scholarly journals Petrological vestiges of the Late Jurassic-Early Cretaceous transition from rift to back-arc basin in southernmost Chile: New age and geochemical data from the Capit^|^aacute;n Aracena, Carlos III, and Tortuga ophiolitic complexes

2013 ◽  
Vol 47 (2) ◽  
pp. 201-217 ◽  
Author(s):  
M. CALDER^|^Oacute;N ◽  
C. F. PRADES ◽  
F. HERV^|^Eacute; ◽  
V. AVENDA^|^Ntilde;O ◽  
C. M. FANNING ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
New Age ◽  
Geochemical Data ◽  
Back Arc ◽  
Carlos Iii

THE PETROLEUM GEOCHEMISTRY OF OILS AND SOURCE ROCKS FROM THE NORTHERN BONAPARTE BASIN, OFFSHORE NORTHERN AUSTRALIA

2000 ◽  
Vol 40 (1) ◽  
pp. 257 ◽  
Author(s):  
J.C. Preston ◽  
D.S. Edwards
Keyword(s):  
Source Rock ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Structural Complexity ◽  
Source Rocks ◽  
Geochemical Data ◽  
Northwestern Part ◽  
Migration Patterns ◽  
Catchment Areas ◽  
Migration Pathways

Geochemical data from oils and source rock extracts have been used to delineate the active petroleum systems of the Northern Bonaparte Basin. The study area comprises the northeastern portion of the Territory of Ashmore and Cartier Islands, and the western part of the Zone of Co-operation Area A, and is specifically concerned with the wells located on and between the Laminaria and Flamingo highs. The oils and condensates from this region can be divided into two distinct chemical groups which correspond with the reservoir types, namely, a smaller group recovered from fracture porosity within the Early Cretaceous Darwin Formation, and a larger group reservoired in sandstones of the Middle-to-Late Jurassic Plover and Elang formations. The oils recovered from the Darwin Formation have a marine source affinity and correlate with sediment extracts from the underlying Early Cretaceous Echuca Shoals Formation. The Elang/ Plover-reservoired oils, which include all the commercial accumulations, were divided into two end-member families; the first includes the relatively land-plant- influenced oils from the northwestern part of the area (e.g. Laminaria, Corallina, Buffalo and Jahal fields), the second includes the relatively marine-influenced oils to the southeast (e.g. Bayu-Undan fields). Another oil family comprises the geographically and geochemically intermediate oils of the Elang and Kakatua fields and adjacent areas. While none of the oils can be uniquely correlated with a single source unit, they show geochemical similarities with Middle-to-Late Jurassic source rock extracts. Organic-rich rocks within the Plover and Elang formations are the major source of hydrocarbons for this area. The range in geochemistry of the Elang/Plover-reservoired oils may arise from facies variation within these sediments, but is more probably due to the localised additional input of hydrocarbons generated from thermally mature organic-rich claystone seals that overlie the Elang reservoir in catchment areas and traps; i.e. from the Frigate Formation for the northwestern oil family and from the Flamingo Group for the southeastern oil family. The short-range migration patterns dictated by the structural complexity of the basin are reflected in the closeness with which variations in the geochemical character of the accumulated liquids track variations in the character of source-seal lithologies. The length of migration pathways can, therefore, be inferred from the similarity or otherwise of source-seal characters with those of the hydrocarbon accumulations themselves. The resulting observations may challenge existing ideas concerning migration patterns, hydrocarbon prospectivity and prospect risking within the Northern Bonaparte Basin.

The newest structures of the Heraclion peninsula (South-Western Crimea)

2019 ◽  
pp. 8-16
Author(s):  
M. Yu. Promyslova ◽  
G. V. Bryantseva ◽  
L. I. Demina ◽  
N. I. Kosevich
Keyword(s):  
Oceanic Crust ◽  
Coastal Zone ◽  
Early Cretaceous ◽  
Late Jurassic ◽  
Fracture Zones ◽  
The South ◽  
South Eastern ◽  
Back Arc ◽  
Geomorphological Analysis

The article presents the results of the structural-geomorphological analysis of the Heraklion peninsula of the South-Western Crimea. The Western, Central and South-Eastern segments are distinguished, differing in density and direction of fracture zones, faults, the nature of the ravine-gulch net, and the structure of the coastal zone. It is shown that neotectonic movements in the upper structural floor are most intensively manifested over the Late Jurassic-Early Cretaceous collisional suture formed when the back-arc basin with the oceanic crust was closed.

