Geo chem is try and geo chron ol ogy of the Jawornik granitoids, Orlica-Œnie¿nik Dome, Sudetes, Po land
Dawid BIA£EK1, *
1 Uni ver sity of Wroc³aw, In sti tute of Geo log i cal Sci ences, pl. M. Borna 9, 50-204 Wroc³aw, Po land
Bia³ek, D., 2020. Geo chem is try and geo chron ol ogy of the Jawornik granitoids, Orlica-Œnie¿nik Dome, Sudetes, Po land.
Geo log i cal Quar terly, 64 (4): 000–000, doi: 10.7306/gq.1567 As so ci ate Ed i tor: Leszek Krzemiñski
The Jawornik granitoids in trude, in vein-like form, a se quence of a polymetamorphic meta vol can ic and metapelitic rocks of the Orlica-Œnie¿nik Dome, Sudetes, Po land. This pa per pro vides whole-rock geo chem i cal data, sen si tive high-res o lu tion ion microprobe (SHRIMP) U-Pb zir con geo chron ol ogi cal data as well as 40Ar-39Ar age de ter mi na tions to con strain the ge netic and tem po ral re la tion ships of the dif fer ent rock types form ing these veins. Based on mac ro scop i cally vis i ble fea tures of the granitoids and their re la tion ship with tec tonic struc tures vis i ble in the coun try rocks, four va ri et ies of the Jawornik granitoids have been dis tin guished: am phi bole- and bi o tite-bear ing gran ites (HBG), bi o tite-bear ing gran ites (BG), bi o tite- and mus co - vite-bear ing gran ites (BMG) and mus co vite-bear ing gran ites (MG). The Jawornik granitoids as a whole show a lim ited but sig nif i cant vari a tion in ma jor el e ment chem i cal com po si tion, with SiO2 rang ing from 65 to 76 wt.% (av er age 69.16 wt.%, n = 24). They are subalkalic, peraluminous and calc-al ka line [av er age A/CNK = 1.07, av er age (Na2O + K2O) = 7.75, av er age (Fe2O3t
/(Fe2O3t
+ MgO) = 0.59]. Close in spec tion of their geo chem i cal pa ram e ters showed that the sam ples in ves ti gated can be sub di vided into two groups. The first group, the HBG, BG, and BMG va ri et ies, com pris ing most of the granitoids in the Z³oty Stok-Skrzynka Tec tonic Zone, were formed by melt ing of greywackes or/and am phi bo lites. The MG, be long ing to the sec ond group, were formed by par tial melt ing of a more fel sic source. The HBG yielded a zir con U-Pb age of 351 ±1.3 Ma and well-de fined 40Ar-39Ar pla teau ages for hornblende (351.1 ±3.9 Ma) and co ex ist ing bi o tite (349.6 ±3.8 Ma), in di cat ing prob a - bly the old est mag matic event in this re gion. Zir cons from the MG, the youn gest rock va ri ety on the ba sis of their re la tion ship with the tec tonic struc tures in the host rocks, yielded a U-Pb age of 336.3 ±2.4 Ma, though based on three points only. The biotites and mus co vites from the BMG have 40Ar-39Ar pla teau ages of 344.1 ±4.7 Ma and 344.6 ±3.8 Ma, re spec tively. These data, in com bi na tion with al ready pub lished iso to pic ages, sug gest that the Jawornik granitoids in truded host rocks of the Orlica-Œnie¿nik Dome in three stages, at ~350, ~344 and ~335 Ma.
Key words: Jawornik granitoids, geo chem is try, geo chron ol ogy, Sudetes, Variscan granitoids.
INTRODUCTION
The Sudetes, lo cated in south west ern Po land, north east ern Bo he mia and north ern Moravia, rep re sent a small por tion of the Variscan Orogenic Belt in Eu rope and form the NE part of the Bo he mian Mas sif (Fig. 1). Geo log i cal units, be long ing to all four ma jor lithotectonic do mains of the Bo he mian Mas sif (i.e.
Saxothuringian, Teplá-Barrandian, Moldanubian and Bruno - vistulian do mains), make up the com plex struc tural mo saic of the Sudetes (Matte et al., 1990; Cymerman et al., 1997;
Franke, 2000; Franke and ¯elaŸniewicz, 2002; Mazur et al., 2006, 2015; Schulmann et al., 2014). The as sem bly of these units oc curred dur ing Late De vo nian to Early Car bon if er ous terrane col li sions (e.g., Matte et al., 1990; Cymerman et al.,
1997; Aleksandrowski and Mazur, 2002); the Variscan granitoids form a por tion of the rock in ven tory in all of them.
They dif fer in age, com po si tion and their tec tonic con text. The Bo he mian Mas sif is an ex am ple of a hot orogen with nu mer ous compositionally di ver si fied granitoid plutons. The plutonism was ac tive for nearly 80 My, and on the ba sis of their tec tonic set - tings, age and petro gen esis, four groups of plutons have been dis tin guished (Žák et al., 2014). The old est (~375 Ma), vol u met - ri cally small, granitoid bod ies, are subduction-re lated, con - nected with early stages of plate col li sion. Plutons be long ing to the next two groups (354–346 Ma and 340–335 Ma) were emplaced dur ing con sec u tive phases of orogenic de for ma tion.
In the fourth group there are plutons emplaced dur ing fi nal stages of the Variscan orog eny (330–320 Ma) and post- orogenically (~300 Ma). The larg est Sudetic plutons – the Karkonosze Pluton, Strzegom-Sobótka Mas sif, Žulowá Pluton, and small in tru sions that crop out in the Strzelin Mas sif, emplaced on the pe riph ery of the Variscan orogen, can be clas - si fied as late- to post-tec tonic (Oberc-Dziedzic and Kryza, 2012;
Kryza et al., 2014; Laurent et al., 2014; Turniak et al., 2014).
Older and smaller granitoids of the cen tral Sudetes are spa tially
* E-mail: dawid.bialek@uwr.edu.pl
Received: March 6, 2020; accepted: July 30, 2020; first published online: October 30, 2020
and tem po rally re lated to shear- or fault-zones (Parry et al., 1997; Pietranik et al., 2013; Oberc-Dziedzic et al., 2015;
Jastrzêbski et al., 2018; Jokubauskas et al., 2018). These de - for ma tion zones – like the Niemcza Shear Zone or the Staré Mìsto Belt – are the re sults of oblique col li sion of Teplá- Barrandian, Moldanubicum and Brunovistulicum dur ing the Early to Late Car bon if er ous (Matte et al., 1990; Schulmann and Gayer, 2000). Ac cord ing to Jastrzêbski et al. (2013) struc tural de vel op ment of the Staré Mìsto Belt may have hap pened even ear lier, in the Famennian. One of such de for ma tion zone is the Z³oty Stok-Skrzynka Tec tonic Zone (ZS-STZ), which was in - truded by the Jawornik granitoids. Knowl edge of petro gen esis and geo chron ol ogy of the Jawornik granitoids can be used to re trace the tem po ral and dy namic evo lu tion of the Orlica - -Œnie¿nik Dome. This study aims to es tab lish the age, and con - strain the in tru sion se quence and source char ac ter is tics, of these granitoids.
REGIONAL SETTING
LITHOSTRATIGRAPHY OF THE ORLICA-ŒNI¯ENIK DOME
The Orlica-Œnie¿nik Dome (OSD) be longs to the cen tral Sudetes, and is ex posed in the east ern part of the Bo he mian Mas sif. The core of the dome is com posed of am phi bo lite fa cies grade orthogneiss bod ies, lo cally con tain ing lenses of (ul tra) high pres sure rocks (eclogite and granulite), al ter nat ing with synforms of pri mary vol cano-sed i men tary rocks (Don et al., 1990). The lat ter were orig i nally di vided into two dis tinct units – the M³ynowiec and Stronie for ma tions (Fischer, 1936; Don et al., 2003). The M³ynowiec For ma tion, ~2000 m thick, is com - posed of a mo not o nous suc ces sion of paragneisses with in ter - ca la tions of mica schist and am phi bo lite. The more het er o ge - Fig. 1. Geo log i cal sketch map of the Sudetes (af ter Aleksandrowski and Mazur, 2002)
with re spect to the Cen tral Eu ro pean Variscides (in set map)
The Z³oty Stok-Skrzynka tec tonic zone is marked with a bold rect an gle; EFZ – Elbe Fault Zone, ISF – Intra-Sudetic Fault, MGH – Mid-Ger man Crys tal line High, MO – Moldanubian Zone, MS – Moravo-Silesian Zone, NP – North ern Phyllite Zone, RH – Rhenohercynian Zone, OFZ – Odra Fault Zone, SX – Saxothuringian Zone, OSD – Orlica-Œnie¿nik Dome, RT – Ramzová Thrust
neous Stronie For ma tion, ~4000 m thick, is a suc ces sion of mainly mica schists, ac com pa nied by acid and ba sic meta - volcanogenic rocks, quartzites, mar bles and paragneisses, wide spread through out the en tire OSD (Don et al., 1990; Don et al., 2003). The fel sic orthogneisses, form ing the core of the dome, are tra di tion ally sub di vided into two main types: coarse- grained, augen, banded Œnie¿nik gneiss es and fine-grained, lo - cally migmatitic Giera³tów gneiss es (Fischer, 1936; Don et al., 1990). A protolith age of ~520–490 Ma is ac cepted for both orthogneiss va ri et ies (Bröcker et al., 2009 and ref er ences therein), and they are thought to have been de rived by anatexis of pre-ex ist ing con ti nen tal crust (Lange et al., 2005). Sev eral au thors have pro posed that both orthogneiss types re sult from meta mor phism and dif fer en tial de for ma tion of the same gran ite (Turniak et al., 2000; Lange et al., 2005; Cho pin et al., 2012b), though this opin ion has been ques tioned by ¯elaŸniewicz et al.
