Sea Level Change in the Western James Bay Region of Subarctic Ontario: Emergent Land and Implications for Treaty No. 9

In 1905 and 1906, the Cree of the southwestern James Bay region signed Treaty No. 9 whereby they relinquished to the Canadian government their claim to the lands south of the Albany River (the northern boundary of the province of Ontario at the time). The official text of Treaty No. 9 made no mention of land submerged below water cover, and thus the Cree did not relinquish such regions at that time. By contrast, the Cree of the northwestern James Bay and southwestern Hudson Bay region who signed the 1929–30 Adhesions to Treaty No. 9 relinquished their claims to “land covered by water” for the area bounded on the south by the northerly limit of Treaty No. 9, as this clause was specifically included in the text of the adhesion. The issue of “land covered by water” is significant because the western James Bay region has been, and will continue to be, subject to sea level changes associated with ongoing adjustments due to the last ice age and modern global warming signals. In the absence of detailed maps, we used models of these processes, constrained by available geophysical and geodetic data sets, to retrodict shoreline changes and the rate of land emergence over the last two centuries within the boundaries specified by Treaty No. 9. We also project shoreline migration to the end of the 21st century within the same region. The rate of land emergence since 1905 in the area south of the Albany River is estimated as ~3.0 km2/yr. Over the next century, land will continue to emerge in this region at a mean rate of ~1.4 km2/yr. This emergent land should be a subject of consideration within any comprehensive land claim put forward by the Cree; in this regard, it will be interesting to see how the Canadian judicial system and the Comprehensive Claims Branch handle the novel issue of emergent land.En 1905 et 1906, les Cris du sud-ouest de la région de la baie James ont signé le Traité no 9, par le biais duquel ils ont cédé au gouvernement du Canada leur droit de revendication des terres au sud de la rivière Albany (la limite nord de la province de l’Ontario à l’époque). Le texte officiel du Traité no 9 ne faisait aucune mention des terres submergées sous l’eau, si bien que les Cris n’ont pas renoncé à ces régions à ce moment-là. En revanche, les Cris du nord-ouest de la baie James et du sud-ouest de la baie d’Hudson qui ont signé les adhésions au Traité no 9 (1929-1930) ont renoncé à leurs revendications aux « terres recouvertes d’eau » dans la zone délimitée au sud par la limite nord du Traité no 9, puisque cette clause était expressément incluse dans le texte de l’adhésion. La question des « terres recouvertes d’eau » est importante parce que l’ouest de la région de la baie James a été et continuera d’être assujettie aux variations du niveau de la mer liées aux ajustements continus découlant de la dernière période glaciaire et des récents signes de réchauffement planétaire. En l’absence de cartes détaillées, nous avons utilisé des modèles de ces processus, limités par les ensembles de données géophysiques et géodésiques disponibles, pour déterminer de façon rétrospective les changements du littoral et le taux d’émergence des terres au cours des deux derniers siècles dans les limites précisées dans le Traité no 9. Nous faisons également une projection de la migration du littoral jusqu’à la fin du XXIe siècle dans cette même région. Le taux d’émergence des terres depuis 1905 dans la région au sud de la rivière Albany est estimé à ~3,0 km2/année. Au cours du prochain siècle, les terres continueront d’émerger dans cette région au taux moyen de ~1,4 km2/année. Ces terres émergées devraient être prises en compte dans toute revendication territoriale globale présentée par les Cris. À cet égard, il sera intéressant de voir comment le système judiciaire canadien et la Direction générale des revendications globales traiteront cette nouvelle question des terres émergées

