The studied locality covers an area of 120 km2, located at south and southwest of the Hamedan city. The porphyritic granite is the dominant volume of this intrusive body. This granitoid is divided into the granites (monzogranites, syenogranites and alkali feldspar granites) and granodiorites from petrographic point of view. The major part of the study area have magmatic-sub-magmatic fabric and few of the samples show high temperature solid state deformation with presence of chess-board quartz, bending and kink band of biotite and mineral size decreasing from microstructural point of view. The total numbers of 450 oriented core samples were collected from 107 stations, to study the anisotropy of MAGNETIC SUSCEPTIBILITY. The total average SUSCEPTIBILITY for all samples were 114-314 mSI and the mean SUSCEPTIBILITY (Km) of granodiorites was 457.5 mSI, and it ranges from 282-633 μSI, which is higher in compare to granites. This difference is due to the presence of magnetite grains in granodiorites, which has been proved by heavy mineral analysis. The magnetite comprises 0.01-0.025 % of total volume in these rocks. The Km normally varies from 14-514 mSI and indicates the paraMAGNETIC type of granites. The P values vary from 0.72-7.4 %. The T values in most of the samples is positive (T>0) and show planer nature of most of the intrusive body. The high degree of dipping of MAGNETIC foliation and lineation at the central part of the intrusive body, which decreases with increasing distance from center of the intrusive body, may indicate the location of feeding. This characterization can be seen at two other places addition to the center. On the basis of MAGNETIC parameter and other factors such as dominant transpression tectonic regime in this area, one can say that the ascending magma was due existing of stretching environment with NW-SE trend, and this can be proved by direction of MAGNETIC lineations at the same direction. The differences in the direction of NE-SW, which some of the studied sites show, may be due to rotation of MAGNETIC body during injection and emplacement in response to prevailing tectonic forces in studied area and viscosity of magma.

Bouin- Miandasht granitoid pluton with an area of 40 Km2, outcropped in the north of Bouin Miandasht- Aligoudarz road, was emplaced into Triassic to early Jurassic low to medium grade metapelitic rocks of Sanandaj - Sirjan structural zone. This pluton composed of alkali feldspar granite to leucogranite. For the first time, variation of anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)) is applied to investigate MAGNETIC fabric of this pluton. The Mean MAGNETIC SUSCEPTIBILITY values (Km in mSI) of the different rock groups of Bouin- Miandasht pluton are as follows: alkali feldspar granites (158), fine granites (120), coarse granites (166), and leucogranites (34). The lower Km values for the main compositions of this pluton (< 500 mSI) suggesting the paraMAGNETIC nature of these granites. Biotite is the main carrier of MAGNETIC properties in the studied rocks. The MAGNETIC anisotropy (P %) varies from 1 to 15. Aalkali feldspar granites have the highest P value and show positive correlation with degree of deformation. Shape parameter of MAGNETIC ellipsoid (T) values varies from -0.43 to 0.85 and most of the MAGNETIC ellipsoids are oblate. Seventy five percent of specimens have positive T value. This subject indicates that MAGNETIC ellipsoids are oblate and then foliation is prevailing, and also field evidence confirms this conclusion.

2The granitoid pluton is located about 90 km northwest of Zahedan, in the highest part of the Zahedan-Saravan magmatic belt. Compositionally, the pluton is biotite granite and granodiorite. The rocks forming the northern and southern parts of the pluton have magmatic to sub-magmatic fabric. In addition, our study show low to high temperatures solid-state deformation, such as bulging and chessboard in quartz, myrmikite texture and sliding in biotite. 519 directional cores from 70 stations were collected from the studied area for anisotropy of MAGNETIC SUSCEPTIBILITY studies. The mean SUSCEPTIBILITY (Km) is from 10-301 µSI. Biotite is the main mineral for MAGNETIC SUSCEPTIBILITY in the pluton; where the percentage varies in different parts of the pluton. The P values vary from 0.8-15.5 percent. The T values in most samples are positive and show planner nature. The high degree of dipping of MAGNETIC foliation and lineation, MAGNETIC foliation throughout the pluton are on average from 31 and 60 degrees and shows the northwest-southeast trend. The parallel extension of the lineation with the margin of the pluton and the presence of nearby metamorphic rocks show that during the injection of magma, biotite granite and granodiorite were emplaced parallel to the schistosity of the host rock. In the pluton, the area has MAGNETIC lineation, where a high dip is the main place of magma injection, which is located in the center of the pluton, and other parts can be sub-sites of feeding the pluton. Based on the field observations and MAGNETIC evidence, the parent magmas of the Garagheh granitoid pluton are emplaced as a laccolith with a dip of 45 degrees in the northeast.

