scholarly journals Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low- to low-grade metamorphism

2015 ◽  
Vol 29 ◽  
pp. 156-174 ◽  
Author(s):  
Silvia Omodeo-Salé ◽  
Ramon Salas ◽  
Joan Guimerà ◽  
Robert Ondrak ◽  
Ramon Mas ◽  
...  
2011 ◽  
Vol 149 (2) ◽  
pp. 208-220 ◽  
Author(s):  
UWE RING ◽  
ARNE P. WILLNER ◽  
PAUL W. LAYER ◽  
PETER P. RICHTER

AbstractWe describe the geometry and kinematics of a Jurassic to Early Cretaceous transpressive sinistral strike-slip system within a metamorphic basement inlier of the Mesozoic magmatic arc near Bahia Agua Dulce at latitudes 31–32°S in north-central Chile and discuss possible relations with the Atacama Fault System further north. Sinistral transpression overprints structures of an accretionary system that is represented by the metamorphic basement. Sub-vertical semi-ductile NNW-striking strike-slip shear zones are the most conspicuous structures. Chlorite and sericite grew, and white mica and quartz dynamically recrystallized, suggesting low-grade metamorphic conditions during semi-ductile deformation. Folds at the 10–100 metre scale developed before and during strike-slip shearing. The folds are deforming a former sub-horizontal transposition foliation that originated during prior accretion processes. The folds have axes sub-parallel to the strike-slip shear zones and sub-vertical axial surfaces indicating a component of shortening parallel to the shear-zone boundaries, suggesting an overall transpressive deformation regime. Transpressive strike-slip deformation also affects Middle Triassic (Anisian) basal breccias of the El Quereo Formation.40Ar–39Ar laser ablation ages of synkinematically recrystallized white mica in one of the shear zones provide an age of 174–165 Ma for the waning stages of semi-ductile strike-slip shearing. The semi-ductile shear zones are cut by mafic and rhyolite dykes. Two rhyolite dykes yield40Ar–39Ar ages of 160.5 ± 1.7 Ma and 131.9 ± 1.7 Ma, respectively. The latter dyke has been affected by brittle faulting. Fault-slip analysis shows that the kinematics of the faulting event is similar to the one of the semi-ductile shearing event, suggesting that sinistral transpression continued after ~130 Ma. Timing, kinematics and geographic position suggest that the shear zones at Bahia Agua Dulce represent a southern continuation of the prominent Atacama Fault System that affected the Jurassic/Early Cretaceous arc over its ~1400 km length.


2021 ◽  
Vol 62 (9) ◽  
pp. 1006-1020
Author(s):  
F.I. Zhimulev ◽  
E.V. Vetrov ◽  
I.S. Novikov ◽  
G. Van Ranst ◽  
S. Nachtergaele ◽  
...  

Abstract —The Kolyvan’–Tomsk folded zone (KTFZ) is a late Permian collisional orogen in the northwestern section of the Central Asian Orogenic Belt. The Mesozoic history of the KTFZ area includes Late Triassic–Early Jurassic and Late Jurassic–Early Cretaceous orogenic events. The earlier event produced narrow deep half-ramp basins filled with Early–Middle Jurassic molasse south of the KTFZ, and the later activity rejuvenated the Tomsk thrust fault, whereby the KTFZ Paleozoic rocks were thrust over the Early–Middle Jurassic basin sediments. The Mesozoic orogenic events induced erosion and the ensuing exposure of granitoids (Barlak complex) that were emplaced in a within-plate context after the Permian collisional orogeny. Both events were most likely associated with ocean closure, i.e., the Paleothetys Ocean in the Late Triassic–Early Jurassic and the Mongol–Okhotsk Ocean in the Late Jurassic–Early Cretaceous. The apatite fission track (AFT) ages of granitoids from the Ob’ complex in the KTFZ range between ~120 and 100 Ma (the Aptian and the Albian). The rocks with Early Cretaceous AFT ages were exhumed as a result of denudation and peneplanation of the Early Cretaceous orogeny, which produced a vast Late Cretaceous–Paleogene planation surface. The tectonic pattern of the two orogenic events, although being different in details, generally inherited the late Paleozoic primary collisional structure of the Kolyvan’–Tomsk zone.


1997 ◽  
Vol 37 (1) ◽  
pp. 136 ◽  
Author(s):  
K. Baxter ◽  
G. T. Cooper ◽  
G. W. O'Brien ◽  
K. C. Hill ◽  
S. Sturrock