Contrasting origins of late Mesozoic adakitic granitoids from the northwestern Jiaodong Peninsula, east China: implications for crustal thickening to delamination

2007 ◽  
Vol 144 (4) ◽  
pp. 619-631 ◽  
Author(s):  
MING-LAN HOU ◽  
YAO-HUI JIANG ◽  
SHAO-YONG JIANG ◽  
HONG-FEI LING ◽  
KUI-DONG ZHAO
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Early Stage ◽  
Eastern China ◽  
Alkali Feldspar ◽  
Crustal Thickening ◽  
Geochemical Data ◽  
Jiaodong Peninsula ◽  
T Values ◽  
Lower Crustal

Two suites of granitoids, the Late Jurassic (158 ± 3 Ma) Linglong suite and the Early Cretaceous (130–126 Ma) Guojialing suite, crop out in the northwestern Jiaodong Peninsula, eastern China. The Linglong suite is a monzogranite, comprising alkali feldspar, plagioclase, quartz and Fe-rich biotite. The Guojialing suite includes at least five plutonic bodies of both granodiorite and monzo-granite. The rocks are composed of plagioclase, alkali feldspar, quartz, Mg-rich amphibole and Mg-rich biotite. Both the Linglong and Guojialing suites have adakitic affinity. They are enriched in LREE with high La/Yb ratios and show positive Eu anomalies. The rocks are also enriched in LILE and depleted in HFSE with high Sr/Y ratios. The Linglong granite shows very uniform Sr–Nd isotopic compositions with initial 87Sr/86Sr ratios of 0.7119–0.7126 and εNd (T) values of −21.3 to −21.6, which are similar to those of the local Neoarchaean basement. The Guojialing suite has variable initial 87Sr/86Sr ratios (0.7108–0.7120) and εNd (T) values (−10.8 to −17.2), which are distinct both from those of the Neoarchaean basement and from those of the local enriched lithospheric mantle inferred from the coeval mafic dykes in the studied area. Detailed petrological and geochemical data indicate that the Linglong suite was derived by partial melting of Neoarchaean metamorphic lower-crustal rocks at depth of > 50 km with a eclogite residue, whereas the Guojialing suite was formed by the reaction of delaminated eclogitic crust-derived melt with the upwelling asthenospheric mantle. The petrogenesis of these two contrasting adakitic granitoids suggests intensive lower-crustal delamination during Early Cretaceous times, following a crustal thickening process from the late stage of the Early Jurassic to early stage of the Late Jurassic with crustal thickness of < 32 km to > 50 km, respectively.

Petrogenesis and tectonic implications of Late Jurassic – Early Cretaceous granitic magmatism in the Xing’an Block, Northeast China: geochronological, geochemical, and Hf isotopic evidence

2018 ◽  
Vol 55 (6) ◽  
pp. 571-588 ◽  
Author(s):  
Yue He ◽  
Zhong-Hua He ◽  
Wen-Chun Ge ◽  
Hao Yang ◽  
Zhi-Hui Wang ◽  
...  
Keyword(s):  
Partial Melting ◽  
Early Cretaceous ◽  
Northeast China ◽  
Late Jurassic ◽  
Granitic Rocks ◽  
Geochemical Data ◽  
Magma Source ◽  
Isotopic Evidence ◽  
Depleted Mantle ◽  
Microgranular Enclaves

This study presents new geochronological, whole-rock geochemical, and zircon Hf isotopic evidence for the age, petrogenesis, and source of Mesozoic granitic rocks of the Xing’an Block, Northeast China. This evidence reveals the Late Mesozoic tectonic evolution of the eastern section of the Central Asian Orogenic Belt. Laser-ablation inductively coupled plasma – mass spectrometryzircon U–Pb age data indicate that the syenogranite, monzogranite, and alkali feldspar granite units, as well as their associated diorite microgranular enclaves, were emplaced between 150–142 Ma, providing evidence of Late Jurassic to Early Cretaceous magmatic events within the Xing’an Block. The granites contain high concentrations of SiO2 (65.24%–75.73 wt.%) and K2O (3.94%–5.30 wt.%), low concentrations of MgO (0.10%–1.30 wt.%), and A/CNK values of 0.92–1.06. In addition, Hf isotopic analysis of zircons from the 150–142 Ma granites yields εHf(t) values of +4.54 to +12.16 and two-stage Hf model aged from 906 to 423 Ma, indicating that they formed from magmas generated by partial melting of a juvenile Neoproterozoic–Phanerozoic accreted crustal source. The basic magma source for the diorite microgranular enclaves most likely formed from partial melting of a depleted mantle that had been metasomatized by subduction-related fluids. Combining these new geochemical data with the geology of this region, Late Jurassic to Early Cretaceous magmatism in the Xing’an Block most likely occurred in an extensional environment associated with closure of the Mongol–Okhotsk Ocean.

