scholarly journals Paleogene-early miocene deformations of Bukulja-Vencac crystalline (Vardar zone, Serbia)

2007 ◽  
pp. 9-20 ◽  
Author(s):  
Milun Marovic ◽  
Ilija Djokovic ◽  
Marinko Toljic ◽  
Jelena Milivojevic ◽  
Darko Spahic

Low-grade metamorphic rocks of the crystalline of Mts. Bukulja and Vencac, which are integral parts of the Vardar Zone, are of Late Cretaceous age. From the Middle Paleogene to the beginning of the Miocene, they were subjected to three phases of intensive deformations. In the first phase, during the Middle Paleogene, these rocks were subjected to intense shortening (approximately in the E-W direction), regional metamorphism and deformations in the ductile and brittle domains, when first-generation folds with NNE-SSW striking fold hinges were formed. In the second phase, during the Late Oligocene and up to the Early Miocene, extensional unroofing and exhumation of the crystalline occurred, which was followed by intrusion of the granitoid of Bukulja and refolding of the previously formed folds in a simple brachial form of Bukulja and Vencac with an ESE-WNW striking B-axis. The third phase was expressed in the Early lowermost Miocene (before the Ottnanghian), under conditions of NE-SW compression and NW-SE tension. It was characterized by wrench-tectonic activity, particularly by dextral movements along NNW-SSE striking faults.

2003 ◽  
Vol 140 (4) ◽  
pp. 421-441 ◽  
Author(s):  
UWE RING ◽  
CHRISTOPHER JOHNSON ◽  
RALF HETZEL ◽  
KLAUS GESSNER

Thermochronological data reveal that the Late Cretaceous–Tertiary nappe pile of the Anatolide belt of western Turkey displays a two-stage cooling history. Three crustal segments differing in structure and cooling history have been identified. The Central Menderes metamorphic core complex represents an ‘inner’ axial segment of the Anatolide belt and exposes the lowest structural levels of the nappe pile, whereas the two ‘outer’ submassifs, the Gördes submassif to the north and the Çine submassif to the south, represent higher levels of the nappe pile. A regionally significant phase of cooling in the Late Oligocene and Early Miocene affected the outer two submassifs and the upper structural levels of the Central Menderes metamorphic core complex. In the northern part of the Gördes submassif, cooling was related to top-to-the-NNE movement on the Simav detachment, as the apatite fission-track ages show a northward-younging trend in the direction of movement on this detachment. In the Çine submassif, relatively rapid cooling in Late Oligocene and Early Miocene times may have been related to top-to-the-S extensional reactivation of the basal thrust of the overlying Lycian nappes. The second phase of cooling in the Anatolide belt is related to Pliocene to Recent extension resulting in the formation of the Central Menderes metamorphic core complex in the inner part of the Anatolide belt. Core-complex development caused the formation of supra-detachment graben, which document the ongoing separation of the Central Menderes metamorphic core complex from the outer submassifs.


1987 ◽  
Vol 124 (2) ◽  
pp. 121-133 ◽  
Author(s):  
G. J. Nichols

AbstractThe Aguero fanglomerate body developed in late Oligocene to early Miocene time at the northern margin of the Ebro Basin where the emergent southern Pyrenean thrust front created a topographic high. Tectonic activity in the thrust belt strongly influenced the sequences and structures within the fan deposits. The fan deposits display an initial coarsening-up sequence. Intraformational unconformities subdivide the proximal sediments into a series of wedges. These result from a continued uplift along the thrust front during the initial stages of fan development. A major intraformational unconformity marks the top of this sequence and the start of a fining-up sequence. Further tectonic activity in the thrust front is indicated by a syn-depositional synclinal fold which decreases in amplitude up sequence. Rejuvenation of fan sedimentation to form a second coarsening-up sequence reflects renewed activity in the thrust front. This second sedimentation event resulted in a plus 200 m thickness of massive conglomerates. The geographical limits of fan sedimentation can be determined because the fan deposits are lithologically distinct from the other Ebro Basin molasse in the area. The area of the drainage basin of the fan can also be estimated by consideration of the clast types present in the fan deposits. The fan and drainage basin areas are estimated to be 6 km2 and 10 km2 respectively.


1962 ◽  
Vol S7-IV (5) ◽  
pp. 682-690
Author(s):  
Enzo Giannini ◽  
Marco Tongiorgi

Abstract Tectonic activity in the northern Apennines (Italy) is traced from the Oligocene to the Pliocene. The paroxysmal phase, extending from the middle Oligocene into the Aquitanian, was marked by positioning of the Tuscan and Ligurian nappes, shrinking of the crust, and folding of the autochthon. The present general topography of the northern Apennines can be attributed to activity during this phase. During the upper Tortonian second phase, movement was renewed and the two nappes assumed their present positions. The third phase, during the lower Pliocene, was marked by limited gravity sliding.


