GMPV48Mantle roots of deep seated magmas. Origin and evolution of layered mantle lithosphere in different geodynamic settings
|Conveners: Igor Ashchepkov , Evgenii Sharkov | Co-Convener: Yana Fedortchouk|
Description of section. Possible topics
Mantle roots of deep seated magmas
Mantle inclusions in different types of the magmas in intraplate, arc and oceanic island magmatism containing major information about composition, structure and processes of mantle evolution in different tectonic settings. Magmas are sampling mainly their way to the surface and allow to reconstruct the polybaric conduit and chamber systems and wall rocks. The mechanisms of melt mantle magmas transformation during their rise.
Intraplate magmatism allows to judge about composition and thermal conditions and heterogeneity of the mantle and it modification by plume and subduction related melts. Magma compositions depend on structure of magmatic systems, and changing their primary features due to differentiation, mixing and contamination by country rocks.
Key questions are.
1. Subdivision from the xenoliths sets primary varieties and melt modified types in the different levels of mantle columns. Reconstruction of primary mantle layering and position of the fusion zones primary host rock composition, PTXFO2 conditions, degree of hydration and accounting the chemistry and the physics of intruding melts and deriving fluids.
2. Dynamics of the developing of melt conduits accounting mantle layering.
3. Role and mechanism of presiding metasomatism in the transformation of mantle melts.
The questions for xenoliths in alkali basalts: (1) depth of the generation of mantle diapirs and mechanism of the emplacement and divergence of the mantle material during uplift
what was the reason of rising of structure of mantle diapirs and possible role of the plumes (or fluid flows) in their generation. 3 The Key questions for xenoliths from the cratonic lithosphere are: (1) signs and methods of mantle layering detection changes of mantle and variations of lithology in space in time using petrological, geochemical and geophysical techniques; (2) growth mechanisms of the continental lithosphere accounting the melting of submerging slabs and possible interaction with plums and rising melts; (3) types of mantle metasomatism and their relationship to tectonic setting; (4) mechanisms of melt migration through the lithosphere, etc.
The special interest is also spatial and compositional distribution of magmatic system within large igneous provinces (LIPs); (5) evolution of LIPs in time and its reasons.
Layering of the craton keel.
Thermobarometric evidences of the discontinuities in the subcratonic lithospheric mantle (SCLM) (Griffin et al., 1996-2011; O’Reilly et al 1986; Bell et al., 2003; Rudnick et al ., 1999; Kopylova et al ., 1999 ; Lehtonen et al ., 2004; etc ). The comparison of the different methods and thermobarometric models in application to the mantle layering (Nimis, Grutter, 2010 etc. Grutter et al., 2009 ). Reasons of the division if the mantle sequences in upper and lower part at 40-35 kbars (Ashchepkov et al., 2010). The agreement and disagreement of the thermobarometric with the lithosphere thickness obtained with geophysical methods (Pristley, McKenzie, 2006 etc). Evolution of the geothermal mantle regime in time (Ashchepkov et al 1986; Artemieva, 2009; 2012 )
2. Influence of the plumes or large mantle magmatic bodies of the geothermal regime (Smith, Lewis, 1999; Artemieva et al., 2012; Smith et al., 2009. Ayalew, Gibson,2009 etc).
3.Geochemical features of the separate startigraphic units or layers in SCLM and the possible interpritaion of their origin (Ionov et al., 2010 ). The geodynamic models of their original occurrence of the separate layers (Pearson, 1998; Jacob et al., 1993-2009). Comparison of the mantle sequences in different tectonic terrains within craton (Ashchepkov et al., 2011).
4.The evidences of the craton keel modification by the different type of metasomatism and interaction with the plum melts (Zhang, Duan, 2009; Ionov et al ., 2006; Tappe et a; ., 2007).
5.Dynamic of the craton keel destruction by the subduction tension accompanied by the weakening due to hydration by subduction related fluids (Xu,2001; Zhang et al ., 2005; Deng et al ., 2007 etc).
