Horn Head greenschist with blastomylonitic texture and chlorite porphyroblasts.
This greenschist-facies metabasite sample was collected from a narrow, attenuated layer of dark green rock within psammites on the cliff-top near Horn Head. The rocks here are intensely sheared and associated with a major low-angle fault known as the Horn Head Slide. The attenuated band of metabasite can be traced laterally into a much thicker basic intrusion in less-deformed psammites. This intrusion is presumed to belong to the suite of dolerite and gabbro intrusions in the Dalradian Supergroup that were emplaced about 600 million years ago. In this rock chlorite porphyroblasts are fairly random in their orientation and overgrow a fine-scale compositional banding produced by intense shearing on the Horn Head Slide.
Neoproterozoic, Dalradian Supergroup 600 million years ago.
Rotation 1 - Straight extinction in biotite and chlorite
A group of iCRAG members (UCC, TCD, NUIG and UCD) in partnership with The Open University have created a new collection of Irish rocks and associated learning materials for the Virtual Microscope of Earth Sciences.
The project which is entitled 'The Geoscience e-Laboratory (GeoLab): Developing Digital Teaching and Learning Resources for the Virtual Microscope' seeks to develop open access teaching resources in the form of interactive exercises and assessment rubrics for the Virtual Microscope. Find out more about the project at the GeoLab website.
The Collection was created using funding from the Faculty of Engineering, Mathematics and Science at Trinity College, Dublin, and the National Forum Teaching and Learning Enhancement Fund. One sample (Merensky Reef) showcasing x-ray element maps in addition to the usual PPL/XPL/REF images was funded by Prof. Balz Kamber's MetalIntelligence EU training network grant.