(2006).
Gen er ally, ages of de tri tal zir con grains from rocks of the vol cano-sed i men tary suc ces sion im ply a Neoproterozoic to Early Or do vi cian max i mum age of de po si tion (Jastrzêbski et al., 2010; Mazur et al., 2012). These metasedimentary rocks un der went, dur ing the Variscan orog eny, prograde meta mor - phic evo lu tion from ~3.4–4.5 kbar, with a peak P-T con di tions of 5-9 bar and 460–650°C fol lowed by de com pres sion to 2–3.5 kbar at 530–600°C (Murtezi, 2006; Jastrzêbski, 2009;
Skrzypek et al., 2011a, b; Štípská et al., 2012).
TECTONIC DEVELOPMENT
OF THE Z£OTY STOK-SKRZYNKA TECTONIC ZONE
In the NE part of the OSD in the area be tween Z³oty Stok and Skrzynka, rocks of the Stronie For ma tion were in truded by sheets of the Jawornik granitoids (Fig. 2). This por tion of the OSD is re ferred to in the lit er a ture as the Z³oty Stok-Skrzynka Tec tonic Zone (Finckh, et al., 1942; Don, 1964; Koz³owska - -Koch, 1973; Cwojdziñski, 1977) or Z³oty Stok-Skrzynka shear zone (Cymerman, 1996). The polymetamorphic rocks of the ZS-STZ have at tracted much at ten tion be cause they may pos - si bly pro vide im por tant clues to un der stand ing the char ac ter of the bound ary be tween the East and West Sudetes. The or i gin of this zone has been as so ci ated by Bederke (1929) with de vel - op ment of the Ramzová overthrust. On the other hand, Cloos (1922) con sid ered that this zone was linked with the Niemcza Shear Zone, lo cated ~20 km far ther to the north.
Gen er ally, mica schists of the ZS-STZ ex pe ri enced am phi - bo lite fa cies meta mor phism (Burchart, 1958; Murtezi, 2006;
Skrzypek et al., 2014). Min eral equi lib ria mod el ling in the KFMASH sys tem used by Murtezi (2006) and in the MnNCKFMASHTO sys tem used by Skrzypek et al. (2014) in di - cate prograde evo lu tion of up to 625–640°C and 6–8.5 kbars, fol lowed by P-T de crease at 2–2.5 kbar and 500°C (Skrzypek et al., 2014). Most re search ers work ing in this area in re cent years agree that at least three deformational events are re cog nis able (Don et al., 1990; Štípská et al., 2004; Cho pin et al., 2012a;
Skrzypek et al., 2014; Závada et al., 2017; for an al ter na tive view see Cwojdziñski, 1977; Dumicz, 1988; Cymerman, 1996;
Murtezi, 2006). The ear li est subhorizontal fo li a tion S1, be ing the re sult of crustal thick en ing (Štípská et al., 2004), is pre - served only lo cally, mostly in quartz-rich lithologies. Crustal - -scale fold ing (D2 de for ma tion) led to S1 be com ing ver ti cal and the de vel op ment of a steep S2 fab ric. Both S1 and S2 foliations were in turn lo cally re worked by metre-scale or smaller open re -
cum bent folds with de vel op ment of an S3 ax ial plane cleav age gently dip ping to the NW. The dom i nant meta mor phic fo li a tion S2 strikes NE–SW and dips steeply (al most ver ti cally lo cally) to the WNW or SE (Don et al., 1990; Štípská et al., 2004).
PREVIOUS STUDIES ON THE JAWORNIK GRANITOIDS
The main Jawornik granitoids vein form a lin ear in tru sion 11 km in length and 1.2 km at its wid est point, nar row ing to the SW (Fig. 2). Thick nesses of sat el lite sills, ex ten sively de vel - oped in the SW part of the ZS-STZ, range from <5 cm to >20 m, but are com monly <2 m. Some of these veins, marked on maps as ho mog e nous, are in fact a se ries of schist-granitoid veinlets.
At a map scale those sills are aligned SW–NE, par al lel to the gen eral trend of the tec tonic zone (Cwojdziñski, 1979). The ori - en ta tion of the mag matic and sub-mag matic struc tures in the larg est veins are sim i lar to the ori en ta tion of the dom i nant meta - mor phic fo li a tion in the coun try rocks. How ever, at the meso - scale, small veins lo cally are par al lel to the older, subhorizontal fo li a tion. In a few places granitoid dykes cross-cut, at high an - gle, the main fo li a tion in the host rocks (Cwojdziñski, 1977;
Bia³ek and Werner, 2002; Skrzypek et al., 2014).
In the field, va ri et ies of the Jawornik granitoids are mac ro - scop i cally poorly dis tin guish able and het er o ge neously dis trib - uted. Based on min eral com po si tion and chem i cal anal y sis, three types of granitoid can be iden ti fied: granodiorites, monzo - nitic gran ites and tonalites (Nìmec, 1951; Burchart, 1958;
Bia³ek, 2003). All these va ri et ies have been vari ably de formed and meta mor phosed. In places, ig ne ous tex tures are well-pre - served but else where gran ites have been trans formed into augen gneiss es and mylonites. Bi o tite and hornblende crys tals, ac com pa nied by feld spar ag gre gates and quartz rib bons, usu - ally form a weak fo li a tion plane in the rocks. Only in few sam ples is a strong bi o tite fo li a tion de vel oped. Micro struc tures in the Jawornik granitoids point to a mag matic and partly sub mag - matic de vel op ment of the fab ric with mi nor solid-state over print (Burchart, 1958; Bia³ek, 2003).
Pre vi ously pub lished geo chron ol ogi cal data al low dis tinc - tion of three groups of Pb/Pb and U/Pb zir con ages for the Jawornik granitoids: ~351 ±3 – 351 ±1 Ma for am phi bole- and bi o tite-bear ing granodiorites (HBG) (Bia³ek, 2014; Skrzypek et al., 2014), 342 ±4 Ma for bi o tite- and mus co vite-bear ing grano - diorites (BMG) (Bia³ek, 2014) and 333 ±4 Ma for gran ite and granodiorite (Závada et al., 2017; Jastrzêbski et al., 2018).
Monazite in the bi o tite-bear ing granodiorite (BG) pro vided a Th-U-to tal Pb age of 343 ±4 Ma (Budzyñ and Jastrzêbski, 2016). This age is con sis tent with a bi o tite pla teau cool ing age of 343 ±4 and a mus co vite pla teau age of 344 ±4 Ma (Bia³ek and Werner, 2004). 40Ar-39Ar spec tra of hornblende and bi o tite from a HBG granodiorite sam ple gave pla teau ages of 351 ±4 and 350 ±4 Ma, re spec tively (Bia³ek and Werner, 2004).
ANALYTICAL METHODS
ZIRCON U-Pb DATING
The rock sam ples were crushed and milled in the min eral sep a ra tion lab o ra tory of the In sti tute of Geo log i cal Sci ences, Uni ver sity of Wroc³aw, Po land. Light and heavy min er als were
sep a rated us ing stan dard tech niques, i.e., mag netic and elec - tro mag netic sep a ra tors and heavy liq uids. From the den sity frac tion d >3.0 g/cm3, sep a rated in so dium polytungstate aque - ous so lu tion, zir cons were hand-picked and then washed sev - eral times in dou bly dis tilled wa ter. The zir con pop u la tion were mounted at the John de Laeter Cen tre for Iso tope Re search at Cur tin Uni ver sity, West ern Aus tra lia. Ap prox i mately 100 grains
from each pop u la tion along with ap pro pri ate stan dards (zir cons BR266, Temora 2 and NBS 610 glass) were mounted in two 24 mm di am e ter ep oxy discs, pol ished to a 1 µm fin ish and gold coated. The mounted zir cons were pho to graphed in trans mit ted light and ex am ined by cathodoluminescence (CL) im ag ing on a Philips XL-30 SEM. The U-Pb iso to pic anal y ses were made on a SHRIMP II in stru ment at the John de Laeter Cen tre for Iso - Fig. 2. De tailed geo log i cal map of the Z³oty Stok–Skrzynka tec tonic zone (af ter Cwojdziñski, 1977)
with lo ca tions of the sam ples that were ana lysed for this study The sam ples that were dated are in di cated in bold
tope Re search. The an a lyt i cal pro ce dures for the Cur tin con - sor tium SHRIMP II have been de scribed by Ken nedy and de Laeter (1994) and are sim i lar to those de scribed by Compston et al. (1984) and Wil liams (1998). Typ i cally, a 25–30 mm di am e - ter spot was used, with a mass-fil tered 02-pri mary beam of 2–3 nA. Data for each spot is col lected in sets of 6 scans through the mass range of 196Zr2O+, 204Pb+, Back ground, 206Pb+, 207Pb+,
208Pb+, 238U+, 248ThO+, 254UO+. The pro grams SQUID II and Isoplot (Lud wig, 2003, 2009) were used for data pro cess ing. Er - rors cited for in di vid ual anal y sis in clude er rors from count ing sta tis tics, the com mon-Pb cor rec tion, and the U-Pb cal i bra tion er ror based on reproducibility of U-Pb mea sure ments of the stan dard, and are at the 1s level.