Zafarghand granitoid pluton with compositional range from gabbro to granite and early to middle Miocene age cropped out about 35 km of SE Ardestan. This pluton intruded the Eocene volcanic and volcanosedimentary rocks of the Urumieh - Dokhtar structural zone. In this research, for the first time, the emplacement mechanism of Zafarghand granitoidic pluton method has been investigated using of anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)). Based on field observations, as well as petrography and interpretations of MAGNETIC parameters, Zafarghand pluton divided into 5 domains (1A, 1B, 2, 3, 4 and 5). Domain 1, in turn, is divided into 1A and 1B. Domains 2 and 4 are lithologically, gabbro to quartzdiorite and have been emplaced first. They have played as feeder zones. Domains 1A, 1B, 3, and 5 are dominantly granodioritic to granitic composition and have been emplaced as a big and low dip magmatic flow (or possibly as a sill). The occurrence of gabbro to quartzdiorite as well as grandiorite, granite and tonalite in the margin borders of the body, are all indication of magma mixing. It is should be noted that during emplacement of the pluton studied, fractional crystallization, magma mixing and crustal contamination contributed to its generation and the evolution as well.

Intruduction: Red beds have been widely studied by palaeoMAGNETIC methods for what they can tell us about the history of sedimentary basins and their subsequent deformation (Collinson, 1974, Turner, 1979a, b and 1981, McCabe and Elmore, 1989, Elmor, et al., 1993 and 2000). This study has investigated the palaeomagnetism of the Cambrian red sediments (Dezou and Dahou Formation) of the eastern margin of Central Iran.Davoudzadeh and Schmidt, (1984), have done some work on the region which includes these rocks and discuss the few rotations of the Central Iran micro plates. The aim of this study is to consider the (AMS) results to investigate the palaeo force field on the rock located at the northern side of the Persian Gulf.Geological setting: The sampling sites of this study are situated in the Cambrian sediments of the eastern margin of Central Iran. These are the largest structural sedimentary units and are composed of complex geological structures. In this region, igneous, metamorphic and sedimentary rocks of the Precambrian to Quaternary Periods are preserved with a predominant number of outcrops of Mesozoic rocks. Most structural elements in different scales such as faults and folds are related to the tectonic activities of the Mesozoic and later eras. The most important structural element of the region is the Koohbanan fault with a NW-SE trend. Similar to the most other important faults of Central Iran, the existence of this fault is related to the late Precambrian Era.The Dezou Formation is limited to the Rezou series (Late Precambrian) by a fault at the bottom and it can be separated by an unconformity from the Dahou Formation at the top in its area of study (Gazooie village, 30.8o N and 56.7o E, sites 13-14 & 16-20). It has a thickness of 380 m involving three major parts.The Dahou Formation in the area of study (Gazooie village, 30.8oN and 56.7oE, site 20, figure. 4) rests with a basal breccia conformably on dolomites and limestone of the Dezou Formation. Middle to the end of early Cambrian Period was inferred from the stratigraphic position. It is covered by the Koohbanan Formation unconformably.Rock MAGNETIC studies: In the present study rock MAGNETIC experiments including IRM acquisition, backfield IRM, thermoMAGNETIC, and hysteresis and (AMS) studies have been performed on samples of the Dezou and Dahou Group sediments. Some of these experiments yield results that are grain size dependent and others are mineral type dependent; some are dependent on both properties.Jelinek (1981) and Hrouda (1982) have proposed parameters T and Pj for the shape and corrected anisotropy degree (Tarling and Hrouda, 1993). A plot of T against