The dike rocks under study are localized in Mesozoic (T3-J2) clastic rocks in the western part of Verkhoyansk-Kolyma fold area. Studying the nature of the dikes and geodynamic setting of their formation is of great interest now in view of the controversy surrounding their assignment to definite magmatic complexes of the Verkhoyansk-Kolyma fold area and the uncertain origin of mineralization in the Yana-Kolyma gold belt. Major elements were determined using the silicate analysis of magmatic rocks. The mineral compositions of dike rocks were studied using a Tescan MIRA 3 LMU scanning electron microscope. Studies of REE and other trace elements were performed with the use of mass spectrometers - quadrupolar Agilent7500ce (Japan) and high-resolution Element2 (Germany). Their petrologic compositions vary widely including basanite, trachybasalt, andesite, trachyandesite, dacite and granodiorite. The rocks are spatially associated with gold mineralization of the Yana-Kolyma gold belt. Intense secondary alteration of the dikes includes carbonatization, chloritization, pelitization, sericitization, saussuritization, and epidotization. The SiO2 content in the sampled rocks varies from 46.8 to 70.5 wt. %, while the total amount of Na2O+K2O ranges from 2.69 to 7.59 wt. %. The dike rocks belong to the low- and high-K calc-alkaline and the shoshonite magmatic series. They exhibit a uniform REE distribution pattern intermediate between those of OIB and E-MORB. The flat HREE trend is close to that of MORB. The Eu anomaly is absent (0.9-1.0). Positive Ba, K and negative Ti, Ta, and Nb anomalies are observed. Trace element trends are much like those established for mafic rocks from dikes at the Malo-Tarynskoe and Tin-Yuryuete gold deposits in the western part of the Verkhoyansk-Kolyma fold area. The dikes could have formed from mixed enriched and depleted mantle sources, possibly with the involvement of a subduction-related component.
|Журнал||International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM|
|Состояние||Опубликовано - 2020|
|Событие||20th International Multidisciplinary Scientific Geoconference: Science and Technologies in Geology, Exploration and Mining, SGEM 2020 - Albena, Болгария|
Продолжительность: 18 авг 2020 → 24 авг 2020