A NEW PLAY IN THE GIPPSLAND BASIN

1987 ◽  
Vol 27 (1) ◽  
pp. 164 ◽  
Author(s):  
David C. Lowry
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Before Present ◽  
Angular Unconformity ◽  
Seismic Sections ◽  
Gippsland Basin

Explorers of the Cippsland Basin have generally assumed that the prospective Latrobe Group (Late Cretaceous to Eocene) is separated from the Strzelecki Group (Early Cretaceous) by an angular unconformity dated at about 100 million years before present (Ma). Thus all sub-unconformity traps seen on seismic sections have been assumed to be developed in the unprospective Strzelecki Group. Evidence from seismic sections and wells indicates that this unconformity should be dated at about 80 Ma. The beds deposited between 80 and 100 Ma are part of the Late Cretaceous Latrobe Group and have the potential for both reservoirs and intraformational seals.This new sub-unconformity play can be pursued in areas transitional between the Central Deep and the flanking platforms. On the platforms the prospective beds are absent because of truncation while in the Central Deep they are beyond the reach of the drill.

A NEW MODEL FOR THE MID-CRETACEOUS STRUCTURAL HISTORY OF THE NORTHERN GIPPSLAND BASIN

1991 ◽  
Vol 31 (1) ◽  
pp. 143 ◽  
Author(s):  
D.C. Lowry ◽  
I.M. Longley
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Second Phase ◽  
Northern Flank ◽  
Tectonic History ◽  
Structural History ◽  
Intermittent Compression ◽  
History Of ◽  
Transfer Faults ◽  
Gippsland Basin

The tectonic history of the northern flank of the offshore Gippsland Basin can be divided into three phases:an Early Cretaceous rift phase (120-98 Ma) with deposition of the Strzelecki Group and extension in a northeast-southwest direction.a mid-Cretaceous phase (98-80 Ma) with deposition of the Golden Beach Group and extension in a northwest- southeast direction anda Late Cretaceous to Tertiary sag phase with intermittent compression or wrenching.Previous workers have described the first and third phases. This paper argues for a distinctive second phase with extension at right angles to the first phase. The complex Cretaceous structure in the Kipper-Hammerhead area is interpreted in terms of a model in which transfer faults of the first phase became domino faults of the second phase.

scholarly journals Quantitative strain analysis of strike-slip displacements across the Arne-Elin trend, the Danish Central Graben

1996 ◽  
Vol 43 ◽  
pp. 99-113
Author(s):  
Ole Rønø Clausen ◽  
John A. Korstgård ◽  
Tommy Mogensen Egebjerg
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Strain Analysis ◽  
Fault System ◽  
Stress System ◽  
Fault Systems ◽  
Seismic Sections ◽  
The Individual ◽  
Zechstein Salt ◽  
Flower Structures

A method is presented for unravelling the displacement history across transpressionand transtension zones recognized on seismic sections as flower structures. The method has been applied to the Arne-Elin trend in the northern part of the Danish Central Graben. The results suggest sinistral movement with alternating transpression and transtension along strike during the Early Cretaceous, and dextral transpressive movement during the Late Cretaceous and Paleogene. However, there is considerable variation in displacement along strike of the zone during the individual periods. The variation in displacement along the strike of the Arne-Elin trend is accommodated by displacement along the fault systems in the adjoining areas. The displacement along fault systems in the adjoining areas was sinistral during the Early Cretaceous and dextral during the post-Early Cretaceous, similar to the movement along the Arne-Elin trend during the two periods. The analysis gives a detailed picture of the movements along the general structural trend and emphasizes the differences between the two periods. One of the most marked differences is that the fault system separating the Gertrud Graben, the Feda Graben and the Heno Plateau becomes locked during the Late Cretaceous/Paleogene while the Arne-Elin trend is strongly inverted. Observations show that the major inversion structures are often underlain by Zechstein salt. Contemporaneous normal faulting (local extension), however, took place without involvement of salt. The onset of inversion of previously generated structures therefore depended not only on changes in the regional stress system, but also seems to be controlled by the rheology of the rocks involved.

A regional seismic synthesis of the offshore Gippsland Basin

1989 ◽  
Vol 20 (2) ◽  
pp. 313
Author(s):  
T.U. Maung
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Tectonic Regime ◽  
Contour Maps ◽  
Tectonic Events ◽  
Formation And Evolution ◽  
Gippsland Basin

Structure contour maps compiled and synthesised from interpretive company data for top of Strzelecki Group/Basement, intra-Latrobe Group, and top of Latrobe Group seismic horizons give an indication of the formation and evolution of the Gippsland Basin during Early Cretaceous, and Late Cretaceous to Tertiary tectonic events. Comparison of the intra- and top of Latrobe Group mapping illustrates a change from a largely extensional to a compressive tectonic regime during the Eocene.