Pj when Pj>1 and-1<T<1 provides information about the shape and the degree of anisotropy on the same plot. T- Pj plot is shown for all sampling sites in the Dahou and Dezou Formations and also site 20 only. Most samples have less than 10% anisotropy but some of the samples tend to be more anisotropic.Curie temperatures are mostly between 675-700oC and attributed to specularite and pigments of hematite. In a few examples magnetite with a Curie temperature of about 570ºC can be seen as well. The clearest indication of magnetite here is RM ratio (RM ratio is the value of Ms at 100°C on the cooling curve to the value on the heating curve).RM ratio < 1 showing that magnetite has been oxidized to hematite with low Ms Values.Rock MAGNETIC studies show an agreement that both specular hematite and magnetite can occur in these sediments although the effect of hematite is usually dominant.Site 13 that is sampled in red sandstone shows paraMAGNETIC mineral content and hematite pigment with a Curie temperature of 680oC and a saturation field of 2000 mT. Low coercivity of 50 mT shows a low amount of magnetite.Site 14 that is sampled in red sandstone shows a high amount of paraMAGNETIC mineral content and finer grain size of hematite pigments (compare to site 13) with a Curie temperature of 680oC and a saturation field of 3000 mT. Lower coercivity than site 13 shows low amount of magnetite too.Site 15 that is sampled in dolomite breccias shows very scattered results of IRM, hysteresis and Curie curves. And overall look suggest a predominantly diaMAGNETIC mineral.Site 16 that is sampled in red sandstone at its contact with dyke shows an overprinted magnetite mineral and it is obvious from the curie temperature of 580oC and very low saturation field in hysteresis and IRM curve.Site 17 that is sampled in dolomite just above the dyke shows an overprinted magnetite.However, a predominant content of diaMAGNETIC minerals is clear.Site 18 and Site 19 that are sampled in red sandstone and red shale respectively show similar rock MAGNETIC behavior of paraMAGNETIC mineral content and pigment and specular hematite with a high saturation field of 3000 mT and a back field of 500 mT.Red sediments normally show a stable rock MAGNETIC content. The presence of hematite in these samples that is evident from rock MAGNETIC results also confirms the stability of MAGNETIC properties and therefore we can rely on the (AMS) directional analysis.Conclusion: Anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)) studies on Precambrian to early Cambrian red sediments, in the north side of the Kohbanan fault (Iran), show a predominant tectonic fabric with a low magnitude of oblate and prolate shape. The direction of the maximum axis of (AMS) lies parallel to the direction of the folded bed axis and therefore tectonic forces are probably matched up with the rotation of the Lut plate with respect to the Central Iran.

Chah Zard granitoid pluton with 535. 4± 3. 2 Ma age (U-Pb zircon method, carried on the Zircon) intruded into Jandagh – Arousan metamorphic complex, and strongly mylonitized during later events. For the first time, Chah Zard granitoid pluton investigated by anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)) method. Mean MAGNETIC SUSCEPTIBILITY (Km) of biotite granites (the main constitute of Chah Zard granitoid pluton) is 112 µ SI. Biotite is the most important MAGNETIC carrier in biotite granites. During of mylonitization, considerable volume of biotite alterated or evolved to muscovite and then Km values of their bearing rocks strongly decreased. MAGNETIC lineation and foliation have low plunge and dip, respectively, and also field evidences confirmed this finding. MAGNETIC lineations, mostly oriented toward northwest. Since the intensity of mylonitization is very high, microstructures which resulted in relation to tectonically stresses, had overcome to magmatic microstructures and partially to completely oblitrated them.

