Minimum critical thickness of dike for ore-bearing fluid injection: A new approach applied to the Shihu gold deposit, Hebei Province, North China

The Huajian gold deposit is located in the metallogenic belt of the northern part of the North China block. This deposit's ore bodies are mainly hosted in metamorphosed Neoarchean and Mesoproterozoic sedimentary rocks, of which Mesozoic volcano-intrusive complexes are closely associated with the Gold mineralization. The FIs of the Huajian deposit are primarily aqueous FIs with minor gas FIs. The pure gas or liquid FIs are very few. The ore-forming fluids were characterised by moderate–low temperature, low salinity and high oxygen fugacity and belonged to an H2O–NaCl ± CO2system. The FIs in quartz veins primarily developed in temperature intervals of 202–380°C, 191–407°C and 170–307°C., corresponding to salinities of 3.85wt.% to 11.23 wt.%, 3.69wt.% to 10.99 wt.% and 2.06wt.% to 17 wt.% NaCl eq.., respectively. The trapping pressures of the FIs from high temperature fluids in the quartz veins are 10-90 MPa, corresponding to depths of 1.0–10 km, assuming a density of the overlying rocks of 0.54 g/cm3–0.98 g/cm3. Multiple stages of phase separation or immiscibility of ore-forming fluid was critical for the formation of the Huajian deposit.

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Laser probe 40Ar/39Ar dating for quartz from auriferous quartz veins in the Shihu gold deposit, western Hebei Province, North China

Chinese Journal of Geochemistry ◽

10.1007/s11631-010-0477-z ◽

2010 ◽

Vol 29 (4) ◽

pp. 438-445 ◽

Cited By ~ 9

Author(s):

Ye Cao ◽

Shengrong Li ◽

Huafeng Zhang ◽

Chong Ao ◽

Zhenzhen Li ◽

...

Keyword(s):

Gold Deposit ◽

North China ◽

Hebei Province ◽

Laser Probe ◽

Quartz Veins

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A new approach to the hydraulic fracture geometric dimensions determination

Proceedings of the Mavlyutov Institute of Mechanics ◽

10.21662/uim2017.1.018 ◽

2017 ◽

Vol 12 (1) ◽

pp. 126-134

Author(s):

A.M. Ilyasov

Keyword(s):

Exact Solution ◽

Hydraulic Fracture ◽

Pressure Gauge ◽

Hyperbolic Type ◽

Fluid Injection ◽

Fracturing Fluid ◽

New Approach ◽

Gauge Data ◽

Bottomhole Pressure ◽

Half Length

Based on the generalized Perkins-Kern-Nordgren model (PKN) for the development of a hyperbolic type vertical hydraulic fracture, an exact solution is obtained for the hydraulic fracture self-oscillations after terminating the fracturing fluid injection. These oscillations are excited by a rarefaction wave that occurs after the injection is stopped. The obtained solution was used to estimate the height, width and half-length of the hydraulic fracture at the time of stopping the hydraulic fracturing fluid injection based on the bottomhole pressure gauge data.

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A Giant Ostrich from the Lower Pleistocene Nihewan Formation of North China, with a Review of the Fossil Ostriches of China

Diversity ◽

10.3390/d13020047 ◽

2021 ◽

Vol 13 (2) ◽

pp. 47

Author(s):

Eric Buffetaut ◽

Delphine Angst

Keyword(s):

Geographical Distribution ◽

Late Pleistocene ◽

North China ◽

Hebei Province ◽

Early Pleistocene ◽

Wide Geographical Distribution ◽

Lower Pleistocene ◽

The Crimea

A large incomplete ostrich femur from the Lower Pleistocene of North China, kept at the Muséum National d’Histoire Naturelle (Paris), is described. It was found by Father Emile Licent in 1925 in the Nihewan Formation (dated at about 1.8 Ma) of Hebei Province. On the basis of the minimum circumference of the shaft, a mass of 300 kg, twice that of a modern ostrich, was obtained. The bone is remarkably robust, more so than the femur of the more recent, Late Pleistocene, Struthio anderssoni from China, and resembles in that regard Pachystruthio Kretzoi, 1954, a genus known from the Lower Pleistocene of Hungary, Georgia and the Crimea, to which the Nihewan specimen is referred, as Pachystruthio indet. This find testifies to the wide geographical distribution of very massive ostriches in the Early Pleistocene of Eurasia. The giant ostrich from Nihewan was contemporaneous with the early hominins who inhabited that region in the Early Pleistocene.

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