1983 ◽  
Vol 120 (2) ◽  
pp. 141-152 ◽  
Author(s):  
P. D. Ryan ◽  
M. D. Max ◽  
T. Kelly

Summary16 samples of Ordovician basic volcanic rocks of the South Connemara Group, which abut the southern side of the metamorphic rocks of the Connemara massif in western Ireland, have been analysed for both major and trace elements. Although subject to low grade regional metamorphism and subsequently hornfelsed by the Galway Granite (400 Ma), their immobile element contents do not appear to be significantly disturbed. These elements characterise the metabasites of the South Connemara Group as ocean floor basalts having their origins in a marginal basin. The Skird Rocks Fault, separating the South Connemara Group from high grade metamorphic rocks of the Connemara massif, is consequently regarded as the northern margin of the vestiges of the lapetus Ocean which can be traced into, and along, the Southern Uplands Fault.


Author(s):  
Marc Zimmerman

This chapter discusses U.S. Puerto Rican literature, which can be divided into three phases, preceded by a kind of “pre-phase.” The pre-phase, extending from the last century, consists of exiles from the independence struggle against Spain. These include major intellectuals who mainly wrote about their Caribbean struggles and reflected critically on the New York experience of arriving Puerto Rican nationals. The first phase, extending from 1917 to 1945, is mainly of autobiographical and journalistic works expressing the efforts of first-generation migrants to adjust to U.S. life. The period of migration from 1945 to 1965 constitutes the second phase, when radical exile writers mainly wrote a literature of exile with hardly any bilingualisms and only limited reference to the migration experience. Lastly, the third phase “effectively draws together the firsthand testimonial of the ‘pioneer’ stage and the fictional, imaginative approach of the writers of the 1950s or 1960s.”


2007 ◽  
pp. 21-27 ◽  
Author(s):  
Milun Marovic ◽  
Ilija Djokovic ◽  
Marinko Toljic ◽  
Darko Spahic ◽  
Jelena Milivojevic

This paper presents the basic structural elements of the dome of Veliki Jastrebac, as well as the chronology and mechanisms of the deformational events responsible for its formation. It was determined that the dome of Veliki Jastrebac consists of two large sequences which are, in the vertical section, in the inverse position. The lower part is made of Late Cretaceous and Cretaceous-Palaeogene low-grade to medium-grade metamorphic rocks, which are intruded by Paleogene granitoid (probably the Vardar Zone), which are covered with a large overthrust consisting metamorphics of the Serbian-Macedonian Mass. The low-grade to medium-grade metamorphosed complex of Veliki Jastrebac, with the granitoid, represents a metamorphic core complex, exhumed by mechanisms of extensional tectonics in the Paleogene.


Author(s):  
Gejing Li ◽  
D. R. Peacor ◽  
D. S. Coombs ◽  
Y. Kawachi

Recent advances in transmission electron microscopy (TEM) and analytical electron microscopy (AEM) have led to many new insights into the structural and chemical characteristics of very finegrained, optically homogeneous mineral aggregates in sedimentary and very low-grade metamorphic rocks. Chemical compositions obtained by electron microprobe analysis (EMPA) on such materials have been shown by TEM/AEM to result from beam overlap on contaminant phases on a scale below resolution of EMPA, which in turn can lead to errors in interpretation and determination of formation conditions. Here we present an in-depth analysis of the relation between AEM and EMPA data, which leads also to the definition of new mineral phases, and demonstrate the resolution power of AEM relative to EMPA in investigations of very fine-grained mineral aggregates in sedimentary and very low-grade metamorphic rocks.Celadonite, having end-member composition KMgFe3+Si4O10(OH)2, and with minor substitution of Fe2+ for Mg and Al for Fe3+ on octahedral sites, is a fine-grained mica widespread in volcanic rocks and volcaniclastic sediments which have undergone low-temperature alteration in the oceanic crust and in burial metamorphic sequences.


2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Abdul Hasan Saragih

This classroom research was conducted on the autocad instructions to the first grade of mechinary class of SMK Negeri 1 Stabat aiming at : (1) improving the student’ archievementon autocad instructional to the student of mechinary architecture class of SMK Negeri 1 Stabat, (2) applying Quantum Learning Model to the students of mechinary class of SMK Negeri 1 Stabat, arising the positive response to autocad subject by applying Quantum Learning Model of the students of mechinary class of SMK Negeri 1 Stabat. The result shows that (1) by applying quantum learning model, the students’ achievement improves significantly. The improvement ofthe achievement of the 34 students is very satisfactory; on the first phase, 27 students passed (70.59%), 10 students failed (29.41%). On the second phase 27 students (79.41%) passed and 7 students (20.59%) failed. On the third phase 30 students (88.24%) passed and 4 students (11.76%) failed. The application of quantum learning model in SMK Negeri 1 Stabat proved satisfying. This was visible from the activeness of the students from phase 1 to 3. The activeness average of the students was 74.31% on phase 1,81.35% on phase 2, and 83.63% on phase 3. (3) The application of the quantum learning model on teaching autocad was very positively welcome by the students of mechinary class of SMK Negeri 1 Stabat. On phase 1 the improvement was 81.53% . It improved to 86.15% on phase 3. Therefore, The improvement ofstudent’ response can be categorized good.


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