The analysis of Anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)) is a powerful and rapid technique to examine the preferred orientations of mineral (MAGNETIC) fabrics and can indicate the nature of a magma transport (vertical or lateral). The relationship between MAGNETIC fabric and geometry of a dyke swarm enables us to understand magma emplacement processes. Depending on the mutual relationship of MAGNETIC fabric and individual dyke geometry, mode of magma transport is interpreted. The knowledge on the nature of magma transport combined with information on geometry, magmatic overpressure and geochemistry enable us to comment on dyke emplacement processes, the location of possible feeders, syn-emplacement and post-emplacement deformations and prevailing stress regime during emplacement. A number of dykes and dyke swarms have been emplaced into the Indian shield at different points in time. Their ages vary from the Mesoarchean to Tertiary. We present here a review of three case studies where (AMS) technique was applied to the samples collected from Indian dykes. Two case studies are on the Proterozoic dykes that intruded into the Dharwar craton and the third case study is on Mesozoic dykes that punctured the South Indian Granulite Terrain (SIGT). The dykes generally show ― normal‖ anisotropy fabric to indicate vertical magma emplacement with few exceptions where lateral/inclined magma flow was suggested or the results were inconclusive. We present here a critical review on the interpretation of such ― anomalous‖ fabrics and comment on further studies that can be carried out to extract more information from such results.

Challu granitoid pluton is located in southeast of Damghan and northern part of central Iranian structural zone. Intrusion of the pluton into volcanic and volcanic-sedimentary rocks and the resultant hydrothermal fluids has caused alteration and Fe mineralization. Generally, two different phases of propylitic and argillic alterations are identified in the studied pluton. MAGNETIC SUSCEPTIBILITY of fresh and altered rocks at the Challu granitoidic pluton is measured by MAGNETIC fabric technique. The average measured MAGNETIC SUSCEPTIBILITY has been obtained about 28872± 3410 μ SI for monzodiorite and 21487 ± 3916 μ SI for quartzdiorite. Circulation of hydrothermal fluids throughout the intrusive body has caused the main mineral compositions variation and changed the MAGNETIC properties of minerals as the average measured MAGNETIC SUSCEPTIBILITY for the above rocks has, respectively, been reduced to 25117± 988 μ SI and 6262± 1577 μ SI, due to propylitic and argillic alteration. Different kinds of opaque minerals in the pluton have also been identifined by thermoMAGNETIC curves as MAGNETIC SUSCEPTIBILITY changes with temperature. These results show how magnitude of MAGNETIC SUSCEPTIBILITY decreases during alteration due to removal or reducing in the size of magnetite or its convertion to hematite.

The measurement of anisotropy of MAGNETIC SUSCEPTIBILITY is a suitable technique for quantifying the MAGNETIC fabric of a pluton using cores with 25 mm diameter and 50 to 100 mm length. The origin of MAGNETIC fabrics in granites is mainly described in terms of orientation of crystals, which occurred during defonnation of cooling magma before its complete crystallisation.In this paper, principles of anisotropy of MAGNETIC SUSCEPTIBILITY ((AMS)) and its applications in determination of MAGNETIC fabrics of Shah-Kuh is presented. The magnitude of MAGNETIC SUSCEPTIBILITY in different units of this pluton ranges between 79 to 2896µ SI. These values, as well as Fe-content in different specimens, indicate that minerals responsible for anisotropy of MAGNETIC SUSCEPTIBILITY are mainly magnetite, hornblende and biotite, in lesser significance. Accordingly, Shah-Kuh granite, except its greisenic granite and leucocratic microgranite, could be classified as ferroMAGNETIC granite. This conclusion confirms the earlier petrological studies, which classified Shah-Kuh granite as an I- type granites. The presence of tourmaline in the greisenic granite and leucocratic microgranite results in an inverse MAGNETIC fabric. Such rocks, due to their inverse MAGNETIC fabric, need more detail (AMS) study. Nearly vertical MAGNETIC foliation, observed in the some specimens, probably represents their primary location in the wall of pluton. Specimens with vertical MAGNETIC lineations, from granodiorites adjacent to of Deh- Margh village, may be evidence of magma feeder zone.