40Ar-39Ar DATING
Bi o tite, hornblende and mus co vite were sep a rated at the In - sti tute of Geo log i cal Sci ences, Uni ver sity of Wroc³aw, Po land, us ing stan dard min eral sep a ra tion tech niques. Min eral con cen - trates were sent to Ac ti va tion Lab o ra to ries Ltd., in Can ada. The sam ples wrapped in Al foil were loaded in evac u ated and sealed quartz vi als with K and Ca salts and pack ets of LP-6 bi o - tite in ter spersed with the sam ples to be used as a flux mon i tor.
The sam ples were ir ra di ated in the nu clear re ac tor for 48 hours (J = ~0.0045). The flux mon i tors were placed be tween each two sam ples, thereby al low ing pre cise de ter mi na tion of the flux gra - di ents within the tube. Af ter the flux mon i tors were run, J val ues were then cal cu lated for each sam ple, us ing the mea sured flux gra di ent. LP-6 bi o tite has an as sumed age of 128.1 Ma. The neu tron gra di ent did not ex ceed 0.5% on sam ple size. 40Ar-39Ar step-heat ing ex per i ments were ac com plished in a quartz re ac - tor heated by ex ter nal fur nace. For tem per a ture mon i tor ing a ther mo cou ple was used. The Ar iso tope com po si tion was mea - sured us ing a Micromass 5400 static mass spec trom e ter. The 1200°C blank of 40Ar did not ex ceed n × 10–10 STP. The er rors for all ana lysed min er als 40Ar-39Ar ages are quoted at 1 s level.
More in for ma tion on the pro ce dure, pre ci sion and ac cu racy of ACTLABS Ar-Ar anal y ses can be found at www.actlabs.com.
WHOLE-ROCK MAJOR AND TRACE ELEMENTS
Rock sam ples were ex am ined by op ti cal mi cros copy and 24 un al tered or least al tered sam ples were cho sen for geo chem i - cal anal y sis. The rocks were crushed by a jaw crusher and then pul ver ized in an ag ate mill. Anal y ses were per formed at the Ac - ti va tion Lab o ra to ries Ltd., On tario, Can ada (Actlabs). The re - sults were ob tained us ing neu tron ac ti va tion anal y sis (INAA) for Au, As, Br, Co, Cr, Cs, Hf, Hg, Rb, Sb, Sc, Ta, Th, U, W, La, Ce, Nd, Sm, Eu, Tb, Yb and Lu and in duc tively-cou pled plasma – atomic emis sion spec trom e try (ICP-AES) for SiO2, TiO2, Al2O3, Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5, Ba, Sr, Zr, Y, Sc, Be and V. Ad di tion ally Nb, Rb, Pb and Ga have been ana lysed by X-ray flu o res cence (XRF). The an a lyt i cal pro ce dures, ap - plied stan dards and ac cu racy for the 4Litho pack age used are avail able at the ACTLABS website (www.actlabs.com). Chem i - cal di a grams were mostly gen er ated us ing GCDKit soft ware (Janoušek et al., 2006).
Microprobe anal y ses were per formed by means of a Cameca SX-100 (at the Inter-In sti tute Microanalytical Com plex
for Min er als and Syn thetic Sub stances, Fac ulty of Ge ol ogy, Uni ver sity of War saw) with wave length-dispersive spec trom e - ters (WDS) un der the fol low ing con di tions:
–4 s count ing time (peak), –4 s count ing time (back ground), –6–8 mm beam di am e ter, –15 kV ex ci ta tion volt age, –15 nA spec i men cur rent.
RESULTS
Based on field char ac ter is tics, tex tures and min er al ogy, four groups of the Jawornik granitoids were dis tin guished and cho - sen for fur ther ex am i na tion:
– type I (BG) – most typ i cal, me dium-grained rocks with por phy ritic tex tures and a fo li a tion de fined by aligned bi o tite and flat tened feld spar pheno crysts. Bi o tite (Bt) is the only mafic sil i - cate; Bt is rel a tively iron-rich with Fe/(Fe + Mg) rang ing from 0.40 to 0.43, and shows lit tle vari a tion in tet ra he dral alu mi num (from 2.26 to 2.72 apfu for O = 11); the compositional range of K-feld spar is Or87–95; plagioclase is pre dom i nantly rep re sented by oligoclase (An12–25), rarely al bite;
– type II (HBG) – me dium- to fine-grained (~2–6 mm), am - phi bole-bear ing rocks with a weak gneissosity de fined by the align ment of bi o tite grains. Bi o tite oc curs as a pri mary min eral phase and as a re ac tion prod uct as so ci ated with the mar gins of many am phi bole grains; am phi bole com po si tion ranges from tremolite to par ga site, and is rel a tively iron-rich, with Fe/(Fe + Mg) ra tios rang ing from 0.41 to 0.6, and Ti from 0.18 to 0.28 (for O = 22). Am phi bole com po si tions at the mar gin show higher Si, Ti, Mg, and AlTOT con tents, and the com po si tions are pro gres - sively en riched in Ca, Na, Fe and K to ward the cen tre; the compositional range of K-feld spar is Or83–94; plagioclase ranges from oligoclase to al bite (An2–26);
– type III (BMG) – me dium-grained rocks with pri mary mus - co vite. Fab ric is de fined by mica laminae, par al lel ar range ment of flat tened feld spars and elon gated quartz grains. The compositional range of K-feld spar is very nar row – Or96–99; plagioclase has up to 27% An in the in ter nal part and 1% An on the rim; Fe/(Fe + Mg) ra tio and Ti con tent of bi o tite are - 0.40–0.43 and 0.21–0.23, re spec tively; Na/(Na + K) ra tio in mus co vite var ies from 0.10 to 0.13, and Si from 7.18 to 7.39 (for O = 22);
– type IV (MG) – leucocratic, coarse-grained rocks (~5–15 mm), with tex ture vary ing from equigranular to por phy - ritic, with large euhedral feld spar pheno crysts. Fo li a tion is poorly de vel oped and de fined by mica flakes. K-feld spar con - tains Or93–96; plagioclase has 17% An in the cen tre and 3% An in the rim; Na/(Na + K) ra tio in mus co vite ranges from 0.08 to 0.10, and Si from 7.22 to 7.36 (for O = 22).
ZIRCON U-Pb GEOCHRONOLOGY
Two sam ples from type HBG (GJ117) and from type MG (GJ44) were se lected for zir con U-Pb dat ing, and all data are given in Ap pen dix 1*. They were cho sen due to their dif fer ent re la tion to de for ma tion struc tures in the coun try rocks. Sam ple GJ117 with clearly vis i ble fo li a tion was taken from a small vein par al lel to the subhorizontal S1 fo li a tion in the sur round ing
* Supplementary data associated with this article can be found, in the online version, at doi: 10.7306/gq.1567
metasedimentary rocks. Sam ple GJ44 co mes from an iso tro pic patch, which cross-cuts steeply dip ping S2 fo li a tion.
Most zir con grains from sam ple GJ117 show in CL two dis - tinct zones (Fig. 3). A bright CL core which is typ i cally euhedral to sub-rounded in shape, and a very dark rim, sug gest ing high ura nium con cen tra tion. The rim is euhedral and acicular and ex hib its os cil la tory zon ing, typ i cal of ig ne ous grains. Un zoned grains are en tirely com posed of high-ura nium, dark ma te rial.
Core com po nents are vari able in tex ture and CL re sponse, pos -
si bly sug gest ing more com plex or i gins. The ma jor ity of the rims are rel a tively ho mo ge neous, al though some grains show os cil - la tory zon ing. The data from sam ple GJ117 were col lected un - der sep a rate con di tions for the cores and rims. The cores were ana lysed with a stan dard 2 nA pri mary beam, then the rims were ana lysed with a pri mary beam re duced to 0.8 nA in or der to re duce the sig nal from the very high ura nium con cen tra tion.
This change had no ef fect on the data pro duced from the in stru - ment for the stan dard ref er ence ma te ri als.
