Dynamics of phase fronts in ore-forming fluid systems of volcanic arcs

Abstract

A mathematical model is proposed to describe the dynamics of phase fronts in volcanogenic orthomagmatic fluid systems (VOFS). It has been shown that these systems require rather short geologic times to reach a quasi-stationary state. This process is accompanied by slow cooling and pressure decrease as the bubbling front within the intrusive body submerges and magmatic fluid discharge decreases. Decompression boiling zone seems to develop in near-surface VOFS part for a certain combination of such parameters as porosity, permeability, and upper boundary condition. In evolving VOFS the existence of this zone is ephemeral. However in areas of seismic tremor and in mixed hydrothermal systems this zone can be stable and can produce brines below the level of hydrotherm discharge.

Morphotectonic and petrological characteristics of Permo-Triassic traps of Siberia

“…The top of the Cenozoic-Mesozoic deposits reflects the relief of subvolcanic Permo-Triassic volcanism [48]. The morphology and dimensions of magma formations (Figure 3) are consistent with the dimensions of both shield and stratovolcanoes of intraplate volcanic chains [12,80]. It should be taken into account that at the initial stage of trap volcanism the thickness of the Ivakinskaya suite, which formed igneous rocks in eastern Taimyr, was significantly higher than that of the Kharaelakh synclinal folds [29].…”

“…For intraplate geodynamic processes with the formation of faults in lithospheric rocks, the sources of such deformations can be global and local stretching of the lithosphere affected by convective flows in the upper mantle, both with and without the formation of decompression melting regions [10][11]. By numerical modelling of the rift formation above asthenosphere zones for areas of slow-spreading ridges [12] and the evolution of upper mantle plumes under the WSP and SC lithosphere [13][14][15], we calculated lateral dimensions of rift valleys over ascending convective flows above hot spots as the first tens of kilometres by model [5]. The manifestation of mantle thermochemical plumes in the presence of a phase boundary between mantle reservoirs [16] in the studied model of hot spots coincided with the sizes of asthenosphere zones.…”

“…Data of petrochemical compositions in traps from different parts of the West Siberian Plate and the Siberian Craton: (1) SG-6, (2) NKC-1, (3) VK-42.43 -numbers of reference sections in the deep and super-deep wells of the same name [32-33]; (4) Kuzbass [90-91]; (5) Taimyr [92-93]; (6) Mid-North SibLIP -data of Almukhamedov and Medvedev, estimates of Tb/Yb in works [94-95]; (7) Meymecha-Kotui -[96] (for the Onkuchanskaya suite of the Maymecha-Kotui province); (8) Lama lake -authors' data for the volcanic section of its south margin; (9) Dyupkun lake -data for volcanic section of its margins[29];(10) West SibLIP[92][93];(11) South SibLIP data by S.D. Kurtseraite,(12) Kamensky Dyke belt (North) -data by[29].…”

The Dynamic Structural-Material Complexes of the Earth’s Crust

“…The time required for the formation of a deposit of a particular ore formation is also different. According to estimates (depending on the parameters and genesis), for plutonogenic, hydrothermal, and stratiform deposits, it is no more than 10 5 -10 6 years [122,148]; in the case of polygenicity and polychrony, it is much longer [127,128]. The duration of the formation of sedimentary formations is also different.…”

The Dynamic Structural-Material Complexes of the Earth’s Crust

“…For the formation of a deposit of a particular ore-formation the time is also different required. For plutonogenic, hydrothermal, and stratiform deposits, it is no more than 10 5 -10 6 years [148,122 ]; in the case of polygenicity and polychromy, it is much longer [127,128], according to estimates (depending on the parameters and genesis). The deposit of sedimentary formations the duration is also different.…”