CAJ | 학술논문

浙江诸暨陈蔡地区发育一套副变质岩层，由中深度变质的片麻岩、片岩和大理岩组成，与双溪坞群为断层接触，其地质时代多被视为与江山-绍兴断裂带南东侧的华夏地块古老变质基底相同。陈蔡岩群地处江绍断裂带北东端，变质和变形较深，前人将其划归为华夏古陆的小块体，地层时代曾与福建古元古代麻源岩群或浙江八都岩群和江西中元古代铁砂街组对比。在陈蔡岩群下吴宅组含榴夕线黑云斜长片麻岩及含榴黑云斜长片麻岩中获得大量的锆石，具有典型的核、幔、边结构，核部年龄集中在新元古代，206Pb/238U年龄加权平均值为848±10Ma和845±9Ma，锆石后期增生边部年龄多为加里东期的年龄，206Pb/238U年龄加权平均值为431.4±7.8Ma。陈蔡岩群斜长片麻岩获得的锆石核部较单一的U-Pb年龄，反映出陈蔡岩群下吴宅组夕线石所代表的泥质成分所含的锆石单一，其锆石核部年龄应代表陈蔡岩群下吴宅组的原岩年龄；同时，认为陈蔡岩群既不能与福建古元古代的麻源岩群对比，也不能与江西地区中元古代铁砂街组对比。其原岩为稍晚于双溪坞群（905~877Ma）的新元古代地层（848~845Ma），从年代上倾向于江南造山带范畴。该年龄对江山-绍兴断裂带变质地层的区域对比和构造演化有重要意义。
절강제기진채지구발육일투부변질암층，유중심도변질적편마암、편암화대리암조성，여쌍계오군위단층접촉，기지질시대다피시위여강산-소흥단렬대남동측적화하지괴고로변질기저상동。진채암군지처강소단렬대북동단，변질화변형교심，전인장기화귀위화하고륙적소괴체，지층시대증여복건고원고대마원암군혹절강팔도암군화강서중원고대철사가조대비。재진채암군하오택조함류석선흑운사장편마암급함류흑운사장편마암중획득대량적고석，구유전형적핵、만、변결구，핵부년령집중재신원고대，206Pb/238U년령가권평균치위848±10Ma화845±9Ma，고석후기증생변부년령다위가리동기적년령，206Pb/238U년령가권평균치위431.4±7.8Ma。진채암군사장편마암획득적고석핵부교단일적U-Pb년령，반영출진채암군하오택조석선석소대표적니질성분소함적고석단일，기고석핵부년령응대표진채암군하오택조적원암년령；동시，인위진채암군기불능여복건고원고대적마원암군대비，야불능여강서지구중원고대철사가조대비。기원암위초만우쌍계오군（905~877Ma）적신원고대지층（848~845Ma），종년대상경향우강남조산대범주。해년령대강산-소흥단렬대변질지층적구역대비화구조연화유중요의의。
A series of parametamorphic rocks, as the oldest metamorphosed basement in the Jiangshan-Shaoxing fault zone, consist of gneiss, schist and marble of medium-deep metamorphism and are in fault contact with the Shuangxiwu Group in Chencai area, Zhu-ji County, Zhejiang Province. Because the Chencai Group which suffered deep metamorphism and deformation is developed in the southern part of the Jiangshan-Shaoxing fault zone, most Chinese geologists assign the group to the small patch of the Cathysia Plate and make correlation with Paleoproterozoic Mayuan Group in Fujian Province or the Badu Group in Zhejiang Province and the Me-soproterozoic Tieshajie Foramtion in Jiangxi Province. Lots of zircons were collected from garnet sillimanite biotite plagiogneiss and sillimanite garnet biotite gneiss in the Xiawuzhai Formation of the Chencai Group. The zircons have a typical core, mantle and edge structure, the age of the core is usually in the range of 848~845Ma and the age of the late accretion edge is Caledonian (431Ma). Ac-cording to the zircon dating of the plagioclase gneiss of the Chencai Group, the authors consider that the Chencai Group can not on-ly be correlated with the Paleoproterozoic Mayuan Group of Fujian Province, but also with Mesoproterozoic Tieshajie Formation of Jiangxi Province. The protolith age of the Chencai Group suggests Neoproterozoic ( 848~845Ma), which is younger than that of the Shuangxiwu Group (905~877Ma) in the stratigraphic column and the stratigraphic division, and the age belongs to the domain of the Jiangnan Orogenic Belt. However, this age has an important significance in the correlation of metamorphosed provinces in the Jiang-Shan-ShaoXing fault zone and the study of its tectonic evolution.