Fig. 3. Cathodoluminescence (CL) im ages of zir cons from sam ple GJ117 – HBG va ri ety Scale bar 100 mm
The zir con cores ana lysed have vari able U (36–1321 ppm) and Th (5–377 ppm) con cen tra tions, and Th/U ra tios rang ing from 0.04 to 0.82 (mean = 0.34). The data from the cores of zir - con grains from sam ple GJ117 show a spread of ages from
~350 to ~650 Ma, with the ma jor ity of the data clus tered to - wards the youn ger ages. Within this range of ages there are two more sig nif i cant groups at ~350 and ~450 Ma. The con cordia plots for these ages are seen in Fig ure 5, and give ages of 351
±1.3 and 455 ±5.2 Ma re spec tively. Or do vi cian ages, ~460 Ma, were al ready re ported from mica schist of the Stronie For ma tion by Jastrzêbski et al. (2010) but the mean ing of this age is un - clear. It is pos si ble that these cores are xeno crysts which ex pe - ri enced some Pb-loss due to a Car bon if er ous ther mal ep i sode.
The ~350 Ma group rep re sent the youn gest anal y ses from the core group and form a dis tinctly sep a rate group. It is pos si ble that these ages rep re sent the time of recrystallisation of the core ma te rial, al though this is not sup ported by any dis tinct change in U con tent (<400 ppm) or Th/U ra tio. The rims from sam ple GJ117 are sig nif i cantly higher in ura nium con cen tra - tion, rang ing from 885 to nearly 4000 ppm, with a sim i lar Th range (13–398 ppm) and lower Th/U ra tios (0.01–0.23, mean = 0.12). The rims also show a range of ages from ~200 to
~380 Ma, with the ma jor ity of anal y ses at the older end of the spec trum. The old est ages over lap with the youn gest group from the cores. In most cases the rim anal y sis from any in di vid - ual zir con is sig nif i cantly youn ger than the core from the same grain. The 25 Myr. dif fer ence for the con cordia age of the zir con rims (see Fig. 5D, F) can be ex plained by the fact that the older age re flects in com plete ness of recrystallization of xeno crysts dur ing meta mor phism, whereas the youn ger age cor re sponds to newly formed zir con rims. The youn ger age groups, ~304 Ma and es pe cially ~336 Ma, are very sim i lar to the ages seen in sam ple GJ44 and re ported by Jokubauskas et al. (2018) from granitoids of the K³odzko-Z³oty Stok in tru sion and may re flect youn ger ther mal ep i sodes.
Grains from sam ple GJ44 show a va ri ety of morphologies and zon ing pat terns, from os cil la tory to sec tor zon ing (Fig. 4).
They are typ i cally euhedral to sub-rounded and >100 mm in di - am e ter; the ma jor ity of grains ap pear to be frag ments of larger
grains. Some grains show a dis tinct rim of high-CL re sponse, typ i cally sig ni fy ing low ura nium con tent (Fig. 4). The zir con grains from this sam ple are sig nif i cantly poorer in ura nium (10–128 ppm) while tho rium con tents (10–133 ppm) are in a sim i lar range as in the cores of GJ117 zir cons, so Th/U ra tios are nat u rally higher (0.08–1.71, mean = 0.73). The zir cons in sam ple GJ44 show a large spread of ages from ~250 Ma to 2.8 Ga. No ages pro duce a par tic u larly sig nif i cant clus ter, with only a small group of 3 zir con grains at ~340 Ma. The con cordia age for this group is 336.3 ±2.4 Ma, al though with only 3 points this is not a sta tis ti cally sig nif i cant value. Fig ure 5G and H shows two Wether ill con cordia di a grams for sam ple GJ44 show ing the en tire range of ages ob tained in clud ing a rel a tive den sity dis tri bu tion, and a “close up” of the ages <900 Ma. Ages youn ger than ~336 Ma could re flect Pb-loss dur ing a youn ger ther mal ep i sode, ~300 Ma, de scribed by Jokubauskas et al.
(2018) from the ad ja cent K³odzko-Z³oty Stok in tru sion.
40Ar-39Ar DATING
Sam ples of two va ri et ies of the Jawornik granitoids – HBG and BMG – were dated by the 40Ar-39Ar step-heat ing method.
Four min eral aliquots and as so ci ated flux mon i tors were ana - lysed and re sults are given in Ap pen dix 2 and Fig ure 6. All sam - ples show age spec tra with well-de fined pla teaus. Re sults of isochron re gres sion in all cases are con cor dant with pla teau age val ues.
Bi o tite from the HBG va ri ety (sam ple GJ25) yielded a spec - trum with a well-de fined pla teau for tem per a ture range 725–1050°C and age value of 349.6 ±3.8 Ma. Low and high tem per a ture steps are char ac ter ized by lower age val ues and by in creased Ca/K ra tios. Hornblende from the same sam ple dis plays flat age spec tra with a well-de fined pla teau for tem per - a ture range 950–1150°C and age value of 351.1 ±3.7 Ma. Pla - teau points are char ac ter ized by Ca/K ra tios ~7–12. An in verse isochron age of 355 ±7 Ma is con cor dant with the pla teau age.
The pla teau age can be ac cepted as a good es ti mate of the age of the clos ing K-Ar iso to pic sys tem in the hornblende.
Fig. 4. Cathodoluminescence (CL) im ages of zir cons from sam ple GJ44 – MG va ri ety
Fig. 5. SHRIMP zir con U-Pb con cordia di a grams for sam ples GJ117 and GJ44
Bi o tite from the BMG va ri ety (sam ple GJ78b) yielded a spec trum with a well-de fined pla teau af ter the first two steps (at 450 and 550°C) char ac ter ized by lower age val ues. Two low tem per a ture steps are dis tin guished also by higher Ca/K val - ues. This points to sig nif i cant con tri bu tion from a Ca-rich min - eral phase. Isochron anal y sis on the pla teau points re veals a lin ear re gres sion with an ini tial 40Ar-36Ar age of 274 ±18. This rules out any in flu ence of 40Ar ex cess. An in verse isochron age of 344.7 ±4.7 Ma is con cor dant with the pla teau age (343.1
±3.8 Ma) and with the to tal fu sion age (341.7 ±3.8 Ma). In that case the most pre cise weighted mean pla teau age can be ac - cepted as a good es ti mate of the age of K/Ar iso tope sys tem clo sure. The 40Ar/39Ar age spec tra of mus co vite from this sam - ple show mi nor in ter nal dis cor dance with a well-de fined pla teau for a tem per a ture range from 725 to 105°C and age value of 344.6 ±3.8 Ma. Low and high tem per a ture steps are char ac ter - ized by lower age val ues and by in creased Ca/K ra tios.
WHOLE-ROCK GEOCHEMISTRY
Twenty-four sam ples of the ear lier de scribed va ri et ies were se lected for anal y sis – eight from the HBG va ri ety, nine from BG, six from BMG and one from MG. Re sults are given in Ap - pen dix 3. The HBG sam ples show a rel a tively nar row range of SiO2 con tents of 66.56–68.53 wt.%, Na2O + K2O con tents of 7.55–8.09 wt.%, TiO2 con tents of 0.303–0.399 wt.% and Mg#
val ues of 80.5–89.5. They are char ac ter ized by mod er ately en - riched light REE, rel a tively flat heavy REE [(La/Yb)N = 6.36–21.53, with neg a tive Eu anom a lies (Eu/Eu* = 0.58–0.76)
(Fig. 7A)]. The sam ples are en riched in large-ion lithophile el e - ments (LILEs; eg., Cs, Rb, Th, U, Pb) and show pro nounced neg a tive Nb, P and Ti anom a lies on a prim i tive-man tle-nor mal - ized vari a tion di a gram (Fig. 7B).
The BG has a wide range of ma jor and trace el e ment con - tents. The BG sam ples range in SiO2 con tent from 65.26 to 71.55 wt.%, Na2O + K2O con tents range from 7.24 to 9.18 wt.%, TiO2 con tents from 0.201 to 0.452 wt.% and Mg# from 67.8 to 93.2. The chondrite-nor mal ized REE pat terns and prim i tive- man tle-nor mal ized di a grams of BG and HBG show sim i lar dis - tri bu tion pat terns (Fig. 7A, B).
The BMG sam ples con tain 68.47–71.13 wt.% SiO2, 6.84–8.22 wt.% Na2O + K2O, 0.22–0.33 wt.% TiO2 and Mg#
val ues of 74.5–85.4. They have higher Al2O3, Na2O and lower K2O, MgO, Fe O2 t3 and P2O5 while LREE are slightly more frac - tion ated than in the HBG and BG sam ples, with (La/Yb)N ra tios of 15.34–21.72, and (Eu/Eu*) ra tios of 0.68–1.27.
Only one sam ple of the MG has been as this va ri ety is ex - tremely rare in the area stud ied. With the ex cep tion of SiO2, the value of which is 75.81 wt.%, all other ma jor el e ments have con - cen tra tions lower than in the va ri et ies de scribed above: Na2O + K2O con tent of 5.75 wt.%, TiO2 con tent of 0.11 wt.% and Mg#
value of 51.7. The MG chondrite-nor mal ized pat tern shows dis - tinctly lower frac tion ation of LREE than in pre vi ous sam ples, with (La/Yb)N ra tio of 2.24, and a dis tinct neg a tive Eu anom aly (Eu/Eu* = 0.4).
