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Investigating Tectonism-Erosion-Climate-Couplings

Final Report Summary - ITECC (Investigating Tectonism-Erosion-Climate-Couplings)

Tectonics and climate are interdependent. The tectonics of orogens are moderated by climate through erosion. Exposure of rock by tectonics or erosion is critical to the feedback which governs changes in global climate, whilst topography influences rainfall. The principle objective of iTECC is to use the Himalaya as a natural laboratory to train young scientists in understanding such coupled processes. iTECC will integrate information from sedimentary archives with work on present-day processes: tectonics, weathering, erosion and climate. Hereto, iTECC brings together and develops expertise in observation and modeling of the active deformation of the lithosphere; processes of weathering and erosion; study of geological records of the past evolution of these processes; and modeling of present and past climate change. The breadth of this research provides training in observational, analytical and mathematical methods applied in the Earth and environmental sciences.
The proposed interdisciplinary training will result in a cohort of Earth Scientists with the cross-disciplinary expertise enabling them to tackle the problems posed in understanding the complex earth processes that moderate our surface environment.
iTECC's objectives are:
• Training of scientists with the ability to contribute to multi-disciplinary research ranging from solid Earth processes to climate, and apply their skills in academia and industry.
• Integration of research on present-day deformation with information from the geological record to understand how the lithosphere deforms.
• Significant improvement in the recovery and exploitation of tectonic, erosive, weathering and climatic records from sedimentary sequences.
• Evaluation of the impact of elevation and exhumation of the Himalaya on climate.
• Evaluation of the impact of climate, through erosion, on the tectonic evolution of the Himalayan orogen.
• Validation of climate models, using them to verify the interconnections between tectonics and climate.

The four science work-packages were designed to address each component of this integrated approach:
In WP1, testable models from the study of modern processes of tectonics and climate were developed, using the information from the sedimentary records to verify these models. Three iTECC fellows are working on lithosphere modeling (ER1, Cambridge University), surface-process modeling (ESR1, UGA Grenoble), and atmospheric circulation modeling (ESR2, CEA LSCE, Paris), respectively. ER1 performed analysis of surface displacements in the Ghorka earthquake that allowed a high precision geometry of the Himalayan megathrust to be determined. This formed the key data for assessing the relationship between earthquake cycles and the timing and mechanism of growth of the mountain range. The second appointment on the ER1 position worked on a valuable catalogue of well-located earthquakes for the Jammu and Kashmir Himalaya. The focus of ESR1 has been the relationship between climate (precipitation) variability and erosion in the context of landscape evolution modeling. Results of ESR2 show a significant influence of paleogeography on the Asian climate. The surface elevation of the Himalaya and Tibetan Plateau were shown to directly impact local temperatures and atmosphere circulation, resulting in increased precipitation rates over the southern Tibet and aridity over northern Tibet and in central Asia.

WP2 aimed at quantifying the controls on chemical weathering and physical erosion in the Himalaya by understanding the feedback loops with global atmospheric CO2 levels and hence climate. ESR3, based in Nancy, undertook the first extensive investigation of 40K-40Ca systematics in the Himalayan erosional system. The major discovery was that during Himalayan metamorphism, 40Ca, unlike 87Sr, remains remarkably resistant to metamorphism, allowing the distinction of carbonate and silicate sources in the dissolved load of the major Himalayan rivers. ESR 4, based in Potsdam, worked on stable-isotope analysis of biomarkers obtained from modern and recent sediments, whereas ESR5, based in Grenoble and seconded to Gand (Ghent), Belgium, worked on lake archives, focussing initially on the record of climatic changes during the Quaternary but turning more and more toward the paleo-seismological signal these archives bear.

WP3 used sedimentary records to infer the evolution of tectonics, weathering, erosion and climate through time. Two ERs and two ESRs have been working on sedimentary records. ER2 was based in an industry environment in India and has worked on sedimentary basin modelling, using public and industry seismic data to clarify the timing and origin of compressional structures providing evidence of inversion within the Barmer Basin and elucidate their relationship with the India-Asia collision. ER3 and ESR6, based at Lancaster University, have worked on detrital records using multiple isotopic techniques (U-Pb, Nd, and Hf isotopes for provenance analysis; 40Ar/39Ar and fission-track dating for paleo-exhumation rates) in Pakistan (ER3), and the eastern syntaxis and the Shillong plateau (ESR6), respectively. ESR 7 has focused on analysing two sections in the east and in the west of the Himalayan mountain chain to elucidate spatial and temporal variations in weathering intensity, using major and trace-elements, mineralogy, and Li isotopes.

WP4 involved development and refinement of analytical techniques needed to better interpret the past and present-day records of exhumation, erosion and climate processes. In WP4, 3 ESR’s and one industry-based ER have been working on instrumental innovation. ESR11, based at Cambridge University, has worked on purification techniques for obtaining pure Li and Mg salts that can be analysed using multi-collector inductively coupled mass spectrometry by column chromatography. ESR’s 9 and 10, based at the University of Bremen, have focused on setting up and testing new protocols for (U-Th)/He dating of apatite and zircon crystals, applying these techniques to newly collected samples from Nepal and India. ER4 and ESR8, based at industry partner ThermoFisher and the VUA, Vrije University Amsterdam respectively, focus on perfecting modern multi-collector noble-gas mass spectrometric techniques. The ER has set up a second identical noble-gas mass spectrometer in Bremen, whereas ESR8 focused on analysing downstream modifications of the detrital 40Ar/39Ar signal of source-exhumation rates, using the Brahmaputra River as a case study.
In each of the Work packages, significant progress has been made towards a better understanding of the studied processes as mentioned in the WP objectives in the DoW. This is underlined by the number of papers co-authored by multiple partners of iTECC.
In the period 36 – 54 months of the project contract, the ESRs have mostly focussed on concluding laboratory work and finalizing their PhD dissertations. During this period and following on into the post-contract period, the ESRs and their supervisors are preparing the results in the form of scientific publications.

In addition to the four Science work-packages, iTECC had 3 work-packages related to the functioning of the network activities:
WP5 – training under the Deputy Training, dr. Y. Najman of partner 2; Most of the training activities were scheduled in the first 24 months of the contract, whereas in the second part meetings were scheduled to encourage fast-track data exchange in research in progress (RiP-)meetings.
WP6 – Network management is run by the network Coordinator, professor dr. J.R. Wijbrans of partner 1 assisted by the iTECC Office at Stichting VU;
WP7 – Outreach and dissemination under the Deputy Outreach, professor dr. P. van der Beek at partner 5.
The highlight of this reporting period was the organization of the Himalaya-Karakorum-Tibet-Conference by iTECC fellows in the CNRS Conference Centre in Aussois, France (http://hkt2016.fr). The HKT conference series has been running for 2 decades and is focussed on bringing together scientists working on the geology of Tibet, the Himalaya and the Karakorum mountains. The meeting was attended by a wide mixture of US and EU based scientists with a substantial attendance of Indian, Chinese and Nepali scientists. iTECC contributed to the travel fund for young Asian scientists to encourage them to participate in the conference, as an outreach activity towards the local Himalayan science communities.
The iTECC website can be found at: http://www.itecc-eu.eu/