Supplemental Material: New constraints on the source of loess from U/Th-Pb geochronology of detrital multi-minerals
0
Citation
36
Reference
10
Related Paper
Abstract:
<p>Geological background of the Chinese Loess Plateau source regions, samples and analytical methods, supplemental Figures S1–S4, and data tables S1–S4. </p>Keywords:
Geochronology
Geochronology
Cite
Citations (2)
Cassiterite
Geochronology
Cite
Citations (13)
盖吉夏铜多金属矿床位于香格里拉地区格咱斑岩带红山-普朗铜多金属成矿亚带北段，铜多金属矿化与石英二长闪长玢岩紧密相关。石英二长闪长玢岩LA-ICP-MS锆石U-Pb年龄为216.6±2.3Ma（MSWD=1.9），与区域上普朗、松诺、地苏嘎、雪鸡坪、春都等含矿斑岩体年龄一致。锆石eHf（t）值分布范围为-1.55~3.27，平均为1.57，分布较集中；单阶段Hf模式年龄（tDM1）变化范围为733~918Ma，平均为795Ma，二阶段Hf模式年龄（tDM2）为923~1178Ma，平均为1015Ma，揭示其源区可能为亏损地幔或新生壳源物质。岩石SiO2为61.08%~69.55%，Na2O+K2O为7.22%~7.82%，Na2O/K2O为0.87~1.87，具高钾钙碱性准铝质-弱过铝质（A/CNK=0.75~1.34）特征，岩石富集轻稀土元素[（La/Yb）N=13.35~24.85]和大离子亲石元素（Rb、Ba、Pb等），相对亏损重稀土元素和高场强元素（Ti、Nb、P等），且具有高Sr（>400×10-6），低Y（< 18×10-6）、Yb（< 1.9×10-6）及高Sr/Y、La/Nb等特点，显示出正常弧岩浆系列钙碱性岩石特征，说明含矿石英二长闪长玢岩与岛弧环境密切相关。这种特征的花岗岩可能为盖吉夏的Cu成矿作用提供了重要的物质来源。
Geochronology
Cite
Citations (0)
Geochronology
δ34S
Isotope Geochemistry
Cite
Citations (20)
We investigated the age and petrology of Paleoproterozoic granitic intrusions in the area of the Kiggavik uranium exploration camp, near the southeast margin of the Aberdeen subbasin of the Thelon Basin. A subset of these intrusions (e.g., the Lone Gull stock) is spatially associated with and mineralized by basement hosted, unconformity-related uranium deposits. Surface (outcrop) samples have field relations, textures, and compositions consistent with Hudson Suite granitoids and mixtures of monzogranite with minette. We obtained U–Pb (zircon) ages ranging from ca. 1818 to 1840 Ma, within the known range of the Hudson Suite and cogenetic minettes of the Baker Lake Group (1.80–1.84 Ga). Core samples of granitic rocks adjacent to mineralized zones are more complex and indicate an influence from the younger Nueltin Granite (Kivalliq Igneous Suite, ca. 1.77–1.73 Ga). One sample from the Lone Gull stock contains two zircon populations in texturally distinctive domains, one at 1806 ± 41 Ma and the other at 1748 ± 9.4 Ma. A porphyritic hypabyssal syenite below the Bong deposit yielded a U–Pb zircon age of 1837.8 ± 7.7 Ma and a U–Pb titanite age of 1758.5 ± 44 Ma. We recognize a Kivalliq-age overprint in the form of metasomatism and partial remelting or melt infiltration in the drill core samples, which is not evident at the surface and is consistent with the presence of a Nueltin Granite intrusive complex at depth. The geochemistry and primary igneous textures of the Bong syenite, including its euhedral zircons, resemble those of lava flows near the base of the Baker Lake Group, and we recognize a mixed magma (i.e., Martell Syenite) continuum between intrusive Hudson granitoids and minette with extrusive equivalents in the lower felsic minette member of the Christopher Island Formation.
Geochronology
Porphyritic
Titanite
Outcrop
Conglomerate
Cite
Citations (22)
Porphyritic
Geochronology
Diorite
Felsic
Fractional crystallization (geology)
Batholith
Cite
Citations (15)
Hypogene
Overprinting
Magmatic water
Ore genesis
Cite
Citations (29)
Massif
Geochronology
Charnockite
Cite
Citations (73)