6.The models of the craton SCLM growth (Snyder, 2002; Snyder et al., 2009; Griffin et al., 2003-2010). Changes of the mechanisms of craton growth and destruction in time (Lee et al., 2010).
7.The PT facies of the mantle metasomatism for the different geodynamic environment (Magna et al ., 2008; Qin et al.,2010; Gregoire et al ., 2001; 2002,2003; Beccaluva et al., 2004; Matsumoto, et a ., 2000; Arai et al ., 2000-2010 etc ).
8.Types of the mantle peridotites and their origin in n different geodynamic settings (Bazylev, et al ., Ionov et al ., 1993-2010; Zheng et al ., 2008-2011; Wittig et al., 2008; Ntaflos et al., 2010; Hidas et al., 2007; ; Batanova et al., 2008 ).
9.Compositional major and trace element difference between garnet and spinel peridotites in various geodynamic environment in ancient and modern time and influence of the PT conditions to the compositions (McDonough, Sun, 1995; Robinson, Wood, 1998; Glaser et al ., 1999; Canil, 2004;Ionov et al., 2005; Zhang et al ., 2003;2008, Schmädicke et al., 2011 ). Problem of primitive mantle peridotites – ancient unmodified primordial mantle and refertilized by the anatexic of plum melts.
10.Eclogites. Types of eclogites and their origin – TGG cumulates or restites (Horodyskyj ey al ., 2007), subducted basalts or sediments. Special type of deep seated cumulates or metasomatites. Distribution of eclogites in mantle sequences in cratonic keel (Sobolev et al., 1987; (Jagouts et al , 1993; Snyder et al., 1993, Wyman, Kerrich, 2009; Spetcius et al.,2009;). Thermobarometry of the eclogites and their role in the mantle layering (Simakov, 2008; Brey et al., 1986 Peackly et al ., 2011). The role of eclogites in production of mantle melts and their hybridism with the plume melts (Sobolev et al ., 2006) Responsibility of the eclogites for the diamond grade (Sobolev et al., 1974- 2009).
11.Types mantle pyroxenites anatexic, magmatic. (Pokhilenko et al., 1999; Downes et al., 2007; Zhang, et al ., 2007; Aulbach et al ., 2009; Tinguely, et al ., 2008 Ashchepkov et al., 2011 ) Plume related and subduction related pyroxeniets their role in mantle layering and production of mantle melts.
12.Traps for the mantle melt in the SCLM. Lower 65-55 kbar for ultramafic, Middle 40 kbar for carbonatites, upper 30- 20 kbars for hydrous silicate melts (Tappe at l., 2007; Foley et al., 2011).
13 .Detection of mantle layering (Snyder et al., 2009) and subduction slabs (Koulakov et al., 2001-2010; Bonnardot et al., 2009; King et al ., 2007 Currie, et al., 2004 etc) in the mantle by geophysical methods. Correspondence between geochemical reservoir, geophysical discontinues and petrological or models of mantle (Anderson, 1995; Puchtel et al ., 1999 Korenaga, 2009; Hofmann. 2007 ).
14. Agreement between the S, SP, P – PP models for the detection of the mantle layering (Xu et al., 2008; Mooney, 2007; Chekunov et al ., 1997; Beloussov et al ., 1980). Geophysical models for mantle – compositional variations, presence of melt fluid (Braun, 2000; Walter, 2007; Schiano, 2003)or anisotropy of mantle rocks (olivine orientation as the result of flowing (Gatzemeier, Tommasi, 2006; Ismaı̈l, Mainprice, 1998).
15.Basalt geochemical features as the indicator of the difference in the mantle source lithology (Russo et al ., 2009; Sheth, 1999; Niu, et al ., 2002; Xu eta al., 2002; Jerram, Widdowson,2005 etc ).
16. Isotopic mantle domains and isotopic mantle stratification.
17. Mantle magmas as the source of the information for the mantle stratification and temporal and special evolution of mantle lithosphere
18. Oxygen state of the mantle rocks. The fluctuations and of the oxygen fugacity and mechanism of their modifications.