According to the drive of planetary-scale upper magma fluid motions associated with the core-magma angular momentum exchange in the early Earth’s interior, this paper reviewed the results of continental drift studied...According to the drive of planetary-scale upper magma fluid motions associated with the core-magma angular momentum exchange in the early Earth’s interior, this paper reviewed the results of continental drift studied over the last three decades. The theoretical speculation is in good fit to the traces of geological events left on the Earth’s surface. A northeastward drift directionality of the Australian, African, and South American continents relative to the Antarctica Continent in the Southern Hemisphere is reanalyzed according to the slowing down of the early Earth’s rotation. Six traces of significant back-and-forth drifts of the Australian and Asian continents left respectively on the Southwest and Northwest Pacific seafloors are reidentified according to the gradually decreasing amplitude of core-magma angular momentum exchange during early geological evolution. Finally, the thickening and shortening of different continents during the early drift processes are re-simulated by using a simple magma fluid dynamical model.展开更多
Intrinsic magmatic processes are considered as critical operators of plate movements. Here we demonstrate the role of extrinsic processes consequent to intrinsic processes as a catalyst for anomalous rapid plate movem...Intrinsic magmatic processes are considered as critical operators of plate movements. Here we demonstrate the role of extrinsic processes consequent to intrinsic processes as a catalyst for anomalous rapid plate movement. The rapid and accelerated flight of the Indian subcontinent since Deccan volca- nism until its collision with Eurasia remains as one of the geological conundrums. Data on seismic to- mography, peninsular geomorphology and inferences on continuum of subcrustal structures are utilized to address this enigma. We propose geomorphic isostasy as the mechanism that has driven this fastest drift ever recorded in geological history. It was initiated by sudden instability after the Deccan volcanism and resultant extensive accumulation of lava pile over continental lithosphere of northern India, northern-eastern tilt due to crustal thickness heterogeneity and subcrustal thermal stratification. The drift was sustained by Carlsberg and Central Indian ridge-push until collision and sediment top loading at northeast thenceforth. These inferences and geomorphic isostasy as a catalytic mechanism necessitate variability of drift rates as integral inputs for any continental scale modeling.展开更多
Sandstones sampled from Patti Formation,Southern Bida Basin,were studied geochemically using Inductively Coupled Plasma Atomic Emission Spectrophotometer(ICP-AES)and an Inductively Coupled Plasma Mass Spectrometry(ICP...Sandstones sampled from Patti Formation,Southern Bida Basin,were studied geochemically using Inductively Coupled Plasma Atomic Emission Spectrophotometer(ICP-AES)and an Inductively Coupled Plasma Mass Spectrometry(ICP-MS)technique to evaluate their weathering and tectonic setting as well as to deduce the paleo-climatic conditions that existed during their deposition.Geochemically,SiO_(2)range from 73.9%to 86.2%,Al_(2)O_(3)(6.7%~17.1%),Fe_(2)O_(3)(1.1%~1.9%),K_(2)O(0.1%~0.7%)while MgO,CaO,Na_(2)O,P_(2)O_(5),MnO and TiO_(2)were<1%.Enriched in Ba(Av.622.94),Sr(Av.153.63),Rb(Av.55.08)and Zr(Av.51.86)relatively similar in composition to UCC.High SiO_(2)but low other major oxides signify high mobility during processes of weathering.This was confirmed by high value(>80%)for indices like chemical index of alteration,chemical index of weathering,plagioclase index of alteration,mineralogical index of alteration and relatively lower values for weathering index of parker,recently used alpha indices(α^(Al)_(E))of sodium(326.17α^(Al)_(Na)<344.40),magnesium(100.54α^(Al)_(mg)<398.55),calcium(12.07α^(Al)_(Ca)<198.99),potassium(4.43α^(Al)_(K)<64.33),strontium(0.84α^(Al)_(E)<21.40),barium(0.45α^(Al)_(Ba)<10.52)and rubidium(0.0008α^(Al)_(Rb)<0.06),supported by AI_(2)O_(3)-(CaO^(*)+Na_(2)O)-K_(2)O and CIA vs.SiO_(2)plots that imply intense weathering in the source area.The obtained high CIA values(>80)indicates a steady-state of weathering under a warm/humid climate as confirmed by the SiO_(2)vs.Al_(2)O_(3)+K_(2)O+Na_(2)O plot.High average SiO_(2)(75.41wt%)with K_(2)O/Na_(2)O ratio>1(15.63),low Fe_(2)O_(3)(1.27wt%),Al_(2)O_(3)(15.82wt%)and TiO_(2)(0.46)suggest passive margin tectonic setting.This is supported by enrichedΣREE(209.64 ppm),ΣLREE(195.78),LREE/HREE(27.78)and negative Eu/Eu^(*)(0.68),plots of log(K_(2)O/Na_(2)O)vs.SiO_(2)and SiO_(2)/Al_(2)O_(3)vs.K_(2)O/Na_(2)O.Major elements discriminant-function multi-dimensional diagram,DF1(arcrift-col)vs.DF2(arc-rift-col),for high-silica sediments revealed a continental rift tectonic setting.Thus,the Patti Formation sandstone underwent a high degree of weathering under a humid climatic condition within a continental rift tectonic setting.展开更多
文摘According to the drive of planetary-scale upper magma fluid motions associated with the core-magma angular momentum exchange in the early Earth’s interior, this paper reviewed the results of continental drift studied over the last three decades. The theoretical speculation is in good fit to the traces of geological events left on the Earth’s surface. A northeastward drift directionality of the Australian, African, and South American continents relative to the Antarctica Continent in the Southern Hemisphere is reanalyzed according to the slowing down of the early Earth’s rotation. Six traces of significant back-and-forth drifts of the Australian and Asian continents left respectively on the Southwest and Northwest Pacific seafloors are reidentified according to the gradually decreasing amplitude of core-magma angular momentum exchange during early geological evolution. Finally, the thickening and shortening of different continents during the early drift processes are re-simulated by using a simple magma fluid dynamical model.
