摘要
文中分析了中生代大型、超大型火山岩型铀矿床产出的特异部位──含矿火山塌（断）陷的地质环境，将其归纳为＂近带、伴盆、早洼、晚隆、切壳、酸底、泥化＂１４字特征。在讨论该类铀矿床的形成机制的基础上，提出了特异部位的９条定位标志，即：位处１，２级构造单元结合部位的构造岩浆活动带；构造岩浆活动带边部的大型火山沉积盆地；火山沉积盆地边部的港湾状小型火山塌（断）陷；火山塌（断）陷的火山岩发育充分；火山塌（断）陷在盆地发展晚期隆起；火山塌（断）陷受一条长期活动的切壳断裂控制；火山塌（断）陷的基底发育有多期花岗岩体；火山塌（断）陷的盖层遭受强烈的以泥化为主的中低温蚀变作用；蚀变带有硅化、低温钠长石化、铁绿泥石化等蚀变作用叠加，并见有铀及其相关元素异常。
This paper analyses the specific positions for Mesozoic large and superlarge volcanictype uranium deposits──geological environment of uranium-bearing volcanic collaspe(downfaulting) basin,which are characterized by being adjacent to the regional tectono-magmatic belt,accompanied with sedimentary basin,formed in the early stage of volcanic depression,uplifted in the late stage of basin development,cut by crustal faults,underlain by acidicrock basement and accompanied by extensive argillation. On the basis of discussing the formational mechanism of this type of uranium deposit,nine location criteria for the specific positions are proposed, namely: mobile tectono-magmatic zone at the intersection of the firstand second order tectonic elements;large sized volcano-sedimentary basin at the margin ofmobile tectono-magmatic zone;small sized embayed volcanic collaspe (downfaulting) basin atthe margin of volcano-sedimentary basin;well-developed volcanic rocks in volcanic collaspe(downfaulting)basin;uplifting of volcanic collaspe (downfaulting)basin in the later stage ofbasin development; volcanic collaspe (downfaulting)basin controlled by a crustal fault withlong-term activities;multiple phases of granitic massif developed in the basement of volcaniccollapse (downfaulting)basin; cover of volcanic collapse(downfaulting) basin underwent intense moderate-low temperature volume alteration(mainly as argillation);volume alterationis superimposed by silicification,low temperature albition,ferrichloritization and anomaliesof uranium and associated elements are encountered.
出处
《铀矿地质》
CSCD
北大核心
1994年第5期275-284,共10页
Uranium Geology
关键词
铀矿床
火山岩型
地质构造
圈定
Superlarge uranium deposit
Specific position prediction,Formation mechanism
Location criteria
