CAJ | 학술논문

在中国大陆的许多地区都已发现大于3.4Ga的锆石和岩石.鞍山是全球仅有几个存在≥3.8Ga岩石的地区之一.它们以不大的规模存在于白家坟、东山、深沟寺杂岩中,由糜棱岩化奥长花岗岩、条带状奥长花岗岩和变质石英闪长岩组成.近年来,在鞍山地区还发现了许多3.7～3.6Ga岩石和锆石.锆石Hf同位素组成表明鞍山地区在3.8～3.6Ga期间存在周期性的地幔添加和陆壳形成.除鞍山外,在中国许多地区的不同类型岩石中也获得了≥3.4Ga锆石,虽然它们大多数都是碎屑和残余成因.(1)华北克拉通冀东铬云母石英岩中3.85～3.55Ga碎屑锆石:(2)华北克拉通信阳中生代火山岩长英质麻粒岩中3.66Ga岩浆锆石;(3)华南克拉通宜昌地区杨子地块新元古代砂岩中3.80Ga碎屑锆石(一颗);(4)华南克拉通华夏地块新元古代一古生代变质沉积岩中3.76～3.6Ga碎屑锆石;(5)西北地区塔里木地块阿克塔什塔格地区古元古代片麻状花岗岩中3.6Ga残余锆石;(6)西秦岭奥陶纪变质火山岩中4.08Ga捕掳锆石(一颗);(7)西藏普兰地区奥陶纪石英岩中4.1Ga碎屑锆石(一颗,有3.61Ga增生边).一些古老锆石有高达4.1～4.0Ga的Hf同位素模式年龄.在中国,>3.4Ga地壳物质的比例以往被低估了,发现冥古宙和始太古代物质的可能性仍然存在,它们将对中国早期陆壳演化提供新的制约.
재중국대륙적허다지구도이발현대우3.4Ga적고석화암석.안산시전구부유궤개존재≥3.8Ga암석적지구지일.타문이불대적규모존재우백가분、동산、심구사잡암중,유미릉암화오장화강암、조대상오장화강암화변질석영섬장암조성.근년래,재안산지구환발현료허다3.7～3.6Ga암석화고석.고석Hf동위소조성표명안산지구재3.8～3.6Ga기간존재주기성적지만첨가화륙각형성.제안산외,재중국허다지구적불동류형암석중야획득료≥3.4Ga고석,수연타문대다수도시쇄설화잔여성인.(1)화북극랍통기동락운모석영암중3.85～3.55Ga쇄설고석:(2)화북극랍통신양중생대화산암장영질마립암중3.66Ga암장고석;(3)화남극랍통의창지구양자지괴신원고대사암중3.80Ga쇄설고석(일과);(4)화남극랍통화하지괴신원고대일고생대변질침적암중3.76～3.6Ga쇄설고석;(5)서북지구탑리목지괴아극탑십탑격지구고원고대편마상화강암중3.6Ga잔여고석;(6)서진령오도기변질화산암중4.08Ga포로고석(일과);(7)서장보란지구오도기석영암중4.1Ga쇄설고석(일과,유3.61Ga증생변).일사고로고석유고체4.1～4.0Ga적Hf동위소모식년령.재중국,>3.4Ga지각물질적비례이왕피저고료,발현명고주화시태고대물질적가능성잉연존재,타문장대중국조기륙각연화제공신적제약.
Zircons and rocks older than 3.4Ga have been discovered in many areas of Chinese continent. Anshan City is one of a few areas in the world where≥3.8Ga continental rocks have been identified. They occur in volumetrically small amounts in the Baijiafen, Dongshan and Shengousi complexes and consist of mylonitized trondhjemite, banded trondhjemite and meta-quartz diorite. Many 3.7～3.6Ga rocks and zircons have also been found recently in the Anshan area. The Hf isotopes of the zircons indicate that Anshan mantle addition and continental formation happened episodically from 3.8 to 3.6Ga. Besides Anshan, ≥3.4Ga ages of zircons from different kinds of rocks in many areas of China have also been obtained, although most of them are detrital and inherited in origin. (1) 3.85～3.55Ga detrital zircons from Arehaean fuehsite quartzite in eastern Hebei, North China Craton (NCC); (2) 3.66Ga magmatic zircons from felsic granulite xenoliths in Mesozoic voleanic rocks in Xinyang, NCC; (3) 3.80Ga detrital zircon (one grain) from Neoproterozoic sandstone in Yichang of the Yangtze Block, South China Craton (SCC); (4) 3.76～3.6Ga detrital zircons from Neoproterozoie-Palaeozoic meta-sedimentary rocks in the Cathaysia Block, SCC; (5) 3.6Ga inherited zircons from a Palaeoproterozoic gneissic granite in the Aketashtage area, Tarim Block, Northwest of China. (6) A grain of 4.08Ga old zircon captured by an Ordovician meta-volcanic rock in Zhangjiazhuang, West of northern Qinling orogen; (7) One 4. 1 Ga detrital zircon (with 3.61 Ga rim) from an Ordovician quartzite in Pulan, Tibet. Some of the ancient zircons have Hf isotope model ages as old as 4.1～4.0Ga. The proportion of>3.4Ga crustal materials in China has been underestimated and there are new possibilities for finding Hadean and Eoarchean materials to constrain early terrestrial evolution.