An Exhumation History of Continents over Billion-Year Time Scales

Science ◽  
2012 ◽  
Vol 335 (6064) ◽  
pp. 73-76 ◽  
Author(s):  
Terrence J. Blackburn ◽  
Samuel A. Bowring ◽  
J. Taylor Perron ◽  
Kevin H. Mahan ◽  
Francis O. Dudas ◽  
...  
Keyword(s):  
Time Scales ◽  
Continental Lithosphere ◽  
Geologic Time ◽  
Erosion Rates ◽  
Continuous Record ◽  
History Of ◽  
Lower Crustal ◽  
Insight Into ◽  
Exhumation History ◽  
Stable Structures

The continental lithosphere contains the oldest and most stable structures on Earth, where fragments of ancient material have eluded destruction by tectonic and surface processes operating over billions of years. Although present-day erosion of these remnants is slow, a record of how they have uplifted, eroded, and cooled over Earth’s history can provide insight into the physical properties of the continents and the forces operating to exhume them over geologic time. We constructed a continuous record of ancient lithosphere cooling with the use of uranium-lead (U-Pb) thermochronology on volcanically exhumed lower crustal fragments. Combining these measurements with thermal and Pb-diffusion models constrains the range of possible erosion histories. Measured U-Pb data are consistent with extremely low erosion rates persisting over time scales approaching the age of the continents themselves.

scholarly journals The lower crustal Dasu Tonalite and its implications for the formation reformation-exhumation history of the Kohistan arc crust

2008 ◽  
Vol 2 (4) ◽  
pp. 211 ◽  
Author(s):  
Takashi Nakajima ◽  
IS Williams ◽  
H Hyodo ◽  
K Miyasaka ◽  
Y Kono ◽  
...  
Keyword(s):  
History Of ◽  
Lower Crustal ◽  
Exhumation History

scholarly journals Time scale bias in erosion rates of glaciated landscapes

2016 ◽  
Vol 2 (10) ◽  
pp. e1600204 ◽  
Author(s):  
Vamsi Ganti ◽  
Christoph von Hagke ◽  
Dirk Scherler ◽  
Michael P. Lamb ◽  
Woodward W. Fischer ◽  
...  
Keyword(s):  
Time Scales ◽  
Time Scale ◽  
Erosion Rate ◽  
Earth Science ◽  
Geologic Time ◽  
Erosion Rates ◽  
River Incision ◽  
Tightly Coupled ◽  
Heavy Tailed ◽  
Averaging Time

Deciphering erosion rates over geologic time is fundamental for understanding the interplay between climate, tectonic, and erosional processes. Existing techniques integrate erosion over different time scales, and direct comparison of such rates is routinely done in earth science. On the basis of a global compilation, we show that erosion rate estimates in glaciated landscapes may be affected by a systematic averaging bias that produces higher estimated erosion rates toward the present, which do not reflect straightforward changes in erosion rates through time. This trend can result from a heavy-tailed distribution of erosional hiatuses (that is, time periods where no or relatively slow erosion occurs). We argue that such a distribution can result from the intermittency of erosional processes in glaciated landscapes that are tightly coupled to climate variability from decadal to millennial time scales. In contrast, we find no evidence for a time scale bias in spatially averaged erosion rates of landscapes dominated by river incision. We discuss the implications of our findings in the context of the proposed coupling between climate and tectonics, and interpreting erosion rate estimates with different averaging time scales through geologic time.

The Subaltern Speak- A Study On The Culture Of The Arunachalis With Special Reference To Mamang Dai’s The Legends Of Pensam

2019 ◽  
Vol 5 (4) ◽  
pp. 14-20
Author(s):  
Ms. Cheryl Antonette Dumenil ◽  
Dr. Cheryl Davis
Keyword(s):  
Special Reference ◽  
Small World ◽  
Natural World ◽  
Arunachal Pradesh ◽  
North East India ◽  
North East ◽  
Shared History ◽  
History Of ◽  
And Gender ◽  
Insight Into

North- East India is an under veiled region with an awe-inspiring landscape, different groups of ethnic people, their culture and heritage. Contemporary writers from this region aspire towards a vision outside the tapered ethnic channel, and they represent a shared history. In their writings, the cultural memory is showcased, and the intensity of feeling overflows the labour of technique and craft. Mamang Dai presents a rare glimpse into the ecology, culture, life of the tribal people and history of the land of the dawn-lit mountains, Arunachal Pradesh, through her novel The Legends of Pensam. The word ‘Pensam’ in the title means ‘in-between’,  but it may also be interpreted as ‘the hidden spaces of the heart’. This is a small world where anything can happen. Being adherents of the animistic faith, the tribes here believe in co-existence with the natural world along with the presence of spirits in their forests and rivers. This paper attempts to draw an insight into the culture and gender of the Arunachalis with special reference to The Legends of Pensam by Mamang Dai.

Collected Documents on the History of the Pskov Orthodox Mission: A Recent Publication

2018 ◽  
pp. 306-312
Author(s):  
Veniamin F. Zima ◽  
Keyword(s):  
Personal Data ◽  
Prisoners Of War ◽  
Inner Life ◽  
Great Patriotic War ◽  
Occupied Territories ◽  
History Of ◽  
Underground Resistance ◽  
The Baltic ◽  
The Church ◽  
Insight Into

The reviewed work is devoted to a significant, and yet little-studied in both national and foreign scholarship, issue of the clergy interactions with German occupational authorities on the territory of the USSR in the days of the Great Patriotic War. It introduces into scientific use historically significant complex of documents (1941-1945) from the archive of the Office of the Metropolitan Sergius (Voskresensky) of Vilnius and Lithuania, patriarchal exarch in Latvia and Estonia, and also records from the investigatory records on charges against clergy and employees concerned in the activities of the Pskov Orthodox Mission (1944-1990). Documents included in the publication are stored in the archives of Moscow, St. Petersburg, Estonia, Lithuania, Leningrad, Novgorod, and Pskov regions. They allow some insight into nature, forms, and methods of the Nazi occupational regime policies in the conquered territories (including policies towards the Church). The documents capture religious policies of the Nazis and inner life of the exarchate, describe actual situation of population and clergy, management activities and counterinsurgency on the occupied territories. The documents bring to light connections between the exarchate and German counterintelligence and reveal the nature of political police work with informants. They capture the political mood of population and prisoners of war. There is information on participants of partisan movement and underground resistance, on communication net between the patriarchal exarchate in the Baltic states and the German counterintelligence. Reports and dispatches of the clergy in the pay of the Nazis addressed to the Metropolitan Sergius (Voskresensky) contain detailed activity reports. Investigatory records contain important biographical information and personal data on the collaborators. Most of the documents, being classified, have never been published before.

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