Re-Os isotope evidence for late Archaean.stabilisation of a thick lithospheric mantle keel beneath the Kirkland Lake area, Superior province, Canada. Further evidence for long-term crust-mantle cuopling

2019 ◽  
Keyword(s):  
Lithospheric Mantle ◽  
Superior Province ◽  
Lake Area ◽  
Isotope Evidence ◽  
Os Isotope

Re-Os isotope characteristics of postorogenic lavas: Implications for the nature of young lithospheric mantle and its contribution to basaltic magmas

Geology ◽  
2000 ◽  
Vol 28 (6) ◽  
pp. 563-566 ◽  
Author(s):  
Bruce F. Schaefer ◽  
Simon P. Turner ◽  
Nick W. Rogers ◽  
Chris J. Hawkesworth ◽  
Helen M. Williams ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Basaltic Magmas ◽  
Os Isotope

scholarly journals Growth of a high-elevation large inland lake, associated with climate change and permafrost degradation in Tibet

2010 ◽  
Vol 14 (3) ◽  
pp. 481-489 ◽  
Author(s):  
J. Liu ◽  
S. Kang ◽  
T. Gong ◽  
A. Lu
Keyword(s):  
High Elevation ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
The Tibetan Plateau ◽  
Permafrost Degradation ◽  
Lake Area ◽  
Pan Evaporation ◽  
Precipitation Increase ◽  
Nam Co Lake

Abstract. This study analyzed satellite images and long term climate variables from a high-elevation meteorological station (4730 m) and streamflow records to examine hydrological response of Nam Co Lake (4718 m), the largest lake on the Tibetan Plateau, over the last 50 years. The results show the lake area extended by 51.8 km2 (2.7% of the total area) when compared with the area in 1976. This change is associated with an annual precipitation increase of 65 mm (18.6%), annual and winter mean temperature increases of 0.9 °C and 2.1 °C respectively, an annual runoff increase of 20% and an annual pan evaporation decrease of about 2%, during the past 20 years. The year of the change point in annual precipitation, air temperature, annual pan evaporation and runoff occurred in 1971, 1983, 1997 and 1997, respectively. The timing of the lake growth corresponds with the abrupt increase in annual precipitation and runoff since the mid-1990s.

scholarly journals Scaling property of ideal granitic sequences

2007 ◽  
Vol 14 (3) ◽  
pp. 237-246 ◽  
Author(s):  
D. Xu ◽  
Q. Cheng ◽  
F. Agterberg
Keyword(s):  
Lake Area ◽  
Fine Grained ◽  
Multi Scale ◽  
Invariance Properties ◽  
The Past ◽  
Ideal Granite ◽  
Markov Properties ◽  
The Ideal

Abstract. Quantification of granite textures and structures using a mathematical model for characterization of granites has been a long-term attempt of mathematical geologists over the past four decades. It is usually difficult to determine the influence of magma properties on mineral crystallization forming fined-grained granites due to its irregular and fine-grained textures. The ideal granite model was originally developed for modeling mineral sequences from first and second-order Markov properties. This paper proposes a new model for quantifying scale invariance properties of mineral clusters and voids observed within mineral sequences. Sequences of the minerals plagioclase, quartz and orthoclase observed under the microscope for 104 aplite samples collected from the Meech Lake area, Gatineau Park, Québec were used for validation of the model. The results show that the multi-scale approaches proposed in this paper may enable quantification of the nature of the randomness of mineral grain distributions. This, in turn, may be related to original properties of the magma.

New Insights into Archean Crustal Development from Geochronology in the Rainy Lake Area, Superior Province, Canada

1989 ◽  
Vol 97 (4) ◽  
pp. 379-398 ◽  
Author(s):  
D. W. Davis ◽  
K. H. Poulsen ◽  
S. L. Kamo
Keyword(s):  
Superior Province ◽  
Lake Area

scholarly journals Snow distribution over the Namco lake area of the Tibetan Plateau

2009 ◽  
Vol 13 (11) ◽  
pp. 2023-2030 ◽  
Author(s):  
M. Li ◽  
Y. Ma ◽  
Z. Hu ◽  
H. Ishikawa ◽  
Y. Oku
Keyword(s):  
Tibetan Plateau ◽  
The Tibetan Plateau ◽  
Lake Area ◽  
State Variable ◽  
Nested Grids ◽  
Snow Distribution ◽  
Surface Skin Temperature ◽  
Modified Surface ◽  
Meteorological Observations