Time-dependent rotational stability of dynamic planets with elastic lithospheres

True polar wander (TPW), a reorientation of the rotation axis relative to the solid body, is driven by mass redistribution on the surface or within the planet and is stabilized by two aspects of the planet's viscoelastic response: the delayed viscous readjustment of the rotational bulge and the elastic stresses in the lithosphere. The latter, following Willemann (1984), is known as remnant bulge stabilization. In the absence of a remnant bulge, the rotation of a terrestrial planet is said to be inherently unstable. Theoretical treatments have been developed to treat the final (equilibrium) state in this case and the time-dependent TPW toward this state, including nonlinear approaches that assume slow changes in the inertia tensor. Moreover, remnant bulge stabilization has been incorporated into both equilibrium and linearized, time-dependent treatments of rotational stability. We extend the work of Ricard et al. (1993) to derive a nonlinear, time-dependent theory of TPW that incorporates stabilization by both the remnant bulge and viscous readjustment of the rotational bulge. We illustrate the theory using idealized surface loading scenarios applied to models of both Earth and Mars. We demonstrate that the inclusion of remnant bulge stabilization reduces both the amplitude and timescale of TPW relative to calculations in which this stabilization is omitted. Furthermore, given current estimates of mantle viscosity for both planets, our calculations indicate that departures from the equilibrium orientation of the rotation axis in response to forcings with timescale of 1 Myr or greater are significant for Earth but negligible for Mars

Regional seismic wave propagation (Lg and Sn) and Pn attenuation in the Arabian Plate and surrounding regions

An edited version of this paper was published by Blackwell Publishing. Copyright 2004, Blackwell Publishing. See also: http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-246X.2004.02246.x; http://atlas.geo.cornell.edu/MiddleEastNorthAfrica/publications/Al-Damegh2004.htmContinuous recordings of 17 broadband and short period digital seismic stations from a newly established seismological network in Saudi Arabia, along with digital recordings from the broadband stations of the GSN, MEDNET, GEOFON, a temporary array in Saudi Arabia, and a temporary short period stations in Oman, were analyzed to study the lithospheric structure of the Arabian plate and surrounding regions. The Arabian plate is surrounded by a variety of types of plate boundaries: continental collision (Zagros belt and Bitlis suture), continental transform (Dead Sea fault system), young sea floor spreading (Red Sea and Gulf of Aden), and oceanic transform (Owen fracture zone). Also, there are many intraplate Cenozoic processes such as volcanic eruptions, faulting, and folding that are taking place. We used this massive waveform database of more than 6200 regional seismogram to map zones of blockage, inefficient, and efficient propagation of the Lg and Sn phases in the Middle East and East Africa. We observed Lg blockage across the Bitlis suture and Zagros fold and thrust belt, corresponding to the boundary between the Arabian and Eurasian plates. This is probably due to a major lateral change in the Lg crustal wave-guide. We also observed inefficient Lg propagation along the Oman mountains. Blockage and inefficient Sn propagation is observed along and for a considerable distance to the east of the Dead Sea fault system and in the northern portion of the Arabian plate (south of the Bitlis suture). These mapped zones of high Sn attenuation, moreover, closely coincide with extensive Neogene and Quaternary volcanic activity. We have also carefully mapped the boundaries of the Sn blockage within the Turkish and Iranian plateaus. Furthermore, we observed Sn blockage across the Owen fracture zone and across some segments of the Red Sea. These regions of high Sn attenuation most probably have anomalously hot and possibly thin lithospheric mantle (i.e., mantle lid). A surprising result is the efficient propagation of Sn across a segment of the Red Sea; an indication that active sea floor spreading is not continuous along the axis of the Red Sea. We also investigated the attenuation of Pn phase (QPn) for 1-2 Hz along the Red Sea, Dead Sea fault system, within the Arabian shield, and in the Arabian platform. Consistent with the Sn attenuation, we observed low QPn values of 22 and 15 along the western coast of the Arabian plate and along the Dead Sea fault system, respectively, for a frequency of 1.5 Hz. Higher QPn values on the order of 400 were observed within the Arabian shield and platform for the same frequency. Our results based on Sn and Pn observations along the western and northern portions of the Arabian plate imply the presence of a major anomalously hot and thinned lithosphere in these regions that may be caused by the extensive upper mantle anomaly that appears to span most of east Africa and western Arabia

Crustal structure of the Arabian Plate: New constraints from the analysis of teleseismic receiver functions

