The Jawornik granitoids intrude, in vein-like form, a sequence of a polymetamorphic metavolcanic and metapelitic rocks of the Orlica-Śnieznik Dome, Sudetes, Poland. This paper provides whole-rock geochemical data, sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon geochronological data as well as 40Ar-39Ar age determinations to constrain the genetic and temporal relationships of the different rock types forming these veins. Based on macroscopically visible features of the granitoids and their relationship with tectonic structures visible in the country rocks, four varieties of the Jawornik granitoids have been distinguished: amphibole- and biotite-bearing granites (HBG), biotite-bearing granites (BG), biotite- and muscovite-bearing granites (BMG) and muscovite-bearing granites (MG). The Jawornik granitoids as a whole show a limited but significant variation in major element chemical composition, with SiO 2 ranging from 65 to 76 wt.% (average 69.16 wt.%, n = 24). They are subalkalic, peraluminous and calc-alkaline [average A/CNK = 1.07, average (Na 2 O + K 2 O) = 7.75, average (Fe 2 O 3 t /(Fe 2 O 3 t + MgO) = 0.59]. Close inspection of their geochemical parameters showed that the samples investigated can be subdivided into two groups. The first group, the HBG, BG, and BMG varieties, comprising most of the granitoids in the Zloty Stok-Skrzynka Tectonic Zone, were formed by melting of greywackes or/and amphibolites. The MG, belonging to the second group, were formed by partial melting of a more felsic source. The HBG yielded a zircon U-Pb age of 351 ±1.3 Ma and well-defined 40 Ar- 39 Ar plateau ages for hornblende (351.1 ±3.9 Ma) and coexisting biotite (349.6 ±3.8 Ma), indicating probably the oldest magmatic event in this region. Zircons from the MG, the youngest rock variety on the basis of their relationship with the tectonic structures in the host rocks, yielded a U-Pb age of 336.3 ±2.4 Ma, though based on three points only. The biotites and muscovites from the BMG have 40 Ar- 39 Ar plateau ages of 344.1 ±4.7 Ma and 344.6 ±3.8 Ma, respectively. These data, in combination with already published isotopic ages, suggest that the Jawornik granitoids intruded host rocks of the Orlica-Śnieznik Dome in three stages, at ~350, ~344 and ~335 Ma.

中文翻译：

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Jawornik 花岗岩的地球化学和地质年代学，Orlica-Śnieżnik Dome，Sudetes，波兰

Jawornik 花岗岩以脉状形式侵入波兰苏台德的 Orlica-Śnieznik Dome 的一系列多变质变质火山和变泥质岩。本文提供了全岩地球化学数据、敏感高分辨率离子微探针 (SHRIMP) U-Pb 锆石年代学数据以及 40Ar-39Ar 年龄测定，以限制形成这些脉的不同岩石类型的成因和时间关系。根据花岗岩的宏观可见特征及其与在围岩中可见的构造结构的关系，Jawornik 花岗岩被区分为四种：含角闪石和黑云母的花岗岩（HBG）、含黑云母的花岗岩（BG）、黑云母- 含白云母花岗岩 (BMG) 和含白云母花岗岩 (MG)。Jawornik 花岗岩作为一个整体显示出主要元素化学成分有限但显着的变化，SiO 2 的范围为 65 至 76 wt.%（平均 69.16 wt.%，n = 24）。它们是亚碱性、过铝和钙碱性 [平均 A/CNK = 1.07，平均 (Na 2 O + K 2 O) = 7.75，平均 (Fe 2 O 3 t /(Fe 2 O 3 t + MgO) = 0.59] . 对其地球化学参数的仔细检查表明，所研究的样品可以细分为两组。第一组，HBG、BG 和 BMG 变种，包括 Zloty Stok-Skrzynka 构造带中的大部分花岗岩，是由熔融形成的greywackes 或/和角闪石。属于第二组的 MG 是由更多长英质源的部分熔化形成的。HBG 产生了 351 ±1.3 Ma 的锆石 U-Pb 年龄和明确的 40 Ar- 39 Ar角闪石的高原年龄 (351.1 ±3. 9 Ma) 和共存的黑云母 (349.6 ±3.8 Ma)，表明可能是该地区最古老的岩浆事件。MG 中的锆石是最年轻的岩石品种，根据它们与主岩构造结构的关系，虽然仅基于三个点，但其 U-Pb 年龄为 336.3 ±2.4 Ma。来自 BMG 的黑云母和白云母具有 40 Ar- 39 Ar 高原年龄分别为 344.1 ±4.7 Ma 和 344.6 ±3.8 Ma。这些数据与已发表的同位素年龄相结合，表明 Jawornik 花岗岩在~350、~344 和~335 Ma 分三个阶段侵入 Orlica-Śnieznik Dome 的主岩。尽管仅基于三个点，但产生了 336.3 ±2.4 Ma 的 U-Pb 年龄。来自 BMG 的黑云母和白云母具有 40 Ar- 39 Ar 高原年龄分别为 344.1 ±4.7 Ma 和 344.6 ±3.8 Ma。这些数据与已发表的同位素年龄相结合，表明 Jawornik 花岗岩在~350、~344 和~335 Ma 分三个阶段侵入 Orlica-Śnieznik Dome 的主岩。尽管仅基于三个点，但产生了 336.3 ±2.4 Ma 的 U-Pb 年龄。来自 BMG 的黑云母和白云母具有 40 Ar- 39 Ar 高原年龄分别为 344.1 ±4.7 Ma 和 344.6 ±3.8 Ma。这些数据与已发表的同位素年龄相结合，表明 Jawornik 花岗岩在~350、~344 和~335 Ma 分三个阶段侵入 Orlica-Śnieznik Dome 的主岩。