1958—1999年,在广东省佛山市南海区西樵镇一带发现了众多记录了史前人类活动的石器地点,石器中包括双肩石器和细石器。迄今为止,“西樵山遗址”被认定是4—7 ka B P的大型新石器时期采石场和加工场。2011—2022年,笔者经多次地质遗迹...1958—1999年,在广东省佛山市南海区西樵镇一带发现了众多记录了史前人类活动的石器地点,石器中包括双肩石器和细石器。迄今为止,“西樵山遗址”被认定是4—7 ka B P的大型新石器时期采石场和加工场。2011—2022年,笔者经多次地质遗迹和地质环境调查,在西樵山东南麓富贤村北面发现了良好的第四纪地层剖面。地质探槽剖面测量和地质年代学研究表明:富贤地点存在2套原始沉积地层:上部为第四纪全新世沼泽相地层,AMS14C校正年龄为5052—5409 a B P;下部为第四纪晚更新世冲积-洪积相地层,AMS14C校正年龄为38420—40502 a B P,OSL (光释光)年龄为41.977—43.796 ka B P;在晚更新世地层中发现2层含旧石器层,下部A1层主要石器类型有较大型刮削器、尖刃器、舌型刃器及小型石片工具,如各类刮削器、锯齿刃器、凹缺器、石刀、使用石片、石核等,包括带铤斧型小石刀;上部A2层明显出现更多石刀类型且常常附带修背和修铤工作,其中一件用于生产细小长石片的原始楔形石核引人关注。据平均沉积速率计算,下部A1石器层年龄为46.511—47.325 ka B P,上部A2石器层年龄为41.977—42.167 ka B P;距今大于5 ka的全新世沉积物中的石制品数量虽少,但器物类型仍具有明显继承性与发展性特点。本文的发现更新并延伸了西樵山国家地质公园和“西樵山文化”的内涵,首次突破了珠江三角洲地区有确切年代的晚更新世旧石器遗存的纪录,追踪到大约40—50 ka现代人在华南沿海的足迹,揭示了同期石器工业的面貌及其文化内涵的发展特征和演变。研究表明,在MIS3间冰段相对湿热时期以及MIS2相对干冷阶段,富贤地点的古人类面临环境变化的挑战而开启了新的生计模式,这对于揭示现代人对全球和区域环境变化的响应与适应的科学问题具有重要意义。展开更多
Metapelite is one of the predominant rock types in the high-pressure–ultrahigh-pressure（HP–UHP） metamorphic belt of western Tianshan, NW China; however, the spatial and temporal variations of this belt during meta...Metapelite is one of the predominant rock types in the high-pressure–ultrahigh-pressure（HP–UHP） metamorphic belt of western Tianshan, NW China; however, the spatial and temporal variations of this belt during metamorphism are poorly understood. In this study, we present comparative petrological studies and 40^Ar/39 ^Ar geochronology of HP and UHP pelitic schist exposed along the Habutengsu valley. The schist mainly comprises quartz, white mica, garnet, albite and bluish amphibole. In the Mn O–Na2O–Ca O–K2O–Fe O–Mg O–Al2O3–Si O2–H2O（Mn NCKFMASH） system, P–T pseudosections were constructed using THERMOCALC 333 for two representative pelitic schists. The results demonstrate that there was a break in the peak metamorphic pressures in the Habutengsu area. The northern schist has experienced UHP metamorphism, consistent with the presence of coesite in the same section, while the southern one formed at lower pressures that stabilized the quartz. This result supports the previous finding of a metamorphic gradient through the HP–UHP metamorphic belt of the Chinese western Tianshan by the authors. Additionally, phengite in the northern schist was modelled as having a Si content of 3.55–3.70（a.p.f.u.） at the peak stage, a value much higher than that of oriented matrix phengite（Si content 3.32–3.38 a.p.f.u.）. This indicates that the phengite flakes in the UHP schist were subjected to recrystallization during exhumation, which is consistent with the presence of phengite aggregates surrounding garnet porphyroblast. The 40^Ar/39^ Ar age spectra of white mica（dominantly phengite） from the two schists exhibit similar plateau ages of ca. 315 Ma, which is interpreted as the timing of a tectonometamorphic event that occurred during the exhumation of the HP–UHP metamorphic belt of the Chinese western Tianshan.展开更多
The microstructure and solute distribution of Pd40Ni40P40 alloy solidified both on board a Chinese retrievable satellite (μg) and on the earth (1g) were studied. It was found that the dendritic primary phase formed u...The microstructure and solute distribution of Pd40Ni40P40 alloy solidified both on board a Chinese retrievable satellite (μg) and on the earth (1g) were studied. It was found that the dendritic primary phase formed under microgravity condition was finer and shorter. In the central area of the sample some asteroidal patterns of the primary phase were present in the microstructure. The primary spacing of the dendrites at the cooling rate of 0.056 K/s was smaller than that measured in the ground-based experiments at the same cooling rate, but almost the same as that cooled at 0.67 K/s on the ground. With these experimental results, mass transport coefficients both in space and on the earth were evaluated.展开更多
