贵州三叠纪化石群古地理和古生态全球对比分析与世界遗产价值

在世界范围内,"贵州三叠纪化石群"是为数不多的三叠纪化石群产地之一。该生物群是海生爬行动物类、海百合类、脊椎动物类、无脊椎动物类、鱼类、植物类等为一体的生物群,世界罕见。为探究该化石群具有的潜在遗产价值,以对比的思想为指导,从化石群的古地理与古生态环境等几个方面为切入点,采用对比分析的方法,与世界范围内有关三叠纪生物群的世界遗产地或重要的、具有可比性的三叠纪生物群进行对比,探究其潜在的世界遗产价值和全球唯一性。结果表明:该地区在古地理上位于特提斯洋的东段,属于西特提斯古地理构架与东太平洋古地理构架的过渡地区,具有特殊性。同时,记录了三叠纪安尼期—卡尼期的连续完整的地质演化史与生物演化过程,代表着中生代古生物演化的重要阶段,在世界自然遗产提名中具有突出普遍价值。

化石类世界遗产的基本特征及贵州三叠纪化石群申遗策略

化石类世界自然遗产作为地球演化历史中动植物生命记录的突出例证,其自身及赋存环境对重新建构古地理、古气候、古生态等信息具有重要意义。了解化石类世界自然遗产的基本特征,有利于为全球范围内潜在化石遗址申报世界自然遗产提供借鉴及更好地开展已有化石类世界自然遗产的保护管理工作。文章从全球分布特征、关键生物事件对全球范围内化石类世界自然遗产的基本特征进行研究,分析了贵州三叠纪化石群潜在的世界遗产价值,并提出贵州省三叠纪化石群的申遗策略:按照系列遗产申报的模式进行申报、按照世界自然遗产属性选择第八条评价标准申报,加强提名地的保护与管理。

古生物化石旅游纪念品设计研究——以贵州三叠纪化石群为例

贵州三叠纪化石群物种多样性丰富、化石分布广泛、保存完美,其旅游纪念品设计开发有广阔的市场和巨大的提升空间。本文以贵州三叠纪化石群为例,研究古生物化石旅游纪念品的设计方式。在分析贵州三叠纪化石群旅游纪念品设计现状的基础上,提出单一原型化、多元融合化的设计理念,实现贵州三叠纪化石群旅游纪念品实用性、艺术性、纪念性、科学性的统一,初步设计了10余款化石旅游纪念品。将古生物化石与少数民族工艺相结合,既能够满足游客对旅游纪念品的需求又能够促进少数民族群众增收致富,也能够更好的保护化石这一不可再生资源,促进贵州三叠纪化石群的保护性利用。

Carbonate metasomatism in the lithospheric mantle: Implications for cratonic destruction in North China

The activity of melts and fluids may have played a key role in inducing the destruction of the eastern North China Craton in the early Cretaceous. Carbonate melts are important agents in mantle metasomatism and can significantly modify the physical and chemical properties of the subcontinental lithospheric mantle. Carbonate metasomatism can be identified by specific geochemical indices in clinopyroxene, such as high Ca/Al and low Ti/Eu ratios. This study presents the spatial and temporal variations of carbonate metasomatism in the lithospheric mantle beneath the eastern North China Craton. Three types of carbonate metasomatism are classified based on the geochemical compositions of clinopyroxene in mantle peridotites. Clinopyroxene formed by Type 1 carbonate metasomatism is characterized by very high Ca/Al ratios(15–70) and^(87)Sr/^(86)Sr ratios(0.706–0.713). Clinopyroxene derived from Type 2 carbonate metasomatism shows relatively high Ca/Al ratios(5–18) and^(87)Sr/^(86)Sr ratios(0.703–0.706). However, clinopyroxene resulting from Type 3 carbonate metasomatism has low Ca/Al ratios(5–9) and^(87)Sr/^(86)Sr ratios(0.702–0.704). Deep(garnet-bearing) and shallow(spinel-bearing) lithospheric mantle beneath the Sulu orogen and surrounding areas in the eastern North China Craton were affected by intense Type 1 carbonate metasomatism before the late Triassic. The deep subduction of the South China Block with its accompanying carbonate sediments was the trigger for Type 1 carbonate metasomatism, which reduced strength of the lithospheric mantle and provided a prerequisite for the destruction of the eastern North China Craton in the early Cretaceous. After the destruction of the eastern North China Craton, the ancient relict lithospheric mantle, represented by spinel harzburgite xenoliths hosted in the late Cretaceous to Cenozoic basalts,only recorded Type 2 carbonate metasomatism. This implies that the lithospheric mantle experienced the intense Type 1 carbonate metasomatism was completely destroyed and not preserved during decratonization. Spinel lherzolite xenoliths hosted in the late Cretaceous to Cenozoic basalts represent the young, fertile lithospheric mantle formed after the cratonic destruction and only a few samples record Type 2 and 3 carbonate metasomatisms. We suggest that carbonate melts derived from the subduction-modified asthenospheric mantle with variable proportions of recycled crustal material was responsible for the Type 2 and 3 carbonate metasomatisms. The carbonate metasomatism of the lithospheric mantle beneath the Jiaodong Peninsula and surrounding areas is very pervasive and is spatially consistent with the remarkable thinning of lithospheric mantle and giant gold deposits in this region. Therefore, we conclude that carbonate metasomatism in the lithospheric mantle played a crucial part in the modification, destruction and gold deposits in the eastern North China Craton.