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博友高敏老师给我留言,问“科伯构造”是什么,我不知道,第一次回答时还以为问的是天文学中的“Kuiper Belt”呢。高老师回信说是构造地质学用语,遗憾的是我确实没记住有这样一个词汇。
为了弄清这个词汇,我反复在互联网上查询,终于找到有限的几篇文献:
Smoot, N.Christian; Choi, Dong R.; Meyerhoff, Arthur Augustus; Bhat, Mohammad I.; Morris, A. E.L.; Agocs, W. B.; Kamen-Kaye, M.; Taner, I. (1996). Surgetectonics: a new hypothesis of global geodynamics. Solid-State Science andTechnology Library.
Springer Netherlands. p. 348. ISBN 978-0-7923-4156-7.
我认为,这个词汇是上世纪九十年代《涌流构造》(Surge tectonics)中强调的一种构造,但最终没能在学术界流行。在讨论中国大地构造问题时我自己还是倾向于使用通俗易懂的词汇而避免生冷用语,免得造成误解。
现将部分叙述拷贝到这里,供构造地质学同行讨论====================
Kobergens(“科伯”构造?)
Kobergen—bilaterally deformed foldbelt produced by surgechannel tectogenesis. Tectogenesis generates compression, tension, and shear at the same timewithin the tectonic belt or at different times in any one part of the belt.Folds, thrusts, and nappes lie along the flanks, the flanks being mirror images of each other. Thebelts can be hundreds to thousands of kilometers long. They have been variouslyknown as biliminalfoldbelts, bisymmetrical foldbelts, bivergentfoldbelts, bivergentorogens, bivergent structural fans, divergent thrustbelts, fan structures, wedges, and many others. Kobergens form an evolutionary sequence fromcontinents-ocean margin where part of the lithosphere is relatively thin
tocontinent-interior kobergens where the lithosphere is relatively thick, or alpinotype or germanotypekobergens.
Germnotypekobergens form when the lighosphere is 20--35.km thick.
They include activelyrising mountain chains, plateaus, and intracratonic basins. Alpinotypekobergens form where the lighosphere in thinner at10.km thick. Alpinotypekobergens as a rule are associated with the continent-ocean interfacewhose geomorphic expression is midocean ridges, aseismic submarine ridges, oceanic rises, linear island and seamountchains, eugeosynclines and active volcanic arcs, foldbelts, and long-linear to curvilinearvalleys
such as fracture zones. Essentially, bivergenttectogenesis is a principal identifyingcharacteristic of a deformed surge channel, so kobergens are one of the most importantstructures of the surge tectonic concepts.
Kobergen是涌流通道构造运动产生的双侧变形构造。构造运动在构造带中同时或不同时产生挤压、拉伸和剪切构造。褶皱、逆冲和推覆体沿着构造带的侧翼分布,而构造带的两侧呈现镜像对称。构造带长度从几百到几千千米,可以是双向有限的褶皱带、双侧对称的褶皱带、双边褶皱带、双边造山带、双边构造扇体、双向外冲的逆冲带、扇状构造、楔状构造或其他构造等。Kobergens形成一个演化的序列:从岩石圈相对薄的洋—陆边界到岩石圈相对厚的大陆内部构造,或者从阿尔卑斯型到日耳曼型kobergens。日耳曼型kobergens岩石圈厚度为20—35km,包括正在生生的山链、高原以及克拉通内盆地;阿尔卑斯型kobergens岩石圈更薄,为10km厚,一般与洋—陆边界相关,地形上表现为洋中脊、无地震的海洋水下山脊、洋隆、线状岛链、优地槽和活动火山弧、褶皱带以及长线形或弯曲线状谷地如裂谷带。本质上讲,双边构造是变形涌流通道的主要的鉴别特征,因此kobergens是涌流构造概念中的最重要构造之一。
下面是我制作的PPT文件,供大家参考。
Surge Tectonic Hypothesis.pptx
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