Ginkgophytes of the Ul’ya flora (the Ul’ya depresiion, the Okhotsk-Chukotka volcanogenic belt)

Palaeobotany ◽  
2016 ◽  
Vol 7 ◽  
pp. 80-95 ◽  
Author(s):  
L. B. Golovneva
Keyword(s):  
New Species ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Middle Part ◽  
Leaf Length ◽  
Volcanogenic Belt ◽  
Short Shoots ◽  
Volcanogenic Deposits

The Ul’ya flora comes from the Coniacian volcanogenic deposits of the Amka Formation (the Ul'ya depression, southern part of the Okhotsk-Chukotka volcanogenic belt). Ginkgoaleans are diverse in this flora and represented by three genera: Ginkgo, Sphenobaiera and Baiera. All specimens have no cuticle and were assigned to morphotaxa. Genus Ginkgo includes two species: G. ex gr. adiantoides (Ung.) Heer with entire leaves and G. ex gr. sibirica Heer with dissected leaves. Genus Sphenobaiera also consists of two species: S. ex gr. longifolia (Pom.) Florin with 4–8 leaf lobes and S. ex gr. biloba Prynada with two leaf lobes. Genus Baiera is represented by new species B. lebedevii Golovn., sp. nov.Leaves of this species are 25–30 cm long and 13–16 cm wide, narrowly wedge-shaped with flat slender petiole, dichotomously dissected 4–5 times into linear segments 3–6 mm wide with 6–12 veins. The length of ultimate segments is equal to about a half of leaf length. Leaves attached spirally to ovoid short shoots about 2 cm long. Among the Late Cretaceous floras similar diversity of ginkgoaleans was recorded only in the Turonian-Coniacian Arman flora from middle part of the Okhotsk-Chukotka volcanogenic belt (Herman et al., 2016). Four species of ginkgoaleans from the Ul’ya flora (except G. ex gr. adiantoides) are considered as the Early Cretaceous relicts.

scholarly journals Burial and Exhumation History of the Lujing Uranium Ore Field, Zhuguangshan Complex, South China: Evidence from Low-Temperature Thermochronology

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 116
Author(s):  
Yue Sun ◽  
Barry P. Kohn ◽  
Samuel C. Boone ◽  
Dongsheng Wang ◽  
Kaixing Wang
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
South China ◽  
Thermal History ◽  
Fission Track ◽  
Thermal Evolution ◽  
Negative Relationship ◽  
The Tibetan Plateau ◽  
Uranium Ore ◽  
Production Area

The Zhuguangshan complex hosts the main uranium production area in South China. We report (U-Th)/He and fission track thermochronological data from Triassic–Jurassic mineralized and non-mineralized granites and overlying Cambrian and Cretaceous sandstone units from the Lujing uranium ore field (LUOF) to constrain the upper crustal tectono-thermal evolution of the central Zhuguangshan complex. Two Cambrian sandstones yield reproducible zircon (U-Th)/He (ZHe) ages of 133–106 Ma and low effective uranium (eU) content (270–776 ppm). One Upper Cretaceous sandstone and seven Mesozoic granites are characterized by significant variability in ZHe ages (154–83 Ma and 167–36 Ma, respectively), which show a negative relationship with eU content (244–1098 ppm and 402–4615 ppm), suggesting that the observed age dispersion can be attributed to the effect of radiation damage accumulation on 4He diffusion. Correspondence between ZHe ages from sandstones and granites indicates that surrounding sedimentary rocks and igneous intrusions supplied sediment to the Cretaceous–Paleogene Fengzhou Basin lying adjacent to the LUOF. The concordance of apatite fission track (AFT) central ages (61–54 Ma) and unimodal distributions of confined track lengths of five samples from different rock units suggest that both sandstone and granite samples experienced a similar cooling history throughout the entire apatite partial annealing zone (~110–60 °C). Apatite (U-Th-Sm)/He (AHe) ages from six non-mineralized samples range from 67 to 19 Ma, with no apparent correlation to eU content (2–78 ppm). Thermal history modeling of data suggests that the LUOF experienced relatively rapid Early Cretaceous cooling. In most samples, this was followed by the latest Early Cretaceous–Late Cretaceous reheating and subsequent latest Late Cretaceous–Recent cooling to surface temperatures. This history is considered as a response to the transmission of far-field stresses, involving alternating periods of regional compression and extension, related to paleo-Pacific plate subduction and subsequent rollback followed by Late Paleogene–Recent India–Asia collision and associated uplift and eastward extrusion of the Tibetan Plateau. Thermal history models are consistent with the Fengzhou Basin having been significantly more extensive in the Late Cretaceous–Early Paleogene, covering much of the LUOF. Uranium ore bodies which may have formed prior to the Late Cretaceous may have been eroded by as much as ~1.2 to 4.8 km during the latest Late Cretaceous–Recent denudation.

