Early Triassic mid-ocean-ridge basalt (MORB)-like diabase swarms in the southeastern segment of the Central Asian Orogenic Belt: A response to lithospheric extension triggered by Paleo-Asian oceanic slab break-off

地质学 地球化学 锆石 玄武岩 镁铁质 俯冲 岩石圈 克拉通 部分熔融 地质年代学 古生物学 构造学
作者
Jing Wang,Wen‐Chun Ge,Wei Wang,Jing Wang,Yu Dong,Zheng Ji,Jun-Hui Bi,Hongying Zhou,De-He Xing
出处
期刊:Geological Society of America Bulletin [Geological Society of America]
标识
DOI:10.1130/b37867.1
摘要

Mafic dike swarms in paleo-subduction zones generally serve as important indicators of tectono-magmatic processes and provide a different perspective on mantle source and geodynamic evolution. The geodynamic evolution of the southeastern segment of the Central Asian Orogenic Belt (CAOB) during the Late Permian−Early Triassic remains unclear, including oceanic ridge subduction, slab break-off, slab roll-back, and post-collision extension. To address these disputes, we carried out a comprehensive study of petrography, whole-rock major and trace elements, mineralogy, secondary ion mass spectrometry (SIMS) zircon U-Pb dating, and in situ zircon Hf isotope and apatite Sr isotope analyses for the newly discovered early Mesozoic diabase swarms in the southern CAOB. High-precision SIMS zircon U-Pb dating of these diabases yielded concordant ages ranging from 250.8 ± 3.8 Ma to 248.2 ± 2.4 Ma, representing the Early Triassic magmatic activities. These diabase samples belong to sub-alkaline series with low SiO2 and K2O contents and relatively high TiO2, MgO, and transition metal element contents (e.g., Cr, Ni). They are enriched in large-ion lithophile elements and depleted in high field strength elements, with Nb-Ta negative anomalies, indicating typical arc-style geochemical affinities. They show weakly fractionated rare earth elements (REE) with flat chondrite-normalized REE patterns similar to enriched mid-ocean-ridge basalt (MORB) and relatively homogeneous and highly depleted isotopic compositions, with zircon εHf(t) values of +2.63 to +7.97 and significantly low apatite 87Sr/86Sr values of 0.703656−0.704147. These diabase samples were originated by ∼5%−10% decompression melting of a mantle wedge (spinel-garnet lherzolite) metasomatized by subduction-related melts, with minor contributions of mid-ocean-ridge basalt (MORB)-like asthenospheric materials. These Early Triassic diabase swarms, together with coeval magmatic flare-ups of high-Mg andesites and Nb-enriched mafic rocks and adakites, confirm a lithosphere extension-related “hot” environment accompanied by the melting of oceanic slab and the associated melt-mantle wedge interactions in the southeastern segment of the CAOB. It is suggested that the Early Triassic diabase swarms were formed in a slab window, triggered by slab break-off of the Paleo-Asian oceanic slab. The upwelling of asthenospheric materials induced decompression melting of the lithospheric mantle, which was favorable for the emplacement of the Early Triassic diabase swarms.
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
PDF的下载单位、IP信息已删除 (2025-6-4)

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
香蕉觅云应助儒雅南风采纳,获得10
1秒前
郭小宝发布了新的文献求助10
5秒前
情怀应助幸福大白采纳,获得10
5秒前
齐天大圣应助幸福大白采纳,获得30
6秒前
孙燕应助幸福大白采纳,获得30
6秒前
英姑应助幸福大白采纳,获得30
6秒前
6秒前
Hashub完成签到,获得积分20
6秒前
8秒前
xueyu发布了新的文献求助10
10秒前
wonder123发布了新的文献求助10
11秒前
科研通AI2S应助张雯思采纳,获得10
12秒前
12秒前
小二郎应助张雯思采纳,获得10
12秒前
情怀应助张雯思采纳,获得10
12秒前
12秒前
科研通AI2S应助张雯思采纳,获得10
12秒前
今后应助张雯思采纳,获得10
12秒前
在水一方应助张雯思采纳,获得10
12秒前
Jasper应助张雯思采纳,获得10
12秒前
41应助张雯思采纳,获得10
12秒前
12秒前
新xin完成签到,获得积分10
13秒前
儒雅南风发布了新的文献求助10
13秒前
xxddw发布了新的文献求助10
13秒前
33发布了新的文献求助30
13秒前
14秒前
14秒前
Rondab应助科研小白采纳,获得10
15秒前
16秒前
wonder123完成签到,获得积分10
16秒前
量子星尘发布了新的文献求助10
18秒前
幸福的乾发布了新的文献求助10
18秒前
xyj6486发布了新的文献求助10
18秒前
19秒前
小晓发布了新的文献求助10
21秒前
Owen应助伏坎采纳,获得10
24秒前
健壮雨兰完成签到,获得积分10
24秒前
LWQ完成签到,获得积分10
25秒前
wanci应助无名采纳,获得10
25秒前
高分求助中
A new approach to the extrapolation of accelerated life test data 1000
ACSM’s Guidelines for Exercise Testing and Prescription, 12th edition 500
‘Unruly’ Children: Historical Fieldnotes and Learning Morality in a Taiwan Village (New Departures in Anthropology) 400
Indomethacinのヒトにおける経皮吸収 400
Phylogenetic study of the order Polydesmida (Myriapoda: Diplopoda) 370
基于可调谐半导体激光吸收光谱技术泄漏气体检测系统的研究 350
Robot-supported joining of reinforcement textiles with one-sided sewing heads 320
热门求助领域 (近24小时)
化学 材料科学 医学 生物 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 遗传学 基因 物理化学 催化作用 冶金 细胞生物学 免疫学
热门帖子
关注 科研通微信公众号,转发送积分 3989444
求助须知:如何正确求助?哪些是违规求助? 3531531
关于积分的说明 11254250
捐赠科研通 3270191
什么是DOI,文献DOI怎么找? 1804901
邀请新用户注册赠送积分活动 882105
科研通“疑难数据库(出版商)”最低求助积分说明 809174