文摘Intrinsic magmatic processes are considered as critical operators of plate movements. Here we demonstrate the role of extrinsic processes consequent to intrinsic processes as a catalyst for anomalous rapid plate movement. The rapid and accelerated flight of the Indian subcontinent since Deccan volca- nism until its collision with Eurasia remains as one of the geological conundrums. Data on seismic to- mography, peninsular geomorphology and inferences on continuum of subcrustal structures are utilized to address this enigma. We propose geomorphic isostasy as the mechanism that has driven this fastest drift ever recorded in geological history. It was initiated by sudden instability after the Deccan volcanism and resultant extensive accumulation of lava pile over continental lithosphere of northern India, northern-eastern tilt due to crustal thickness heterogeneity and subcrustal thermal stratification. The drift was sustained by Carlsberg and Central Indian ridge-push until collision and sediment top loading at northeast thenceforth. These inferences and geomorphic isostasy as a catalytic mechanism necessitate variability of drift rates as integral inputs for any continental scale modeling.
文摘Sandstones sampled from Patti Formation,Southern Bida Basin,were studied geochemically using Inductively Coupled Plasma Atomic Emission Spectrophotometer(ICP-AES)and an Inductively Coupled Plasma Mass Spectrometry(ICP-MS)technique to evaluate their weathering and tectonic setting as well as to deduce the paleo-climatic conditions that existed during their deposition.Geochemically,SiO_(2)range from 73.9%to 86.2%,Al_(2)O_(3)(6.7%~17.1%),Fe_(2)O_(3)(1.1%~1.9%),K_(2)O(0.1%~0.7%)while MgO,CaO,Na_(2)O,P_(2)O_(5),MnO and TiO_(2)were<1%.Enriched in Ba(Av.622.94),Sr(Av.153.63),Rb(Av.55.08)and Zr(Av.51.86)relatively similar in composition to UCC.High SiO_(2)but low other major oxides signify high mobility during processes of weathering.This was confirmed by high value(>80%)for indices like chemical index of alteration,chemical index of weathering,plagioclase index of alteration,mineralogical index of alteration and relatively lower values for weathering index of parker,recently used alpha indices(α^(Al)_(E))of sodium(326.17α^(Al)_(Na)<344.40),magnesium(100.54α^(Al)_(mg)<398.55),calcium(12.07α^(Al)_(Ca)<198.99),potassium(4.43α^(Al)_(K)<64.33),strontium(0.84α^(Al)_(E)<21.40),barium(0.45α^(Al)_(Ba)<10.52)and rubidium(0.0008α^(Al)_(Rb)<0.06),supported by AI_(2)O_(3)-(CaO^(*)+Na_(2)O)-K_(2)O and CIA vs.SiO_(2)plots that imply intense weathering in the source area.The obtained high CIA values(>80)indicates a steady-state of weathering under a warm/humid climate as confirmed by the SiO_(2)vs.Al_(2)O_(3)+K_(2)O+Na_(2)O plot.High average SiO_(2)(75.41wt%)with K_(2)O/Na_(2)O ratio>1(15.63),low Fe_(2)O_(3)(1.27wt%),Al_(2)O_(3)(15.82wt%)and TiO_(2)(0.46)suggest passive margin tectonic setting.This is supported by enrichedΣREE(209.64 ppm),ΣLREE(195.78),LREE/HREE(27.78)and negative Eu/Eu^(*)(0.68),plots of log(K_(2)O/Na_(2)O)vs.SiO_(2)and SiO_(2)/Al_(2)O_(3)vs.K_(2)O/Na_(2)O.Major elements discriminant-function multi-dimensional diagram,DF1(arcrift-col)vs.DF2(arc-rift-col),for high-silica sediments revealed a continental rift tectonic setting.Thus,the Patti Formation sandstone underwent a high degree of weathering under a humid climatic condition within a continental rift tectonic setting.