Although the petroleum industry is commonly interested in the upper few kilometres of the lithosphere, it is the deeper stretching events which may drive the development of regional thermal perturbations and which may overprint a significant thermal signature onto the shallower section. The Vulcan Sub-basin, which is located in the Timor Sea, northwestern Australia, has undergone a period of rifting during the Late Jurassic and shows a classic transition from intra-continental rifting to passive margin subsidence during the Late Jurassic to Early Cretaceous. A model has been developed of the Late Jurassic rifting history of the basin, which includes the flexural and stratigraphic response, and the development of the Cretaceous to Recent post- rift basin history. Quantification of the associated vertical motion of the lithosphere suggests that the transition is related to increased ductile extension in the lower crust and lithospheric mantle with little attendant upper crustal faulting to record the magnitude of this event in the structural history of the Vulcan Sub-basin. This lack of upper crustal deformation has resulted in an under- appreciation of the importance of this extensional event.By modelling the Jurassic to Recent basin history, a thermal model may be built allowing predictions of palaeo-heat flow during the critical time of hydrocarbon generation. The model predicts that during the Jurassic and Early Cretaceous, increased lower crust and lithospheric mantle extension produced a thermal anomaly of ~20mW/m2 across the Vulcan Sub-basin. The relaxation of this thermal anomaly in the Cretaceous and Tertiary produced a rapid post-rift subsidence which allowed flooding of the margin, with increased subsidence towards the northwest. However, the evolution of this thermal perturbation beneath the upper crust resulted in a time lag between Late Jurassic rifting and maximum basin heat flow in the Early Cretaceous of up to 30 million years after Callovian breakup Therefore, the simple relationship between upper crustal faulting and total lithosphere stretching common in intra-continental rifts is predicted to break dow n immediately preceding conti nental breakup and necessitates modelling of the transition from syn-rift to post-rift stratigraphy in order to predict the thermal history of the Vulcan Sub-basin.


Clay Minerals ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 407-419 ◽  
Author(s):  
J. Alonso-Azcarate ◽  
J. F. Barrenechea ◽  
M. Rodas ◽  
J. R. Mas

AbstractThe transition between very low-grade and low-grade metamorphism has been studied in the Urbión and Enciso Groups of the Late Jurassic-Early Cretaceous Cameros basin (NE Spain). The ‘illite crystallinity’ (IC) values do not appear to be controlled by burial depth but rather by: (1) XRD overlap with other phases (e.g. paragonite and mixed-layered muscovite-paragonite) in the siliciclastic samples; (2) the presence of carbonates, which delay illitization, resulting in an increase in the IC values, that becomes more pronounced as the P-T conditions decrease towards the diagenesis zone; and (3) the permeability of the sediments, which controls the circulation of metamorphic fluids and therefore the distribution of ‘crystallinities’ and mineral assemblages within the basin.The anchizone is represented by a narrow range of ‘chlorite crystallinity’ (ChC) values. Therefore, ChC is a less sensitive parameter than IC for estimating changes from diagenetic to low-grade metamorphic conditions. However, ChC can be a useful tool when there is a great heterogeneity of facies types, as it is not affected by the presence of carbonates.


1997 ◽  
Vol 17 (1) ◽  
pp. 363-387 ◽  
Author(s):  
W. Brian Harland ◽  
Simon R. A. Kelly

Jurassic-Cretaceous follows Triassic history with minor change. It was an interval dominated by deposition of marine muds, silts and sands, with occasional non-marine environments on advancing deltas (Parker 1967; Harland 1973a; Kelly 1988). Subdued topography contrasted with Triassic and Paleogene terrains. But there was also Late Jurassic and Early Cretaceous intrusion of basic sills and volcanism in eastern Svalbard. Figure 19.1 shows the distribution of Jurassic and Cretaceous deposits in Svalbard.The two periods (208-65 Ma) span 143 million years but the stratal record for this interval totals only 1700 m of which more than half was deposited in Albian time. The Jurassic-Cretaceous rocks of the eastern platform, presently cropping out on some islands, represent a relict of a once continuous sheet of strata, which is still preserved extensively across much of the Barents Shelf.The Triassic-Jurassic boundary is marked by seemingly continuous facies from Rhaetian to Toarcian; but then follows a contrast between the main Spitsbergen Basin (which hardly subsided) and the Eastern Platform. The contrasting areas of east and west Svalbard were divided by the continuing activity along the Billefjorden lineament. To the east, subsidence permitted a complex and variable sequence resulting from deltas from the east (marine and non-marine) through Liassic to mid-Bathonian time. To the west there was little evident subsidence and only condensed deposits of the uppermost Wilhelmoya Formation were washed by shallow seas. This part of the story concluded the history of the Kapp Toscana Group.A Late Bathonian marine transgression transformed east and


1985 ◽  
Vol 4 (1) ◽  
pp. 1-10 ◽  
Author(s):  
A. El-Arnauti ◽  
M. Shelmani

Abstract. INTRODUCTIONThe material which forms the basis of this project was obtained from a number of wells in the study area in Cyrenaica, the northeastern part of Libya. The study area, which is located between latitudes 25° and 33°N and between longitudes 20° and 25° E, covers some 365,750 square kilometres (see Fig. 1). The area extends from the Egyptian border in the east to the eastern flank of the Sirte Basin in the west and is part of the stable Saharan Shield.Since Precambrian time several phases of epeirogenic movements have produced troughs, horst blocks or platforms which have in turn influenced the subsequent sedimentological history of the area. In the southern and southeastern part of the study area, the basement is unconformably overlain by a thick, partially marine Palaeozoic sequence which is in turn unconformably overlain by sediments of Jurassic or younger age. The basement in the central and southwestern parts of the area is unconformably overlain by non-marine clastics of Late Jurassic and Early Cretaceous age or by marine sediments of Late Cretaceous and Tertiary age. In the eastern and northeastern section the basement is overlain by a wedge of eastward thickening marine Palaeozoic rocks which are in turn unconformably overlain by marine sediments of Late Cretaceous and Tertiary age. In the most northerly part of the northeastern region of the study area, a thick paralic sequence of Triassic, Jurassic and Early Cretaceous deposits is unconformably overlain by Late Cretaceous and Tertiary sediments.PALAEOZOICRocks of Cambro-Ordovician . . .


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