaciers on the century scale — , the variability of glacier response times on shorter time scales should have relatively minor effects for these high-throughput and relatively small glaciers whose response times to climate are on the order of several decades Oerlemans and Fortuin, Below we review historical observations and tree-ring dating that constrain the fluctuations of other glaciers draining the St.
Corroborating the oral tradition of local Native people Topham, , Barclay et al. Belcher describes the Icy Bay glacier terminus in CE as a 9-m-high ice cliff located near the present mouth of the bay.
Several minor retreats occurred within this period, and the glacier filling Icy Bay probably reached its maximum extent sometime between CE and Post and Plfaker, unpublished. Recession from the late LIA maximum began between CE and Tarr and Martin, and has continued with great rapidity up to the present day Figure 5a. Figure 5. Maps of individual bays and glaciers discussed in the text showing LIA termini positions.
Glacier Bay is located immediately to the east of this map. This glacier is now near its maximum Holocene extent, which means that most evidences of its former fluctuations are concealed beneath it Though see next section. Minor advances and retreats have occurred within the historical period Topham, ; Russell, ; Tarr and Martin, For example, Tebenkov compiled maps of the coastline bordering the Malaspina Glacier based on the reports and charts of Russian explorers who visited the area between and In summary, after reaching its current extended position sometime prior to , the Malaspina Glacier has experienced a series of minor advances and retreats with a significant advance at least along a portion of its wide perimeter during the s.
CE Barclay et al. This advance — probably representing coeval advances by both the Malaspina and Hubbard Glaciers — reached its maximum extent at the mouth of Yakutat Bay Figure 5b , where its calving terminus deposited an arcuate shoal across the fjord mouth. Retreat from this most recent LIA maximum was underway by CE , based on the age of a tree growing in outer Yakutat Bay and the 14 C ages of basal organics in kettle ponds there Barclay et al.
Archeological sites in outer Yakutat Bay date between CE and and are consistent with this area being deglaciated during this period Crowell, , written communication.
Related Advances in Accounting: 19
Copyright 2019 - All Right Reserved