文摘1958—1999年,在广东省佛山市南海区西樵镇一带发现了众多记录了史前人类活动的石器地点,石器中包括双肩石器和细石器。迄今为止,“西樵山遗址”被认定是4—7 ka B P的大型新石器时期采石场和加工场。2011—2022年,笔者经多次地质遗迹和地质环境调查,在西樵山东南麓富贤村北面发现了良好的第四纪地层剖面。地质探槽剖面测量和地质年代学研究表明:富贤地点存在2套原始沉积地层:上部为第四纪全新世沼泽相地层,AMS14C校正年龄为5052—5409 a B P;下部为第四纪晚更新世冲积-洪积相地层,AMS14C校正年龄为38420—40502 a B P,OSL (光释光)年龄为41.977—43.796 ka B P;在晚更新世地层中发现2层含旧石器层,下部A1层主要石器类型有较大型刮削器、尖刃器、舌型刃器及小型石片工具,如各类刮削器、锯齿刃器、凹缺器、石刀、使用石片、石核等,包括带铤斧型小石刀;上部A2层明显出现更多石刀类型且常常附带修背和修铤工作,其中一件用于生产细小长石片的原始楔形石核引人关注。据平均沉积速率计算,下部A1石器层年龄为46.511—47.325 ka B P,上部A2石器层年龄为41.977—42.167 ka B P;距今大于5 ka的全新世沉积物中的石制品数量虽少,但器物类型仍具有明显继承性与发展性特点。本文的发现更新并延伸了西樵山国家地质公园和“西樵山文化”的内涵,首次突破了珠江三角洲地区有确切年代的晚更新世旧石器遗存的纪录,追踪到大约40—50 ka现代人在华南沿海的足迹,揭示了同期石器工业的面貌及其文化内涵的发展特征和演变。研究表明,在MIS3间冰段相对湿热时期以及MIS2相对干冷阶段,富贤地点的古人类面临环境变化的挑战而开启了新的生计模式,这对于揭示现代人对全球和区域环境变化的响应与适应的科学问题具有重要意义。
基金financially supported by National Natural Science Foundation of China(Nos 41372004,41330210,41121062)
文摘Metapelite is one of the predominant rock types in the high-pressure–ultrahigh-pressure（HP–UHP） metamorphic belt of western Tianshan, NW China; however, the spatial and temporal variations of this belt during metamorphism are poorly understood. In this study, we present comparative petrological studies and 40^Ar/39 ^Ar geochronology of HP and UHP pelitic schist exposed along the Habutengsu valley. The schist mainly comprises quartz, white mica, garnet, albite and bluish amphibole. In the Mn O–Na2O–Ca O–K2O–Fe O–Mg O–Al2O3–Si O2–H2O（Mn NCKFMASH） system, P–T pseudosections were constructed using THERMOCALC 333 for two representative pelitic schists. The results demonstrate that there was a break in the peak metamorphic pressures in the Habutengsu area. The northern schist has experienced UHP metamorphism, consistent with the presence of coesite in the same section, while the southern one formed at lower pressures that stabilized the quartz. This result supports the previous finding of a metamorphic gradient through the HP–UHP metamorphic belt of the Chinese western Tianshan by the authors. Additionally, phengite in the northern schist was modelled as having a Si content of 3.55–3.70（a.p.f.u.） at the peak stage, a value much higher than that of oriented matrix phengite（Si content 3.32–3.38 a.p.f.u.）. This indicates that the phengite flakes in the UHP schist were subjected to recrystallization during exhumation, which is consistent with the presence of phengite aggregates surrounding garnet porphyroblast. The 40^Ar/39^ Ar age spectra of white mica（dominantly phengite） from the two schists exhibit similar plateau ages of ca. 315 Ma, which is interpreted as the timing of a tectonometamorphic event that occurred during the exhumation of the HP–UHP metamorphic belt of the Chinese western Tianshan.
文摘The microstructure and solute distribution of Pd40Ni40P40 alloy solidified both on board a Chinese retrievable satellite (μg) and on the earth (1g) were studied. It was found that the dendritic primary phase formed under microgravity condition was finer and shorter. In the central area of the sample some asteroidal patterns of the primary phase were present in the microstructure. The primary spacing of the dendrites at the cooling rate of 0.056 K/s was smaller than that measured in the ground-based experiments at the same cooling rate, but almost the same as that cooled at 0.67 K/s on the ground. With these experimental results, mass transport coefficients both in space and on the earth were evaluated.
