TY - JOUR N2 - Charnockites – i.e., orthopyroxene-bearing felsic rocks – were formed in a deep-seated dry environment, either under plutonic or high-grade metamorphic conditions. Most charnockites known from the crystalline basement of Poland appear to be of Mesoproterozoic age (1.50–1.54 Ga), cogenetic with the Suwałki Anorthosite Massif, and associated with mangerite and granite members forming the AMCG suite of the Mazury Complex. Genetically distinct rocks, characterised by the presence of anhydrous minerals, e.g., orthopyroxene and garnet, were also recognised along 592 m of the Łanowicze PIG-1 borehole section, within the AMCG suite. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date the complexly zoned zircons. The ages of crystallisation of the charnockite protoliths from various depths at 1837±7, 1850±9, 1842±6, and 1881±16 Ma makes these rocks the oldest dated crust within this part of the Polish basement. The Łanowicze PIG-1 borehole section bears components from neighbouring tectonic domains known from Lithuania: the West and Middle Lithuanian (WL/MLD) domains considered as a continental margin at 1.84–1.86 Ga and the fragmented Latvia-East Lithuania (LEL) domain, where the oldest continental crust was generated at c. 1.89– 1.87 Ga. The metamorphic zircon overgrowths document a high-grade event at 1.79 Ga and then constrained at 1.5 Ga. Dating of pre-Mesoproterozoic crust cryptic within the AMCG Mazury Complex provides valuable information on the nature of the pre-existing blocks formed during the long lasting Svecofennian orogeny. L1 - http://czasopisma.pan.pl/Content/110347/PDF/1_Krzeminska.pdf L2 - http://czasopisma.pan.pl/Content/110347 PY - 2019 IS - No 4 EP - 511 DO - 10.24425/agp.2019.126445 KW - Magmatic protolith KW - SHRIMP dating KW - Dry metamorphism KW - Svecofennian orogeny KW - Active continental margin A1 - Krzemińska, Ewa A1 - Łukawska, Aleksandra A1 - Bagiński, Bogusław PB - Komitet Nauk Geologicznych PAN PB - Wydział Geologii UW VL - vol. 69 DA - 2019.12.07 T1 - U-Pb zircon geochronology of high-grade charnockites– exploration of pre-Mesoproterozoic crustin the Mazury Complex area SP - 489 UR - http://czasopisma.pan.pl/dlibra/publication/edition/110347 T2 - Acta Geologica Polonica ER -