Diatexite Disaggregation and Shearing, Dom Feliciano Belt, Santa Catarina, Brazil
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| This page is divided into sections representing different processes: different styles of source disaggregation, with particular focus on disaggregation of amphibolite layers, syn-magmatic shearing of diatexite, folding of migmatites during magmatic flow, and finally examples of the flow of magma through diatexites. |
Disaggregation: different styles
Physical disaggregation of protolith by breaking clasts: brecciation. | 
Physical disaggregation through viscous flow. Notice gradual changes from source (left) to magma (right). |
Flow of magma pulling out individual grains and small blocks from schollen. Contact between Corre Mar and Itapema Granite. |
Disaggregation of amphibolite layers in the source
 The Camboriú Complex underwent extensive partial melting and disaggregated to form diatexites known as Itapema Granite. Amphibolite layers disaggregate into a magmatic breccia with rounded to angular blocks of amphibolite inside an otherwise coherent, stromatic gneiss. |
Different melting behaviours between gneiss and amphibolite layers inside Camboriú Complex. Example of net veining of an amphibolite layer. Praia das Taquaras. |
Layer of amphibolite disaggregated into a diatexite/breccia layer. Outcrop in Interpraias road. |
Amphibolite blocks being pulled apart within a mobile felsic diatexite: white leucocratic granite with peritectic Hbl (partial melting of amphibolite) are stretched in between the blocks. Syn-anatectic deformation. Pedreira Cazeca, Camboriú. |
Syn-magmatic shearing of diatexite
 Syn-magmatic shearing of amphibolite schollen and schlieren in Itapema granite. Vila do Areal, near Itapema Beach. |
In situ, dextral shearing in horizontal plane showing S-C-C' planes in heterogeneous Itapema granite. Vila do Areal, near Itapema Beach. |
In situ, thrusting shearing in vertical plane showing S-C planes and asymmetric schollen, Itapema granite. Vila do Areal, near Itapema Beach. Vertical scale: 1.5m. |
Disaggregation of amphibolite, top-to-left shearing. |
Amphibolite sigma-shaped schollen in heterogeneous granite. Vertical wall, thrust to the left, Itapema granite. Praia do Estaleirinho. |
Block of Camboriú stromatic migmatite inside Itapema Granite, sheared at the margins. |
Isoclinal folds in layered migmatite sheared top-to-right, vertical wall. Pedreira Cazeca. |
Delta clast of amphibolite inside a sigma-shaped leucosome, top-to-right. Pedreira Cazeca. |
Flow and folding of narrow amphibolite layers around an angular block of amphibolite in diatexite. Pedreira Cazeca. |
Sheared migmatite gneisses, top-to-left shear sense. Pedreira Cazeca. |
Angular to rounded large blocks of amphibolite with flowing veils of felsic granite around them, top to the right sense, exagerated by cut effect. Pedreira Cazeca. |
Sheared migmatite gneisses, top-to-right shear sense. Praia das Taquaras. |
Folding of migmatites
Both dextral and sinistral shear zones on axial plane of fold, these trend 345 and 005 representing a fan around the fold. Praia do Estaleiro. | 
Beautiful fold with converging axial planar cleavage filled with melt. Praia do Estaleiro. |
Hinge zone of a fold with merging axial planar leucosomes. Praia do Estaleiro. |
Magma channel with rounded schollen trending N15E, roughly parallel to the axial plane of folds in previous photo. Praia do Estaleiro. |
Sinistral antithetic shear zones in general dextral shearing associated with folding. Taquara do Sul. |
Antithetic sinistral shear zones breaking up a schollen inside granite undergoing dextral shearing. Ponta do Corre Mar. |
Flow of magma through diatexites
Hbl-bearing, felsic granitoid intruding shear zones defining lithons in between. Lithons are also magmatic and Hbl bearing but more mafic than the intruding magmas. Vila do Areal. |
Intense flow foliation and stretching of schlieren in betwen two rigid schollen. Praia do Estaleiro. |
Large amphibolite block broken up by intrusive diatexite forming a clast in shear flow. Praia das Taquaras. |