An edited version of this paper was published by Elsevier Science. Copyright 2005, Elsevier Science. See also: http://dx.doi.org/10.1016/j.epsl.2004.12.020; http://atlas.geo.cornell.edu/SaudiArabia/publications/Al-Damegh%202005.htmReceiver functions for numerous teleseismic earthquakes recorded at 23 broadband and mid-band stations in Saudi Arabia and Jordan were analyzed to map crustal thickness within and around the Arabian plate. We used spectral division as well as time domain deconvolution to compute the individual receiver functions and receiver function stacks. The receiver functions were then stacked using the slant stacking approach to estimate Moho depths and Vp/Vs for each station. The errors in the slant stacking were estimated using a bootstrap re-sampling technique. We also employed a grid search waveform modeling technique to estimate the crustal velocity structure for seven stations. A jackknife re-sampling approach was used to estimate errors in the grid search results for three stations. In addition to our results, we have also included published receiver function results from two temporary networks in the Arabian shield and Oman as well as three permanent GSN stations in the region. The average crustal thickness of the late Proterozoic Arabian shield is 39 km. The crust thins to about 23 km along the Red Sea coast and to about 25 km along the margin of the Gulf of Aqaba. In the northern part of the Arabian platform, the crust varies from 33 to 37 km thick. However, the crust is thicker (41?53 km) in the southeastern part of the platform. There is a dramatic change in crustal thickness between the topographic escarpment of the Arabian shield and the shorelines of the Red Sea. We compared our results in the Arabian shield to nine other Proterozoic and Archean shields that include reasonably well determined Moho depths, mostly based on receiver functions. The average crustal thickness for all shields is 39 km, while the average for Proterozoic shields is 40 km, and the average for Archean shields is 38 km. We found the crustal thickness of Proterozoic shields to vary between 33 and 44 km, while Archean shields vary between 32 and 47 km. Overall, we do not observe a significant difference between Proterozoic and Archean crustal thickness. We observed a dramatic change in crustal thickness along the Red Sea margin that occurs over a very short distance. We projected our results over a cross-section extending from the Red Sea ridge to the shield escarpment and contrasted it with a typical Atlantic margin. The transition from oceanic to continental crust of the Red Sea margin occurs over a distance of about 250 km, while the transition along a typical portion of the western Atlantic margin occurs at a distance of about 450 km. This important new observation highlights the abruptness of the breakup of Arabia. We argue that a preexisting zone of weakness coupled with anomalously hot upper mantle could have initiated and expedited the breakup

抗腫瘍性トロポロン誘導体の創製と作用機序に関する研究

We image the lithospheric and upper asthenospheric structure of western continental Yemen with 24 broadband stations to evaluate the role of the Afar plume on the evolution of the continental margin and its extent eastward along the Gulf of Aden. We use teleseismic tomography to compute relative P wave velocity variations in south-western Yemen down to 300 km depth. Published receiver function analysis suggest a dramatic and localized thinning of the crust in the vicinity of the Red Sea and the Gulf of Aden, consistent with the velocity structure that we retrieve in our model. The mantle part of the model is dominated by the presence of a low-velocity anomaly in which we infer partial melting just below thick Oligocene flood basalts and recent off-axis volcanic events (from 15 Ma to present). This low-velocity anomaly could correspond to an abnormally hot mantle and could be responsible for dynamic topography and recent magmatism in western Yemen. Our new P wave velocity model beneath western Yemen suggests the young rift flank volcanoes beneath margins and on the flanks of the Red Sea rift are caused by focused small-scale diapiric upwelling from a broad region of hot mantle beneath the area. Our work shows that relatively hot mantle, along with partial melting of the mantle, can persist beneath rifted margins after breakup has occurred

Tectonic events, continental intraplate volcanism, and mantle plume activity in northern Arabia: constraints form geochemistry and Ar-Ar dating of Syrian lavas