scholarly journals Metamorphic history and geodynamic significance of the Early Cretaceous Sabzevar granulites (Sabzevar structural zone, NE Iran)

2011 ◽  
Vol 3 (1) ◽  
pp. 477-526
Author(s):  
M. Nasrabady ◽  
F. Rossetti ◽  
T. Theye ◽  
G. Vignaroli
Keyword(s):  
Subduction Zone ◽  
Early Cretaceous ◽  
Oceanic Lithosphere ◽  
Geochemical Data ◽  
Data Set ◽  
Metamorphic History ◽  
History Of ◽  
Back Arc ◽  
Temperature Path ◽  
Ne Iran

Abstract. The Iranian ophiolites are part of the vast orogenic suture zones that mark the Alpine-Himalayan convergence zone. Few petrological and geochronological data are available from these ophiolitic domains, hampering a full assessment of the timing and regimes of subduction zone metamorphism and orogenic construction in the region. This paper describes texture, geochemistry and the pressure-temperature path of the Early Cretaceous granulites that occur within the Tertiary Sabzevar suture zone of NE Iran. The geochemical data set document that the granulites are remnants of a MORB-type oceanic crust and thus of a (Early Cretaceous ?) back-arc basin formed in the upper plate of the Neotethyan subduction and thus interpreted as portions of a dismembered dynamothermal sole formed during oceanic subduction. The metamorphic history of the granulites suggests an anticlockwise pressure-temperature loop, compatible with burial in a hot subduction zone followed by cooling during exhumation. This is interpreted as the evidence of a nascent subduction zone formed at the expenses of hot and hence young oceanic lithosphere. These data point to diachronous and independent tectonic evolutions of the different ophiolitic domains of central Iran, for which a growing heterogeneity in the timing of metamorphic equilibration and of pressure-temperature paths can be expected with further investigations.

NEW AGE AND GEOCHEMICAL PERSPECTIVE ON LATE JURASSIC DIKE SWARMS OF THE SW MOJAVE

2016 ◽  
Author(s):  
Anne A. Fulton ◽  
◽  
Jade Star Lackey ◽  
Kyle R. McCarty ◽  
Juliet Ryan-Davis ◽  
...  
Keyword(s):  
Late Jurassic ◽  
New Age ◽  
Dike Swarms

AGE MODEL FOR LATE JURASSIC THROUGH EARLY CRETACEOUS USED IN THE GEOLOGIC TIMESCALE 2012/2016 REFERENCE SCALES

2018 ◽  
Author(s):  
James G. Ogg ◽  
◽  
Chunju Huang ◽  
Chunju Huang ◽  
Linda A. Hinnov ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Age Model

Theropod teeth from the basalmost Cretaceous of Anoual (Morocco) and their palaeobiogeographical significance

2009 ◽  
Vol 146 (4) ◽  
pp. 602-616 ◽  
Author(s):  
F. KNOLL ◽  
J. I. RUIZ-OMEÑACA
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Dispersal Events ◽  
Early Occurrence

AbstractThe theropod teeth from the Berriasian (Early Cretaceous) site of Anoual (N Morocco) are described. The assemblage is important in that it comes from one of the very few dinosaur sites of this age globally and the only one for the whole of Gondwana. The theropod teeth from Anoual are morphologically diverse. Most of the material possibly belongs to the clade Dromaeosauridae, which would be an early occurrence for this taxon. The palaeogeographic position of Anoual enables it to provide data on the dispersal events that affected terrestrial faunas during Mesozoic times. A Laurasian influence is evidenced by the presence of Velociraptorinae and, on the whole, the theropod fauna from Anoual provides support for the existence of a trans-Tethyan passage allowing terrestrial faunal interchanges during Late Jurassic and/or earliest Cretaceous times. Additionally, Anoual records the existence of diminutive theropods. However, it cannot yet be determined whether the small size of the specimens is genetic or ontogenetic.

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