On a to tal al kali ver sus sil ica (TAS) di a gram, the sam ples ana lysed plot mostly in the gran ite field and show subalkaline af fin ity (Fig. 8A). The nor ma tive com po si tions are plot ted on a nor ma tive Ab-An-Or di a gram (O’Connor, 1965) which cor rob o - Fig. 6. 40Ar-39Ar ap par ent age spec tra for the Jawornik granitoids
WMPA – weighted mean pla teau age, TFA – to tal fu sion age, IIA – in verse isochron age
rates their gra nitic char ac ter (Fig. 8D). Only a few MBG sam - ples fall in the trondhjemite field (Fig. 8D). On a mo lar Al2O3/(CaO + Na2O + K2O) ver sus Al2O3/(Na2O + K2O) di a gram for dif fer ent granitoid va ri et ies (Fig. 8C) HBG sam ples have metaluminous to mildly peraluminous af fin i ties, BMG are mildly peraluminous, BG are mod er ately peraluminous whereas MG are strongly peraluminous. Points on the K2O ver sus SiO2 plot in di cate that the MBG and MG are calc-al ka line with mod er ate po tas sium con tent while the HBG and BG are calc-al ka line with a high con tent of po tas sium (Fig. 8B). Na2O + K2O con tent,
rang ing from 5.8 to 9.2 wt.%, and Na2O/ K2O ra tios of 1.05 to 3.56, are con sis tent with orogenic granitoid rocks (ac cord ing to Maniar and Piccoli, 1989).
On Harker di a grams (Fig. 9), there are strong neg a tive cor - re la tions be tween SiO2 and CaO, MgO and Fe2O3
t and weaker pos i tive cor re la tions with Na2O and K2O, im ply ing de crease in calcic and ferro mag nesi an min er als and in crease in al kali feld - spar with in creas ing sil ica con tent. In part, this may be due to plagioclase and K-feld spar frac tion ation. How ever, the lack of lin ear trends on a An-Ab-Or ter nary plot give the im pres sion that Fig. 7A – chondrite-nor mal ized REE pat terns (af ter Boynton, 1984);
B – prim i tive man tle-nor mal ized trace el e ment dis tri bu tion pat terns (McDonough and Sun, 1995) for the Jawornik granitoids
the chem i cal vari abil ity of the Jawornik granitoids is not purely gov erned by plagioclase frac tion ation. Well-de fined neg a tive anom a lies for Ba, P and Ti (Fig. 7B) may be re lated to the frac - tion ation of K-feld spar, ap a tite, il men ite and sphene (Bea, 1996). Pre cip i ta tion of ac ces sory min er als such as ap a tite and Fe-Ti ox ides may be also re spon si ble for the de crease in P2O5
and TiO2 with in creas ing SiO2 con tent. The de crease in light and mid dle rare earth el e ments is prob a bly due to frac tion ation of ap a tite as shown by the sim i lar de crease in P2O5. The de ple - tion in HREE may also be due to frac tion ation of zir con, which is sup ported by the de crease in Zr from HBG to MG gran ites (Fig.
10). The de crease in LREE from HBG to BMG is mainly at trib - uted to frac tion ation of al la nite, sphene and monazite. Sam ples
of HBG and BMG are high-K calc-al ka line rocks, show ing de - pleted HREE pat terns which may sug gest the pres ence of gar - net in the res i due (Defant and Drummond, 1990; Rapp and Wat son, 1995). Fur ther more, the rel a tively flat heavy REE pat - terns sug gest that am phi bole was dom i nant rather than gar net in the res i due (Moyen, 2009). The strong neg a tive Nb and Ti anom a lies and de ple tion in Ta sug gests that the source might have been rich in am phi bole and/or rutile. How ever, the low Nb/Ta ra tios (5.83–9.02 for HBG and 4.95–9.06 for BG) points to a rutile-free but am phi bole dom i nant source in the res i due.
The ab sence of sig nif i cant Eu anom a lies and rel a tively high Sr con tents seems to in di cate that plagioclase was not a dom i nant phase in the res i due. Com pared with the HBG, BG and MBG, Fig. 8. Ma jor el e ment di a grams for the Jawornik granitoids
A – TAS di a gram (af ter La Maitre et al., 2002), B – K2O ver sus SiO2 (af ter Peccerillo and Tay lor, 1976), C – A/NK ver sus A/CNK di a gram (af ter Maniar and Piccoli, 1989), D – An-Ab-Or (af ter O`Connor, 1965)
the MG show a stron ger neg a tive Eu/Eu* anom aly, lower Sr/Nd value and lower abun dances of Sr, sug gest ing a greater amount of feld spar (plagioclase) in their res i dues dur ing magma seg re ga tion.
DISCUSSION
Granitoid melts can be form by var i ous pro cesses, in clud ing anatexis of suit able source rocks, frac tional crys tal li za tion, magma mix ing or min gling. How ever, the po si tion of the Jawornik granitoids sills among the coun try rocks, their size, lack of mafic en claves and co eval mafic rocks in di cate that they
may have formed by par tial melt ing, rather than by as sim i la - tion-frac tional crys tal li za tion or magma mix ing. As noted above, the Jawornik granitoids are peraluminous to metaluminous. Liq - uids with such a com po si tion have been pro duced ex per i men - tally by par tial melt ing of var i ous source rocks over a wide range of tem per a tures and pres sures (e.g., Rapp and Wat son, 1995;
Stevens et al., 1997; Altherr and Siebel, 2002). The compo - sitional vari a tions in ex per i men tally ob tained glasses vary as a func tion of com po si tion of source rocks, tem per a ture and pres - sure of melt ing, and wa ter and fluid con tent of the start ing ma te - rial. Ex per i ments have shown that in peraluminous gran ites de - rived from plagioclase-poor and clay-rich metapelitic rocks, the CaO/Na2O ra tio is sig nif i cantly lower (<0.3) and Rb/Ba ra tio higher than in those sourced from plagioclase-rich and clay- Fig. 9. Harker plots for ma jor el e ments for the Jawornik granitoids
poor metapsammitic and metaigneous rocks (Sylvester, 1998).
The Jawornik granitoids ex hibit rel a tively high CaO/Na2O ra tios (0.24–0.67, mean = 0.43) and low Rb/Ba (0.1–0.43, mean = 0.19) ra tios, and plot within the re gion of clay-poor meta - greywacke source rocks (Fig. 11A). In fer ences of the na ture of the source rocks can be de duced from a di a gram (Fig. 11B) adapted af ter Patiño Douce (1999), with de noted fields for magma de rived from fel sic pelites, mafic pelites and grey - wackes. Many of the Jawornik sam ples plot in the greywacke and mafic pelite field, but sev eral sam ples have val ues be yond those of greywacke/mafic pelite par tial melts, re quir ing more prim i tive source rocks. Rapp and Wat son (1995) stated that granitoid melts formed by dehydratation melt ing of am phi bo lites could pos sess sim i lar geo chem i cal char ac ter is tics to melts formed by melt ing of greywackes or mafic pelites. The REE pat - terns (Fig. 7A) of the Jawornik granitoids strongly sug gests that am phi bole was an abun dant phase in the res i due. In deed, am - phi bole is pres ent in re sid ual as sem blages co ex ist ing with granitoid melts af ter par tial melt ing of am phi bo lites at pres sures from 7 to 16 kbars (Rapp and Wat son, 1995 and fur ther ref er - ences there). This state ment is valid for the HBG, BG and MBG
va ri et ies, but not for the MG. Geo chem i cal char ac ter is tics of the MG are dis tinc tive in all im por tant pa ram e ters – strongly peraluminous, with sig nif i cantly lower Mg# ra tio, and lower REE con cen tra tions. Zir cons char ac ter is tic of this va ri ety (GJ44) are also sig nif i cantly dif fer ent com pared to HBG zir cons. The MG geo chem i cal fea tures sug gest that they are de rived from a more fel sic source. Low ini tial eNd val ues, and high ini tial
87Sr/86Sr for the Jawornik granitoids shown by Jastrzêbski et al.
(2018) were in ter preted by these au thors as in di ca tors of their or i gin by par tial melt ing of the lower crust, which is con sis tent with the above ob ser va tions.
Ac cord ing to Štipská et al. (2004), Skrzypek et al. (2011a), and Cho pin et al. (2012b) three main de for ma tion events are re - corded in the OSD. Sam ple GJ117 co mes from the vein which is par al lel to the old est fo li a tion and the age ob tained from this sam ple (351 ±1.3 Ma) cor re lates well with the Pb-Pb zir con evap o ra tion age of 353 ±1 Ma pro vided by Skrzypek et al.
(2014) from the same rock va ri ety. It is also in a good agree - ment with the U-Pb zir con age from sam ple OS399 re ported by Jastrzêbski et al. (2018), which was dis carded by the au thors as be ing 12 My older than the ages from the rest of their sam ples.