New (40)Ar/(39)Ar ages combined with chemical and Sr, Nd, and Pb isotope data for volcanic rocks from Syria along with published data of Syrian and Arabian lavas constrain the spatiotemporal evolution of volcanism, melting regime, and magmatic sources contributing to the volcanic activity in northern Arabia. Several volcanic phases occurred in different parts of Syria in the last 20 Ma that partly correlate with different tectonic events like displacements along the Dead Sea Fault system or slab break-off beneath the Bitlis suture zone, although the large volume of magmas and their composition suggest that hot mantle material caused volcanism. Low Ce/Pb (<20), Nb/Th (<10), and Sr, Nd, and Pb isotope variations of Syrian lavas indicate the role of crustal contamination in magma genesis, and contamination of magmas with up to 30% of continental crustal material can explain their (87)Sr/(86)Sr. Fractionation-corrected major element compositions and REE ratios of uncontaminated lavas suggest a pressure-controlled melting regime in western Arabia that varies from shallow and high-degree melt formation in the south to increasingly deeper regions and lower extents of the beginning melting process northward. Temperature estimates of calculated primary, crustally uncontaminated Arabian lavas indicate their formation at elevated mantle temperatures (T(excess) similar to 100-200 degrees C) being characteristic for their generation in a plume mantle region. The Sr, Nd, and Pb isotope systematic of crustally uncontaminated Syrian lavas reveal a sublithospheric and a mantle plume source involvement in their formation, whereas a (hydrous) lithospheric origin of lavas can be excluded on the basis of negative correlations between Ba/La and K/La. The characteristically high (206)Pb/(204)Pb (similar to 19.5) of the mantle plume source can be explained by material entrainment associated with the Afar mantle plume. The Syrian volcanic rocks are generally younger than lavas from the southern Afro-Arabian region, indicating a northward progression of the commencing volcanism since the arrival of the Afar mantle plume beneath Ethiopia/Djibouti some 30 Ma ago. The distribution of crustally uncontaminated high (206)Pb/(204)Pb lavas in Arabia indicates a spatial influence of the Afar plume of similar to 2600 km in northward direction with an estimated flow velocity of plume material on the order of 22 cm/a

Dynamic topography of continents and rotational stability of planets with lithospheres

This thesis examines two distinct topics related to the long-term evolution of terrestrial planets. The first, dynamic topography, is the vertical motion of the Earth’s tectonic plates in response to viscous stresses in the mantle driven by connective processes. Using mantle flow modelling, I show how dynamic topography linked to plate subduction can explain a long-wavelength component of sediment deposition in the Silurian Baltic Basin. Simulations constrain the paleo-dip angle of subuction to 40-60 degrees and show that the slab-induced mantle flow mechanism provides 40-85% of the near-field sediment deposition. In another regional study, I use convection simulations constrained by seisemic tomography to reconcile the observed broad tilting of the present-day Arabian platform that extends from the Red Sea to the Persian Gulf. This area has been cited as a classic example of rift-flank uplift; however the influence of the rift-flank processes is largely limited to uplift within a few hundred kilometers of the margin. Density heterogeneities linked to a megaplume, which are responsible for high topography in Southern Africa and rifting in East Africa, can reconcile the anomalous topography seen in Arabia. The second topic in this thesis deals with the rotational stability of planets with lithospheres. Using an equilibrium rotational theory suitable for a planet with a lithosphere characterized by long-term elastic strength, along with observational constraints on the figure of Mars, I show that the current rotation axis of Mars is stable. I also find that development of the massive Tharsis volcanic province cause a reorientation of the planet that was likely less than 15 degrees and that the thickness of the elastic lithosphere at the time of Tharsis formation was at least ~ 50km. Finally, I extend the equilibrium theory for a planet with an elastic lithosphere to consider the effect of a viscoelastic lithosphere on rotational stability. I find that the sufficiently high lithospheric viscosities (5x10(24) Pa-s of greater) a viscoelastic lithosphere can have a significant impact on reducing rates of true polar wander induced by an uncompensated load. These rates depend on the viscosity of the lithosphere and the size of the load.Ph.D

Identification of a putative transcription factor gene (WBSCR11) that is commonly deleted in Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a complex developmental disorder involving the hemizygous deletion of genes on chromosome 7q11.23. The cardiovascular aspects of the disorder are known to be caused by haploinsufficiency for ELN, but the genes contributing to the other features of WBS are still undetermined. Fifteen genes have been shown to reside within the WBS deletion, and here we report the identification and cloning of an additional gene that is commonly deleted. WBSCR11, which was identified through genomic DNA sequence analysis and cDNA library screening, was positioned toward the telomeric end of the WBS deletion. The gene is expressed in all adult tissues analyzed, including many regions of the brain. The predicted protein displays hemology to another gene from the WBS deletion, GTF2I, which is known to be a transcription factor. We postulate that WBSCR11 is also a transcription factor and may contribute to the spectrum of developmental symptoms found in WBS.link_to_subscribed_fulltex

Media 1: Phase-gradient contrast in thick tissue with a scanning microscope

Originally published in Biomedical Optics Express on 01 February 2014 (boe-5-2-407