The Green Icebergs of the Ronne Ice Shelf
The Ronne Ice Shelf has been identified as a location that has produced "Green Icebergs". The current opinion is that circulatory actions under the shelf move minerals up into the lower layer of tech shelf. When the 'bergs" drift out to sea and deteriorate to the point of flipping upside down, the green lower layer is exposed. See the explanation at AWI's webpage.
Our research has shown that the Ronne Ice-shelf was impacted in a Perigee: Zero Terminal event. Our Proof Set for the Ronne Series covers the development of that solution set, which includes three earlier grazing and trenching events.
The event caused major disruption to the entire basin under the Ronne Ice-shelf, and left a clearly discernible signature of a PZ Terminal structure, as highlighted in this Google Earth composite.
Ronne Terminal Event
We interpret the findings of Green Icebergs as a manifestation of the extreme environmental conditions that existed at and shortly after the impact. The tumultuous excavation of the crater provided a ready source of minerals and isotopes to intact with the surviving ice in the vicinity.
The reader is referred to the page discussing the divot and cometary ejecta from this PZ crater event.
Significant marine-ice accumulation in the ablation zone beneath an Antarctic ice shelf, Authors: Khazendar, A.; Tison, J.L.; Stenni, B.; Dini, M.; Bondesan, A. Source: Journal of Glaciology, Volume 47, Number 158, June 2001, pp. 359-368(10), Publisher:International Glaciological SocietyAbstract: High-resolution crystallographic, salinity and isotopic analyses of a 45m ice core reveal the presence of a thick layer of marine ice near the grounding line of the Nansen Ice Shelf, Antarctica. The anomalous formation of marine ice in a zone assumed to be the site of active basal melting leads us to propose the hypothesis of large basal crevasses as a favorable environment for important marine-ice accretion. This hitherto unexplored possibility is supported by the overall field configuration and by the discrepancy in some ice properties between this core and the marine-ice sections of previous drilling projects. These findings could have important implications for the general stability of ice shelves and their disintegration processes. The specific properties of this core reveal that marine ice is post-genetically deformed.
These ice shelves have the peculiar characteristic to show marine ice outcrops at the glacier surface close to the ice shelf front, because of the very strong katabatic winds regime which is also partly responsible of the existence of the Terra Nova Bay polynya.
Ice Shelf Marine Ice (ISMIce, 1992- ongoing)