Abstract. The mesoscale snow distribution over the Namco lake area of the Tibetan Plateau on October 2005 has been investigated in this paper. The base and revised experiments were conducted using the Weather Research Model (WRF) with three nested grids that included a 1 km finest grid centered on the Namco station. Our simulation ran from 6 October through to 10 October 2005, which was concurrent with long term meteorological observations. Evaluation against boundary layer meteorological tower measurements and flux observations showed that the model captured the observed 2 m temperature and 10 m winds reasonably well in the revised experiment. The results suggest that output snow depth maximum amounts from two simulated experiments were centered downwind of the Namco lakeshore. Modified surface state variable, for example, surface skin temperature on the lake help to increase simulated credibility.

ReOs, SmNd, and RbSr isotope evidence for thick Archaean lithospheric mantle beneath the Siberian craton modified by multistage metasomatism

1995 ◽  
Vol 59 (5) ◽  
pp. 959-977 ◽  
Author(s):  
D.G. Pearson ◽  
S.B. Shirey ◽  
R.W. Carlson ◽  
F.R. Boyd ◽  
N.P. Pokhilenko ◽  
...  
Keyword(s):  
Siberian Craton ◽  
Lithospheric Mantle ◽  
Sr Isotope ◽  
Isotope Evidence

Middle Holocene Fishing and Hunting in the Baikal Region of Siberia

2015 ◽  
Author(s):  
Robert S. Losey ◽  
M. Anne Katzenberg ◽  
Tatiana Nomokonova
Keyword(s):  
Baikal Region ◽  
Faunal Remains ◽  
Regional Variability ◽  
Middle Holocene ◽  
Long Term Stability ◽  
Terrestrial Mammals ◽  
Isotope Evidence ◽  
Isotope Studies ◽  
Potential Food

This chapter shows how a combination of zooarchaeological and stable isotope evidence documents substantial but variable use of aquatic resources by Middle Holocene foragers inhabiting the Cis-Baikal region of Eastern Siberia. We first outline potential food items—including terrestrial mammals, riverine and lacustrine fish, the Baikal freshwater seal, and some plant foods. Faunal remains exist from both habitation sites and cemeteries. Habitation site assemblages show subsistence practices at seasonally occupied locations, with composition varying within the region. Some cemetery assemblages are taxonomically richer, indicating that small mammals and waterfowl were also important. Stable nitrogen and carbon isotope studies of human skeletal collections document substantial use of aquatic foods. Regional variability in the use of aquatic foods is evident, but there is little clear evidence for Middle Holocene dietary shifts. Instead, there appears to have been long-term stability with some regional variation related to resource availability.

Geochemistry and age of Timiskaming alkali volcanics and the Otto syenite stock, Abitibi, Ontario

1990 ◽  
Vol 27 (10) ◽  
pp. 1304-1311 ◽  
Author(s):  
D. Ben Othman ◽  
N. T. Arndt ◽  
W. M. White ◽  
K. P. Jochum
Keyword(s):  
Volcanic Rocks ◽  
Lake Area ◽  
Incompatible Elements ◽  
Ion Probe ◽  
Mineral Isochron

Tephrites and trachytes of the Timiskaming volcanics from the Kirkland Lake area (Ontario) and syenites and a granite from the nearby Otto Stock are characterized by extreme enrichment of incompatible elements coupled with relative depletion of Nb, Ti, and to a lesser extent Zr and Y.The volcanic rocks have a whole-rock Sm–Nd isochron age of 2740 ± 117 Ma (2σ error), and minerals separated from the Otto Stock, a Sm–Nd age of 2544 ± 50 Ma. Conventional and ion probe U–Pb analyses of zircons from the Otto Stock yielded an upper intercept age of 2700 ± 19 Ma, whereas the more concordant ion probe analyses had a mean 207Pb/206Pb age of 2671 ± 8 Ma (2σ). The latter is interpreted as the age of emplacement of both the volcanics and the pluton, and the Sm–Nd mineral isochron age is thought to reflect a period of later disturbance, probably during regional metamorphism.A high initial εNd of 2.5 ± 1.5 for Kirkland Lake volcanics indicates long-term isotopic depletion of their source. This value is the same as that for volcanic rocks throughout the Abitibi belt and indicates that any chemically enriched material in the source cannot have been much older than the volcanics themselves. An environment remote from older continents is inferred.

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