Late cretaceous magmatism in the Northern Lhasa subterrane, central Tibet: geodynamic implications

岩浆作用 锆石 地质学 地球化学 地体 白垩纪 地幔(地质学) 部分熔融 玄武岩 岩浆 地质年代学 岩石圈 岩石学 构造学 古生物学 火山
作者
Miao Sun,Wei Chen,Reiner Klemd,Juxing Tang,Xudong Ma,Qingping Liu
出处
期刊:International Geology Review [Informa]
卷期号:65 (10): 1644-1663
标识
DOI:10.1080/00206814.2022.2101150
摘要

Compositional changes of successively emplaced magmatites can be used to infer changes in their petrogenetic evolution and geodynamic setting. The central-northern Lhasa terrane hosts extensive Late Cretaceous magmatism, however, the mechanism that triggered the magmatism and its relationship to the directly preceding Late Cretaceous tectonic transition in the central Tibetan Plateau is still unresolved. Therefore, we conducted a detailed petrological, geochronological, geochemical, and isotopic study on recently identified Late Cretaceous doleritic and granodioritic rocks in the Xiongmei area, northern Lhasa subterrane. The potassic (K2O/Na2O ratios >1) dolerites (ca. 80 Ma) display a post-collisional basaltic shoshonitic signature with uniform moderately enriched whole-rock Sr–Nd and zircon–Hf isotopic compositions ((87Sr/86Sr)t = 0.7070 to 0.7095, whole-rock εNd(t) = – 2.4 to – 1.3, and zircon εHf(t) = – 5.9 to +1.9), suggesting that they evolved from a similar parental magma and were likely derived by partial melting of an enriched lithospheric mantle metasomatized by hydrous fluids. The granodiorites are geochemically divided into medium-K and high-K calc-alkaline rocks. The medium-K samples (ca. 80 Ma) are generally characterized by low K2O/Na2O ratios <1, whereas the high-K samples (78–76 Ma) display high K2O/Na2O ratios >1. The medium-K samples have positive zircon εHf(t) values from +4.8 to +6.5 and uniform whole-rock ɛNd(t) values from – 2.4 to – 1.3, which significantly differ from those of the high-K samples that have negative to positive zircon εHf(t) values from – 1.9 to +2.8 and negative whole-rock ɛNd(t) values from – 8.4 to – 5.1. The medium-K samples are characterized by high Sr contents and Sr/Y ratios, coupled with low Y and HREE contents, similar to adakitic compositions, and were interpreted to have been derived from deep partial melting of the foundering juvenile garnet-bearing mafic lower crust at relatively low temperatures. Compared to the medium-K samples, the high-K samples have lower Sr/Y and (La/Yb)N ratios, coupled with flat HREE patterns and distinct negative Eu, Sr and Ti anomalies and are most likely derived from shallower partial melting of the K-rich juvenile lower crust at relatively high temperatures. Considering the occurrence of variable magmatism in the central-northern Lhasa subterrane during the Late Cretaceous, the change in magma composition and lower crustal melting conditions (cold-deep vs. hot-shallow) suggest that the lithospheric mantle keel was partially detached by small-scale mantle convection in response to the low-angle Neo-Tethys-associated subduction between 85 and 70 Ma.
最长约 10秒,即可获得该文献文件

科研通智能强力驱动
Strongly Powered by AbleSci AI
更新
大幅提高文件上传限制,最高150M (2024-4-1)

科研通是完全免费的文献互助平台,具备全网最快的应助速度,最高的求助完成率。 对每一个文献求助,科研通都将尽心尽力,给求助人一个满意的交代。
实时播报
松柏完成签到 ,获得积分10
刚刚
ys118完成签到 ,获得积分10
2秒前
轩辕中蓝完成签到 ,获得积分10
3秒前
杂菜流完成签到,获得积分10
7秒前
cata完成签到,获得积分10
8秒前
heija完成签到,获得积分10
8秒前
乌云乌云快走开完成签到,获得积分10
10秒前
小九完成签到,获得积分10
10秒前
芒果布丁完成签到 ,获得积分10
10秒前
wwyy完成签到 ,获得积分10
12秒前
vassallo完成签到 ,获得积分10
17秒前
netyouxiang完成签到,获得积分10
18秒前
SAINT完成签到 ,获得积分10
21秒前
zx完成签到 ,获得积分10
21秒前
一页书完成签到,获得积分10
23秒前
CR完成签到 ,获得积分10
23秒前
挖挖机完成签到 ,获得积分10
24秒前
hyjcs完成签到,获得积分10
26秒前
故意的怜晴完成签到 ,获得积分10
27秒前
爱学习的悦悦子完成签到 ,获得积分10
29秒前
zhao完成签到,获得积分10
30秒前
66完成签到 ,获得积分10
36秒前
彭于晏应助rarfen采纳,获得30
40秒前
潇湘夜雨完成签到,获得积分10
41秒前
浮生若梦完成签到 ,获得积分10
41秒前
优雅的凝阳完成签到 ,获得积分10
42秒前
材1完成签到 ,获得积分10
44秒前
求助完成签到,获得积分0
46秒前
线性谐振子完成签到,获得积分10
46秒前
葛怀锐完成签到 ,获得积分10
48秒前
勤奋谷秋完成签到 ,获得积分10
49秒前
李凤凤完成签到 ,获得积分10
52秒前
飘逸翠柏完成签到 ,获得积分10
53秒前
iNk应助线性谐振子采纳,获得20
53秒前
53秒前
爱听歌的寒香完成签到,获得积分10
58秒前
rarfen发布了新的文献求助30
1分钟前
jeronimo完成签到,获得积分10
1分钟前
乐乐乐乐乐乐应助Beyond095采纳,获得10
1分钟前
natsu401完成签到 ,获得积分10
1分钟前
高分求助中
Licensing Deals in Pharmaceuticals 2019-2024 3000
Cognitive Paradigms in Knowledge Organisation 2000
Effect of reactor temperature on FCC yield 2000
How Maoism Was Made: Reconstructing China, 1949-1965 800
Medical technology industry in China 600
Introduction to Spectroscopic Ellipsometry of Thin Film Materials Instrumentation, Data Analysis, and Applications 600
Shining Light on the Dark Side of Personality 400
热门求助领域 (近24小时)
化学 医学 生物 材料科学 工程类 有机化学 生物化学 物理 内科学 纳米技术 计算机科学 化学工程 复合材料 基因 遗传学 催化作用 物理化学 免疫学 量子力学 细胞生物学
热门帖子
关注 科研通微信公众号,转发送积分 3311314
求助须知:如何正确求助?哪些是违规求助? 2944006
关于积分的说明 8516896
捐赠科研通 2619458
什么是DOI,文献DOI怎么找? 1432306
科研通“疑难数据库(出版商)”最低求助积分说明 664597
邀请新用户注册赠送积分活动 649856