66 68 70 72 74 76
050100150200
SiO2
Cr
66 68 70 72 74 76
020406080100
SiO2
Ni
66 68 70 72 74 76
50100150200250
SiO2
Rb
66 68 70 72 74 76
0100300500700
SiO2
Sr
66 68 70 72 74 76
510152025
SiO2
Y
66 68 70 72 74 76
050100150200
SiO2
Zr
66 68 70 72 74 76
20060010001400
SiO2
Ba
66 68 70 72 74 76
510152025303540
SiO2
La
66 68 70 72 74 76
1020304050607080
SiO2
Ce
66 68 70 72 74 76
0.91.01.11.21.31.41.5
SiO2
ACNK
66 68 70 72 74 76
0.20.40.60.81.0
SiO2 K2ONa2O
66 68 70 72 74 76
3540455055606570
SiO2
mg
[wt.%]
[wt.%] [wt.%] [wt.%] [wt.%]
[wt.%]
[ppm] [ppm] [ppm] [ppm]
[ppm] [ppm] [ppm] [ppm]
[ppm]
[wt.%] [wt.%] [wt.%]
[wt.%] [wt.%] [wt.%]
Fig. 10. Harker plots for se lected trace el e ments and chem i cal pa ram e ters for the Jawornik granitoids
A sim i lar age was also ob tained from zir cons from a diorite in the neigh bour ing K³odzko-Z³oty Stok Pluton (Jokubauskas et al., 2018). Ar-Ar dat ing of hornblende and bi o tite from sam ple
GJ117 gave ages sim i lar to those from zir con dat ing (351.1
±3.7 and 349.6 ±3.8 Ma, re spec tively). Over lap of U-Pb and
40Ar-39Ar ages sug gests that the HBG were emplaced at a rel a - tively shal low crustal level. A com par i son of the Ar-Ar am phi - bole with the bi o tite age in di cates a dif fer ence in the time of clo - sure of 1.5 + –3.8 My. Be cause the dif fer ence of the clo sure tem per a ture of Ar-Ar sys tem in am phi bole and bi o tite is as - sumed to be ~200°C, this may cor re spond to cool ing rates of 38–200°C/My for the tem per a ture in ter val be tween 500 and 300°C. Such rapid cool ing rates are char ac ter is tic of rapid tec - tonic up lift as so ci ated with orogenic col lapse. The con cordia age for the MG (336.3 ±2.4 Ma), based on 3 points only, is not sta tis ti cally sig nif i cant (Fig. 5G, H), but sim i lar ages (333 ±4 Ma) were re ported by Jastrzêbski et al (2018) for the BMG va ri ety.
This zir con age noted by Jastrzêbski et al (2018) con flicts with Ar-Ar ages for bi o tite (343.1 ±3.8 Ma) and mus co vite (344.6
±3.8 Ma) from sam ple GJ78b as well as monazite ages (343 ±4 Ma) from the same rock va ri ety (Budzyñ and Jastrzêbski, 2016). Jastrzêbski et al (2018) stated, that in the case of the BMG va ri ety, Ar-Ar cool ing ages and monazite ages better match the crys tal li za tion age. The BMG and BG va ri et ies were in jected par al lel to the main subvertical fo li a tion, so they are older than the MG which cross-cut this fo li a tion. It is pos si ble there fore that zir con ages re ported from the BMG do not re flect the crys tal li za tion age and they may re flect a re cord of a youn - ger, ~335 Ma, ther mal ep i sode. The pres ence of such a mag - matic ep i sode of this age in cen tral Sudetes has also in di cated by zir con ages from rocks of the ad ja cent K³odzko-Z³oty Stok Pluton (Mikulski et al., 2013; Oberc-Dziedzic et al., 2015;
Jastrzêbski et al., 2018; Jokubauskas et al., 2018).
CONCLUSIONS
1. SHRIMP zir con U-Pb ages and Ar-Ar cool ing ages data in di cate that sills of the Jawornik granitoids were emplaced in three main ep i sodes:
–~350 Ma – in tru sion of the HBG par al lel to the S1 fo li a tion;
–~344 Ma – in jec tion of the BG and BMG (main vein) par al lel to S2;
–~335 Ma (?) – in tru sion of MG cross-cut ting S2.
2. Geo chem i cal data from the Jawornik granitoids may in di - cate that they were most prob a bly de rived through par tial melt - ing of two dif fer ent sources:
–the HBG, BG and BMG va ri et ies were formed by melt ing of a crustal source orig i nally con sist ing of metagreywackes, with pos si ble ad mix tures of mafic pelites or/and am phi bo - lites;
–the MG va ri ety was sourced from more fel sic, plagioclase - -rich and clay-poor rocks.
Ac knowl edge ments. The jour nal re view ers, B. Bagiñski and M. Jastrzêbski, are thanked for help ful re marks.
REFERENCES
Aleksandrowski, P., Mazur, S., 2002. Col lage tec ton ics in the northeasternmost part of the Variscan Belt: the Sudetes, Bo he - mian Mas sif. Geo log i cal So ci ety Spe cial Pub li ca tions, 201:
37–277.
Altherr, R., Siebel, W., 2002. I-type plutonism in a con ti nen tal back-arc set ting: Mio cene granitoids and monzonites from the cen tral Aegean Sea, Greece. Con tri bu tions to Min er al ogy and Pe trol ogy, 143: 397–415.
Fig. 11A – Rb/Sr ver sus Rb/Ba with mix ing curve be tween the ba salt and pelite-de rived melts (af ter Sylvester, 1998); B – Na2O + K2O + FeOT + MgO + TiO2 ver sus (Na2O + K2O)/( FeOT + MgO + TiO2) with com po si tions of melts pro duced by ex per i men tal dehydratation -melt ing of var i ous meta-sed i men tary rocks (af - ter Patino Douce, 1999)
HP – high-pres sure; LP – low-pres sure
Bea, F., 1996. Res i dence of REE, Y, Th and U in gran ites and crustal protoliths; im pli ca tions for the chem is try of crustal melts. Jour - nal of Pe trol ogy, 37: 521–552.
Bederke, E., 1929. Die Grenze von Ost- und Westsudeten und ihre Bedeutung für die Einordnung der Sudeten in den Gebirgsbau Mitteleuropas. Geologische Rundschau, 20: 186–205.
Bia³ek, D., 2003. Pe trog ra phy and geo chem is try of the Jawornickie granitoids, West Sudetes. Min er al og i cal So ci ety of Po land – Spe cial Pa pers, 22: 22–24.
Bia³ek, D., 2014. SHRIMP U–Pb zir con geo chron ol ogy of the Jawornik granitoids (West Sudetes, Po land). Geologia Sudetica, 42: 4.
Bia³ek, D., Werner, T., 2002. AMS and de for ma tion pat terns in the Jawornickie Granitoids, Rychlebske Hory – pre lim i nary data.
Geolines, 14: 14–15.
Bia³ek, D., Werner, T., 2004. Geo chem is try and geo chron ol ogy of the Javornik granodiorite and its geodynamic sig nif i cance in the East ern Variscan Belt. Geolines, 17: 22–23.
Boynton, W.V., 1984. Cosmochemistry of the Rare Earth El e ments:
me te or ite stud ies. De vel op ments in Geo chem is try, 2: 63–114.
Bröcker, M., Klemd, R., Cosca, M., Brock, W., Larionov, A.N., Rodionov, N., 2009. The tim ing of eclogite fa cies meta mor - phism and migmatization in the Orlica-Œnie¿nik com plex, Bo he - mian Mas sif: con straints from a multimethod geo chron ol ogi cal study. Jour nal of Meta mor phic Ge ol ogy, 27: 385–403.
Budzyñ, B., Jastrzêbski, M., 2016. Monazite sta bil ity and the main - te nance of Th-U-to tal Pb ages dur ing post-mag matic pro cesses in granitoids and host metasedimentary rocks: a case study from the Sudetes (SW Po land). Geo log i cal Quar terly, 60 (1):
106–123.
Burchart, J., 1958. On the Jawornik granitoids (East ern Sudeten) (in Pol ish with Eng lish sum mary). Archiwum Mineralogiczne, 22: 237–348.
Cho pin, F., Schulmann, K., Skrzypek, E., Lehmann, J., Dujardin, J.R., Martelat, J.E., Lexa, O., Corsini, M., Edel, J.B., Štípská, P., Pitra, P., 2012a. Crustal in flux, in den ta tion, duc tile thin ning and grav ity re dis tri bu tion in a con ti nen tal wedge: build ing a Moldanubian man tled gneiss dome with underthrust Saxo - thuringian ma te rial (Eu ro pean Variscan belt): orogenic wedge and gneiss dome for ma tion. Tec ton ics, 31: 1–27.
Cho pin, F., Schulmann, K., Štípská, P., Martelat, J.E., Pitra, P., Lexa, O., Petri, B., 2012b. Microstructural and meta mor phic evo lu tion of a high-pres sure gra nitic orthogneiss dur ing con ti - nen tal subduction (Orlica-Œnie¿nik dome, Bo he mian Mas sif):
de for ma tion of HP gra nitic orthogneiss. Jour nal of Meta mor phic Ge ol ogy, 30: 347–376.