scholarly journals Discovery of Lebambromyia in Myanmar Cretaceous Amber: Phylogenetic and Biogeographic Implications (Insecta, Diptera, Phoroidea)

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 354
Author(s):  
Davide Badano ◽  
Qingqing Zhang ◽  
Michela Fratini ◽  
Laura Maugeri ◽  
Inna Bukreeva ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Phase Contrast ◽  
First Record ◽  
Geographic Range ◽  
X Ray ◽  
Monophyletic Lineage ◽  
Cladistic Analyses

Lebambromyia sacculifera sp. nov. is described from Late Cretaceous amber from Myanmar, integrating traditional observation techniques and X-ray phase contrast microtomography. Lebambromyia sacculifera is the second species of Lebambromyia after L. acrai Grimaldi and Cumming, described from Lebanese amber (Early Cretaceous), and the first record of this taxon from Myanmar amber, considerably extending the temporal and geographic range of this genus. The new specimen bears a previously undetected set of phylogenetically relevant characters such as a postpedicel sacculus and a prominent clypeus, which are shared with Ironomyiidae and Eumuscomorpha. Our cladistic analyses confirmed that Lebambromyia represented a distinct monophyletic lineage related to Platypezidae and Ironomyiidae, though its affinities are strongly influenced by the interpretation and coding of the enigmatic set of features characterizing these fossil flies.

scholarly journals Polyphase evolution of Pelagonia (northern Greece) revealed by geological and fission-track data

Solid Earth ◽  
2015 ◽  
Vol 6 (1) ◽  
pp. 285-302 ◽  
Author(s):  
F. L. Schenker ◽  
M. G. Fellin ◽  
J.-P. Burg
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Fission Track ◽  
Regional Scale ◽  
Normal Faults ◽  
Recent Sediment ◽  
Northern Greece ◽  
Rapid Cooling ◽  
Fission Track Ages ◽  
Pelagonian Zone

Abstract. The Pelagonian zone, situated between the External Hellenides/Cyclades to the west and the Axios/Vardar/Almopias zone (AVAZ) and the Rhodope to the east, was involved in late Early Cretaceous and in Late Cretaceous–Eocene orogenic events whose duration and extent are still controversial. This paper constrains their late thermal imprints. New and previously published zircon (ZFT) and apatite (AFT) fission-track ages show cooling below 240 °C of the metamorphic western AVAZ imbricates between 102 and 93–90 Ma, of northern Pelagonia between 86 and 68 Ma, of the eastern AVAZ at 80 Ma and of the western Rhodope at 72 Ma. At the regional scale, this heterogeneous cooling is coeval with subsidence of Late Cretaceous marine basin(s) that unconformably covered the Early Cretaceous (130–110 Ma) thrust system from 100 Ma. Thrusting resumed at 70 Ma in the AVAZ and migrated across Pelagonia to reach the External Hellenides at 40–38 Ma. Renewed thrusting in Pelagonia is attested at 68 Ma by abrupt and rapid cooling below 240 °C and erosion of the gneissic rocks. ZFT and AFT in western and eastern Pelagonia, respectively, testify at ~40 Ma to the latest thermal imprint related to thrusting. Central-eastern Pelagonia cooled rapidly and uniformly from 240 to 80 °C between 24 and 16 Ma in the footwall of a major extensional fault. Extension started even earlier, at ~33 Ma in the western AVAZ. Post-7 Ma rapid cooling is inferred from inverse modeling of AFT lengths. It occurred while E–W normal faults were cutting Pliocene-to-recent sediment.

