Lectures

Lectures are open to all and there is no charge for admission. However regular in person attendees are expected to be members of the society.

Time:
7:45pm for 8:00pm

Venue:
In Person: Sorby Room, Wager Building, (formerly Geoscience),
The University of Reading, Whiteknights, Reading.
Use Car Park 8.
Via Zoom: Members are sent the joining link by email.
Non-members wishing to join a zoom lecture can request this using the registration link when shown. Requests should always be made at least 24hrs before the start time.
This lecture will be both in the Sorby room and via Zoom.


2022-06

Monday 6 June 2022

The evolution of the nitrogen cycle during the Proterozoic:

constraints from the study of Indian carbonatites.
Dr. Sudeshna Basu, Department of Earth Sciences, UCL
Non Members Registration

Nitrogen in the mantle can exist as different species (e.g. molecular N2, ammonium (NH4+), ammonia (NH3)) that affects its degassing, with implications towards the overall nitrogen budget of Earth. The 40Ar/36Ar ratios are distinct for different mantle reservoirs and the atmosphere. The δ15N signatures not only can differentiate between mantle and atmospheric components, but also is distinctive for any nitrogen that might have been subducted.

The Indian carbonatites from Khambamettu, Hogenakal, Newania, and Sevattur encompass a wide range in ages from 2500 to 770 Myrs, and entrain components from different mantle reservoirs. Although dominated by the subcontinental lithospheric mantle (SCLM), a deeper mantle component with contribution from a plume source cannot be ruled out. Nitrogen and argon from these carbonatites were extracted from mineral separates (carbonates and apatites) and analysed for their isotopic ratios (δ15N, 40Ar/36Ar) and elemental signatures (N2/36Ar, N2/40Ar). In this talk, based on the findings, I will focus on the different mantle components identifiable and, any change in the speciation of subducted nitrogen and its storage in the mantle over time. This will be related to the nitrogen budget for Earth and geological processes that may have simultaneously affected the carbon cycle.




Programme 2022

The programme for 2022 as currently proposed is also available as a pdf document.

Other programmes

Previous years programmes and other programme information can be found on the About us page.