Cloos, H., 1922. Der Gebirgsbau Schlesiens und die Stellung seiner Bodenschätze. Verlag von Gebrüder Borntraeger, Berlin.
Compston, W., Wil liams, I.S., Meyer, C., 1984. U-Pb geo chron ol - ogy of zir cons from lu nar brec cia 73217 us ing a sen si tive high mass-res o lu tion ion microprobe. Jour nal of Geo phys i cal Re - search, 89: B525.
Cwojdziñski, S., 1977. The re la tion of Jawornik granitoids to de for - ma tion of L¹dek-Œnie¿nik meta mor phic area (in Pol ish with Eng lish sum mary). Geo log i cal Quar terly, 21 (3): 451–465.
Cwojdziñski, S., 1979. Szczegó³owa mapa geologiczna Sudetów w skali 1:25 000, arkusz Trzebieszowice (in Pol ish). Wyd. Geol., Warszawa.
Cymerman, Z., 1996. The Zloty Stok-Trzebieszowice re gional shear zone: the bound ary of ter ranes in the Góry Z³ote Mts.
(Sudetes). Geo log i cal Quar terly, 40 (1): 89–118.
Cymerman, Z., Piasecki, M.A.J., Seston, R., 1997. Ter ranes and terrane bound aries in the Sudetes, north east Bo he mian Mas sif.
Geo log i cal Mag a zine, 134: 717–725.
Defant, M.J., Drummond, M.S., 1990. Der i va tion of some mod ern arc mag mas by melt ing of young subducted litho sphere. Na ture, 347: 662–665.
Don, J., 1964. The Z³ote and Krowiarki Moun tains as struc tural el e - ments of the Œnie¿nik meta mor phic mas sif (in Pol ish with Eng - lish sum mary). Geologia Sudetica, 1: 79–117.
Don, J., Dumicz, M., Wojciechowska, I., ¯elaŸniewicz, A., 1990.
Lihology and tec ton ics of the Orlica-Œnie¿nik Dome, Sudetes:
re cent state of knowl edge. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen, 179: 159–188.
Don, J., Skácel, J., Gotowa³a, R., 2003. The bound ary zone of the East and West Sudetes on the 1:50 000 scale geo log i cal map of the Velké Vrbno, Staré Mesto and Œnie¿nik Meta mor phic Units.
Geologia Sudetica, 35: 25–39.
Dumicz, M., 1979. Tectogenesis of the meta mor phosed se ries of the K³odzko dis trict: a ten ta tive ex pla na tion. Geologia Sudetica, 14: 29–44.
Finckh, L., Meister, F., Fischer, G., Bederke, E., 1942. Geolo - gische Karte des deutschen Reiches 1:25 000. Blatt Glatz, Konigshein, Reichenstein und Landeck. Erlautemgen, Berlin.
Fischer, G., 1936. Der Bau des Glatzer Schneegebirges. Jahrbuch der Preußischen Geologischen Landesanstalt, 56: 712–732.
Franke, W., 2000. The mid-Eu ro pean seg ment of the Variscides:
tectonostratigraphic units, terrane bound aries and plate tec tonic evo lu tion. Geo log i cal So ci ety Spe cial Pub li ca tions, 179: 35–61.
Franke, W., ¯elaŸniewicz, A., 2002. Struc ture and evo lu tion of the Bo he mian Arc. Geo log i cal So ci ety Spe cial Pub li ca tions, 201:
279–293.
Janoušek, V., Far row, C.M., Erban, V., 2006. In ter pre ta tion of whole-rock geo chem i cal data in ig ne ous geo chem is try: in tro - duc ing geo chem i cal data toolkit (GCDkit). Jour nal of Pe trol ogy, 47: 1255–1259.
Jastrzêbski, M., 2009. A Variscan con ti nen tal col li sion of the West Sudetes and the Brunovistulian terrane: a con tri bu tion from struc tural and meta mor phic re cord of the Stronie For ma tion, the Orlica-Œnie¿nik Dome, SW Po land. In ter na tional Jour nal of Earth Sci ences, 98: 1925–1925.
Jastrzêbski, M., ¯elaŸniewicz, A., Nowak, I., Murtezi, M., Larionov, A.N., 2010. Protolith age and prov e nance of meta - sedimentary rocks in Variscan allochthon units: U–Pb SHRIMP zir con data from the Orlica–Œnie¿nik Dome, West Sudetes.
Geo log i cal Mag a zine, 147: 416–433.
Jastrzêbski, M., ¯elaŸniewicz, A., Majka, J., Murtezi, M., Bazarnik, J., Kapitonov, I., 2013. Con straints on the De vo - nian–Car bon if er ous clo sure of the Rheic Ocean from a multi- method geo chron ol ogy study of the Staré Mìsto Belt in the Sudetes (Po land and the Czech Re pub lic). Lithos, 170–171:
54–72.
Jastrzêbski, M., Machowiak, K., Krzemiñska, E., Lang Farmer, G., Larionov, A.N., Murtezi, M., Majka, J., Sergeev, S., Ripley, E.M., Whitehouse, M., 2018. Geo chron ol ogy, petro gen esis and geodynamic sig nif i cance of the Visean ig ne ous rocks in the Cen tral Sudetes, north east ern Bo he mian Mas sif. Lithos, 316–317: 385–405.
Jokubauskas, P., Bagiñski, B., Mac don ald, R., Krzemiñska, E., 2018. Multiphase mag matic ac tiv ity in the Variscan K³odzko - -Z³oty Stok in tru sion, Pol ish Sudetes: ev i dence from SHRIMP U-Pb zir con ages. In ter na tional Jour nal of Earth Sci ences, 107:
1623–1639.
Ken nedy, A.K., de Laeter, J.R., 1994. The per for mance char ac ter - is tics of the WA SHRIMP II ion microprobe. Eighth In ter na tional Con fer ence on Geo chron ol ogy, Cosmochronology and Iso tope Ge ol ogy. Berke ley, USA. Ab stracts Vol., U.S 1107: 166.
Koz³owska-Koch, M., 1973. Polymetamorphites of the Z?oty Stok
— Skrzynka Dis lo ca tion Zone (in Pol ish with Eng lish sum mary).
Geologia Sudetica, 8: 121–160.
Kryza, R., Pin, C., Oberc-Dziedzic, T., Crowley, Q.G., Larionov, A., 2014. De ci pher ing the geo chron ol ogy of a large granitoid pluton (Karkonosze Gran ite, SW Po land): an as sess ment of U–Pb zir con SIMS and Rb–Sr whole-rock dates rel a tive to U–Pb zir con CA-ID-TIMS. In ter na tional Ge ol ogy Re view, 56:
756–782.
Lange, U., Bröcker, M., Armstrong, R., ZelaŸniewicz, A., Trapp, E., Mezger, K., 2005. The orthogneisses of the Orlica–Œnie¿nik com plex (West Sudetes, Po land): geo chem i cal char ac ter is tics, the im por tance of pre-Variscan migmatization and con straints on the cool ing his tory. Jour nal of the Geo log i cal So ci ety, 162:
973–984.
Laurent, A., Janoušek, V., Magna, T., Schulmann, K., Míková, J., 2014. Petro gen esis and geo chron ol ogy of a post-orogenic
calc-al ka line mag matic as so ci a tion: the Žulová Pluton, Bo he - mian Mas sif. Jour nal of Geosciences, 59: 415–440.
Le Maitre, R.W., Streckeisen, A., Zanettin, B., Le Bas, M.J., Bonin, B., Bate man, P., Bellieni, G., Dudek, A., Efremova , S., Keller, J., Lamere, J., Sabine, P.A., Schmid, R., Sorensen, H., Woolley, A.R., 2002. Ig ne ous Rocks: a Classifcation and Glos - sary of Terms, Rec om men da tions of the In ter na tional Un ion of Geo log i cal Sci ences, Subcommission of the Sys tem at ics of Ig - ne ous Rocks. Cam bridge Uni ver sity Press, Cam bridge, UK.
Lud wig, K.R., 2003. Isoplot 3.0. A Geo chron ol ogi cal Toolkit for Microsoft Ex cel. Berke ley Geochron, Cen ter Spe cial Pub li ca - tion, 4.
Lud wig, K.R., 2009. SQUID II., a user’s man ual. Berke ley Geo - chron ol ogy Cen ter Spe cial Pub li ca tion, 2455 Ridge Road, Berke ley, CA 94709, USA 22. 2.
Maniar, P.D., Piccoli, P.M., 1989. Tec tonic dis crim i na tion of granitoids. GSA Bul le tin, 101: 635–643.
Matte, Ph., Maluski, H., Rajlich, P., Franke, W., 1990. Terrane bound aries in the Bo he mian Mas sif: re sult of large-scale Variscan shear ing. Tectonophysics, 177: 151–170.