Mesozoic Tectonic Setting of SE Sundaland After Magmatism and Suture Evidences in JS-1 Ridge Area

2021 ◽  
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Tectonic Setting ◽  
Plate Boundary ◽  
Early Jurassic ◽  
The South ◽  
Magmatic Arc ◽  
Plate Convergence ◽  
Ridge Area ◽  
Cretaceous Subduction

Mesozoic plate convergence in SE Sundaland has been a source of debate for decades. A determination of plate convergence boundaries and timing have been explained in many publications, but not all boundaries were associated with magmatism. Through integration of both plate configurations and magmatic deposits, the basement can be accurately characterized over time and areal extents. This paper will discuss Cretaceous subductions and magmatic arc trends in SE Sundaland area with additional evidence found in JS-1 Ridge. At least three subduction trends are captured during the Mesozoic in the study area: 1) Early Jurassic – Early Cretaceous trend of Meratus, 2) Early Cretaceous trend of Bantimala and 3) Late Cretaceous trend in the southernmost study area. The Early Jurassic – Early Cretaceous subduction occurred along the South and East boundary of Sundaland (SW Borneo terrane) and passes through the Meratus area. The Early Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo and Paternoster terranes) and pass through the Bantimala area. The Late Cretaceous subduction occurred along South and East boundary of Sundaland (SW Borneo, Paternoster and SE Java – South Sulawesi terranes), but is slightly shifted to the South approaching the Oligocene – Recent subduction zone. Magmatic arc trends can also be generally grouped into three periods, with each period corresponds to the subduction processes at the time. The first magmatic arc (Early Jurassic – Early Cretaceous) is present in core of SW Borneo terrane and partly produces the Schwaner Magmatism. The second Cretaceous magmatic arc (Early Cretaceous) trend is present in the SW Borneo terrane but is slightly shifted southeastward It is responsible for magmatism in North Java offshore, northern JS-1 Ridge and Meratus areas. The third magmatic arc trend is formed by Late Cretaceous volcanic rocks in Luk Ulo, the southern JS-1 Ridge and the eastern Makassar Strait areas. These all occur during the same time within the Cretaceous magmatic arc. Though a mélange rock sample has not been found in JS-1 Ridge area, there is evidence of an accretionary prism in the area as evidenced by the geometry observed on a new 3D seismic dataset. Based on the structural trend of Meratus (NNE-SSW) coupled with the regional plate boundary understanding, this suggests that both Meratus & JS-1 Ridge are part of the same suture zone between SW Borneo and Paternoster terranes. The gradual age transition observed in the JS-1 Ridge area suggests a southward shift of the magmatic arc during Early Cretaceous to Late Cretaceous times.

Interplay between tectonic inheritance and salt tectonics in the tectono-sedimentary evolution of the Sahel basin (eastern Tunisia): implications for hydrocarbon prospectivity

2021 ◽  
Author(s):  
Wajdi Belkhiria ◽  
Haifa Boussiga ◽  
Imen Hamdi Nasr ◽  
Adnen Amiri ◽  
Mohamed Hédi Inoubli
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Gravity Data ◽  
Hydrocarbon Exploration ◽  
Passive Margin ◽  
Growth Strata ◽  
Tectonic Inheritance ◽  
Sedimentary Evolution ◽  
Structural Style ◽  
Half Graben

<p>The Sahel basin in eastern Tunisia has been subject for hydrocarbon exploration since the early fifties. Despite the presence of a working petroleum system in the area, most of the drilled wells were dry or encountered oil shows that failed to give commercial flow rates. A better understanding of the tectono-sedimentary evolution of the Sahel basin is of great importance for future hydrocarbon prospectivity. In this contribution, we present integration of 2D seismic reflection profiles, exploration wells and new acquired gravity data. These subsurface data reveal that the Sahel basin developed as a passive margin during Jurassic-Early Cretaceous times and was later inverted during the Cenozoic Alpine orogeny. The occurrence of Triassic age evaporites and shales deposited during the Pangea breakup played a fundamental role in the structural style and tectono-sedimentary evolution of the study area. Seismic and gravity data revealed jointly important deep-seated extensional faults, almost along E-W and few along NNE–SSW and NW-SE directions, delimiting horsts and grabens structures. These syn-rift extensional faults controlled deposition, facies distribution and thicknesses of the Jurassic and Early cretaceous series. Most of these inherited deep-seated normal and transform faults are ornamented by different types of salt-related structures. The first phase of salt rising was initiated mainly along these syn-extensional faults in the Late Jurassic forming salt domes and continued into the Early and Late Cretaceous leading to salt-related diapir structures. During this period, the salt diapirism was accompanied by the development of salt withdrawal minibasins, characterized important growth strata due the differential subsidence. These areas represent important immediate kitchen areas to the salt-related structures. The later Late Cretaceous - Cenozoic shortening phases induced preferential rejuvenation of the diapiric structures and led to the inversion of former graben/half-graben structures and ultimately to vertical salt welds along salt ridges. These salt structures represent key elements that remains largely undrilled in the Sahel basin. Our results improve the understanding of salt growth in eastern Tunisia and consequently greatly impact the hydrocarbon prospectivity in the area.</p>

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