Mazur, S., Aleksandrowski, P., Kryza, R., Oberc-Dziedzic, T., 2006. The Variscan Orogen in Po land. Geo log i cal Quar terly, 50 (1): 89–118.
Mazur, S., Szczepañski, J., Turniak, K., McNaughton, N.J., 2012.
Lo ca tion of the Rheic su ture in the east ern Bo he mian Mas sif:
ev i dence from de tri tal zir con data: lo ca tion of Rheic su ture in east ern Bo he mian Mas sif. Terra Nova, 24: 199–206.
Mazur, S., Turniak, K., Szczepañski, J., McNaughton, N.J., 2015.
Ves tiges of Saxothuringian crust in the Cen tral Sudetes, Bo he - mian Mas sif: zir con ev i dence of a re cy cled subducted slab prov - e nance. Gond wana Re search, 27: 825–839.
McDonough, W.F., Sun, S.-S., 1995. The com po si tion of the Earth.
Chem i cal Ge ol ogy, 120: 223–253.
Mikulski, S.Z., Wil liams, I.S., Bagiñski, B., 2013. Early Car bon if - er ous (Viséan) em place ment of the collisional K³odzko–Z³oty Stok granitoids (Sudetes, SW Po land): con straints from geo - chem i cal data and zir con U-Pb ages. In ter na tional Jour nal of Earth Sci ences, 102: 1007–1027.
Moyen, J.-F., 2009. High Sr/Y and La/Yb ra tios: the mean ing of the
“adakitic sig na ture.” Lithos, 112: 556–574.
Murtezi, M., 2006. The acid metavol ca nic rocks of the Orlica - -Œnie¿nik Dome (Sudetes): their or i gin and tectono-meta mor - phic evo lu tion. Geologia Sudetica, 38: 1–38.
Nemec, D., 1951. Petrografie javornického masivu a žilných hornin s ním sdružených (in Czech). I. Pøírodovedecký Sbornik Ostravského Kraje, 12: 289–304.
O’Connor, J.T., 1965. A clas si fi ca tion of quartz rich ig ne ous rock based on feld spar ra tios. US Geo log i cal Sur vey, 525B:
B79–B84.
Oberc-Dziedzic, T., Kryza, R., 2012. Late stage Variscan magma - tism in the Strzelin Mas sif (SW Po land): SHRIMP zir con ages of tonalite and Bt-Ms gran ite of the Gêsiniec in tru sion. Geo log i cal Quar terly, 56 (2): 25–236.
Oberc-Dziedzic, T., Kryza, R., Pin, C., 2015. Variscan granitoids re lated to shear zones and faults: ex am ples from the Cen tral Sudetes (Bo he mian Mas sif) and the Mid dle Odra Fault Zone. In - ter na tional Jour nal of Earth Sci ences, 104: 1139–1166.
Parry, M., Štípská, P., Schulmann, K., Hrouda, F., Ježek, J., Kröner, A., 1997. Tonalite sill em place ment at an oblique plate bound ary: north east ern mar gin of the Bo he mian Mas sif.
Tectonophysics, 280: 61–81.
Patiño Douce, A.E., 1999. What do ex per i ments tell us about the rel a tive con tri bu tions of crust and man tle to the or i gin of gra nitic mag mas? Geo log i cal So ci ety Spe cial Pub li ca tions, 168: 55–75.
Peccerillo, A., Tay lor, S.R., 1976. Geo chem is try of eocene calc-al - ka line vol ca nic rocks from the Kastamonu area, North ern Tur - key. Con tri bu tions to Min er al ogy and Pe trol ogy, 58: 63–81.
Pietranik, A., Storey, C., Kierczak, J., 2013. The Niemcza diorites and moznodiorites (Sudetes, SW Po land): a re cord of chang ing
geotectonic set ting at ca. 340 Ma. Geo log i cal Quar terly, 57 (2):
325–334.
Rapp, R.P., Wat son, E.B., 1995. De hy dra tion melt ing of metabasalt at 8-32 kbar: im pli ca tions for con ti nen tal growth and crust-man - tle re cy cling. Jour nal of Pe trol ogy, 36: 891–931.
Schulmann, K., Gayer, R., 2000. A model for a con ti nen tal accretio - nary wedge de vel oped by oblique col li sion: the NE Bo he mian Mas sif. Jour nal of the Geo log i cal So ci ety, 157: 401–416.
Schulmann, K., Lexa, O., Janoušek, V., Lardeaux, J.M., Edel, J.B., 2014. Anat omy of a dif fuse cryp tic su ture zone: an ex am - ple from the Bo he mian Mas sif, Eu ro pean Variscides. Ge ol ogy, 42: 275–278.
Skrzypek, E., Štípská, P., Schulmann, K., Lexa, O., Lexová, M., 2011a. Prograde and ret ro grade meta mor phic fab rics – a key for un der stand ing burial and ex hu ma tion in orogens (Bo he mian Mas sif): prograde and ret ro grade fab rics. Jour nal of Meta mor - phic Ge ol ogy, 29: 451–472.
Skrzypek, E., Schulmann, K., Štípská, P., Cho pin, F., Lehmann, J., Lexa, O., Haloda, J., 2011b. Tectono-meta mor phic his tory re corded in gar net porphyroblasts: in sights from ther mo dy namic mod el ling and elec tron back scat ter dif frac tion anal y sis of in clu - sion trails: tectono-meta mor phic his tory in porphyroblasts. Jour - nal of Meta mor phic Ge ol ogy, 29: 473–496.
Skrzypek, E., Lehmann, J., Szczepañski, J., Anczkiewicz, R., Štípská, P., Schulmann, K., Kröner, A., Bia³ek, D., 2014.
Time-scale of de for ma tion and intertectonic phases re vealed by P-T-D-t re la tion ships in the orogenic mid dle crust of the Orlica-Œnie¿nik Dome, Pol ish/Czech Cen tral Sudetes. Jour nal of Meta mor phic Ge ol ogy, 32: 981–1003.
Stevens, G., Clem ens, J.D., Droop, G.T.R., 1997. Melt pro duc tion dur ing granulite-fa cies anatexis: ex per i men tal data from “prim i - tive” metasedimentary protoliths. Con tri bu tions to Min er al ogy and Pe trol ogy, 128: 352–370.
Štípská, P., Schulmann, K., Kröner, A., 2004. Ver ti cal ex tru sion and mid dle crustal spread ing of omphacite granulite: a model of syn-con ver gent ex hu ma tion (Bo he mian Mas sif, Czech Re pub - lic): granulite ex tru sion and spread ing. Jour nal of Meta mor phic Ge ol ogy, 22: 179–198.
Štípská, P., Cho pin, F., Skrzypek, E., Schulmann, K., Pitra, P., Lexa, O., Martelat, J.E., Bol linger, C., Žáèková, E., 2012. The jux ta po si tion of eclogite and mid-crustal rocks in the Orlica - -Œnie¿nik Dome, Bo he mian Mas sif: jux ta pos ing eclogite and mid-crustal rocks. Jour nal of Meta mor phic Ge ol ogy, 30:
213–234.
Sylvester, P.J., 1998. Post-collisional strongly peraluminous gran - ites. Lithos, 45: 29–44.
Turniak, K., Mazur, S., Wysoczanski, R., 2000. SHRIMP zir con geo chron ol ogy and geo chem is try of the Orlica-Œnie¿nik gneiss - es (Variscan belt of Cen tral Eu rope) and their tec tonic im pli ca - tions. Geodinamica Acta, 13: 293–312.
Turniak, K., Mazur, S., Domañska-Siuda, J., Szuszkiewicz, A., 2014. SHRIMP U-Pb zir con dat ing for granitoids from the Strzegom–Sobótka Mas sif, SW Po land: con straints on the ini tial time of Permo-Me so zoic litho sphere thin ning be neath Cen tral Eu rope. Lithos, 208–209: 415–429.
Wil liams, I.S., 1998. U-Th-Pb geo chron ol ogy by ion microprobe.
Re views in Eco nomic Ge ol ogy, 7: 1–35.
Závada, P., Calassou, T., Schulmann, K., Štípská, P., Hasalová, P., Míková, J., Magna, T., Mixa, P., 2017. Mag netic fab ric trans - po si tion in folded gran ite sills in Variscan orogenic wedge. Jour - nal of Struc tural Ge ol ogy, 94: 166–183.
Žák, J., Verner, K., Janoušek, V., Holub, F.V., Kachlík, V., Fin ger, F., Hajná, J., Tomek, F., Vondrovic, L., Trubaè, J., 2014. A plate-ki ne matic model for the as sem bly of the Bo he mian Mas sif con strained by struc tural re la tion ships around granitoid plutons.
Geo log i cal So ci ety Spe cial Pub li ca tions, 405: 169–196.
¯elaŸniewicz, A., Nowak, I., Larionov, A., Presnyakov, S., 2006.
Syntectonic Lower Or do vi cian migmatite and post-tec tonic Up - per Visean syenite in the west ern limb of the Orlica–Œnie¿nik Dome, West:U-Pb SHRIMP data from zir cons. Geologia Sudetica, 38: 63–80.
