A Low-Temperature Hydrothermal Maturation Mechanism for Sedimentary Basins Associated With Volcanic Rocks

Author(s):  
Neil S. Summer ◽  
Kenneth L. Verosub
Geofluids ◽  
2012 ◽  
Vol 12 (4) ◽  
pp. 295-311 ◽  
Author(s):  
M. KOUSEHLAR ◽  
T. B. WEISENBERGER ◽  
F. TUTTI ◽  
H. MIRNEJAD

1996 ◽  
Vol 33 (8) ◽  
pp. 1193-1200
Author(s):  
Pierre A. Cousineau ◽  
Robert Marquis

Structural analyses of folded volcano-sedimentary basins rely heavily on the identification and use of way-up structures. These structures are more numerous and widespread in sedimentary rocks than in volcanic rocks. Structural models for such basins can therefore be biased by this fact. The Caldwell Group of the Quebec Appalachians is a folded volcano-sedimentary basin bounded bay major faults. It contains locally abundant basalt-rich bands. Near Lac-Etchemin, way-up in basalt flows is determined by pillow shelves that reflect paleohorizontal planes. The strike and dip of these shelf structures were measured and plotted on stereographic projections. Field evidence and the interpretation of stereographic projections indicate that the basalt-rich bands form open folds that plunge gently to the southwest. However, sandstone-rich bands form tight folds with undulating hinge lines (sheath-like). During initial folding, the basalt formed competent bands with limited aerial extent that were fractured by synthetic and antithetic faults rather than folded. The basalt slivers maintained a near-horizontal attitude while adjacent sedimentary rocks were folded and faulted. Further shortening tightened folds in the sediment-rich bands while producing open folds in slivers of basaltic rocks.


2021 ◽  
Author(s):  
Jennifer Spalding ◽  
Jeremy Powell ◽  
David Schneider ◽  
Karen Fallas

<p>Resolving the thermal history of sedimentary basins through geological time is essential when evaluating the maturity of source rocks within petroleum systems. Traditional methods used to estimate maximum burial temperatures in prospective sedimentary basin such as and vitrinite reflectance (%Ro) are unable to constrain the timing and duration of thermal events. In comparison, low-temperature thermochronology methods, such as apatite fission track thermochronology (AFT), can resolve detailed thermal histories within a temperature range corresponding to oil and gas generation. In the Peel Plateau of the Northwest Territories, Canada, Phanerozoic sedimentary strata exhibit oil-stained outcrops, gas seeps, and bitumen occurrences. Presently, the timing of hydrocarbon maturation events are poorly constrained, as a regional unconformity at the base of Cretaceous foreland basin strata indicates that underlying Devonian source rocks may have undergone a burial and unroofing event prior to the Cretaceous. Published organic thermal maturity values from wells within the study area range from 1.59 and 2.46 %Ro for Devonian strata and 0.54 and 1.83 %Ro within Lower Cretaceous strata. Herein, we have resolved the thermal history of the Peel Plateau through multi-kinetic AFT thermochronology. Three samples from Upper Devonian, Lower Cretaceous and Upper Cretaceous strata have pooled AFT ages of 61.0 ± 5.1 Ma, 59.5 ± 5.2 and 101.6 ± 6.7 Ma, respectively, and corresponding U-Pb ages of 497.4 ± 17.5 Ma (MSWD: 7.4), 353.5 ± 13.5 Ma (MSWD: 3.1) and 261.2 ± 8.5 Ma (MSWD: 5.9). All AFT data fail the χ<sup>2</sup> test, suggesting AFT ages do not comprise a single statistically significant population, whereas U-Pb ages reflect the pre-depositional history of the samples and are likely from various provenances. Apatite chemistry is known to control the temperature and rates at which fission tracks undergo thermal annealing. The r<sub>mro</sub> parameter uses grain specific chemistry to predict apatite’s kinetic behaviour and is used to identify kinetic populations within samples. Grain chemistry was measured via electron microprobe analysis to derive r<sub>mro</sub> values and each sample was separated into two kinetic populations that pass the χ<sup>2</sup> test: a less retentive population with ages ranging from 49.3 ± 9.3 Ma to 36.4 ± 4.7 Ma, and a more retentive population with ages ranging from 157.7 ± 19 Ma to 103.3 ± 11.8 Ma, with r<sub>mr0</sub> benchmarks ranging from 0.79 and 0.82. Thermal history models reveal Devonian strata reached maximum burial temperatures (~165°C-185°C) prior to late Paleozoic to Mesozoic unroofing, and reheated to lower temperatures (~75°C-110°C) in the Late Cretaceous to Paleogene. Both Cretaceous samples record maximum burial temperatures (75°C-95°C) also during the Late Cretaceous to Paleogene. These new data indicate that Devonian source rocks matured prior to deposition of Cretaceous strata and that subsequent burial and heating during the Cretaceous to Paleogene was limited to the low-temperature threshold of the oil window. Integrating multi-kinetic AFT data with traditional methods in petroleum geosciences can help unravel complex thermal histories of sedimentary basins. Applying these methods elsewhere can improve the characterisation of petroleum systems.</p>


2021 ◽  
Author(s):  
Sabrina Kainz ◽  
Lon Abbott ◽  
Rebecca Flowers ◽  
James Metcalf

<p>Past work has used the Southern Rocky Mountains (SRM) in the U.S. state of Colorado to illustrate the important role that rock strength plays in the histories recorded by the apatite fission track (AFT) and apatite (U-Th)/He (AHe) low-temperature thermochronometers (Flowers & Ehlers, 2018). The SRM were initially raised during the Laramide Orogeny, ca. 70-45 Ma, but consensus exists that the region also experienced a later, post-Laramide exhumation event. Flowers & Ehlers (2018) pointed to the low erosion potential of the Precambrian crystalline basement rocks that crop out in most SRM ranges as a primary reason for the abundance of 55-70 Ma “Laramide” AFT and AHe dates in the region, compared to a paucity of younger dates that would presumably be produced through erosion triggered by the post-Laramide exhumation event. South-central Colorado offers a test of this hypothesis, due to lateral variations in rock erodibility provided by the presence here of both sedimentary and crystalline Laramide ranges and adjacent sedimentary basins. The combination of our ongoing AHe study with previous south-central Colorado AFT and AHe work reveals kilometer-scale post-Laramide (Oligo-Miocene) exhumation has occurred in areas that possess thick sedimentary rock sequences whereas exhumation has been negligible where crystalline basement comprises the land surface. </p><p>South-central Colorado’s Sangre de Cristo Mountains consist of an imbricate stack of thrust sheets composed of Permian sedimentary rock. About 30 km farther east stand the Wet Mountains, another Laramide range – but one composed of Precambrian basement rock. The Raton Basin, a SRM foreland basin filled with 2 km of synorogenic fill underlain by a thick sequence of marine shale, lies south and east of the two ranges. The Wet Mountains thus form a peninsula of strong crystalline rock surrounded by more erodible sedimentary rocks to the west, south, and east. </p><p>Our study and that of Landman (2018) records at least 2 km of erosion in the Raton Basin east and south of the Wet Mountains since 25 Ma. Lindsey et al (1986) obtained 24-15 Ma AFT dates from the Paleozoic sedimentary rocks of the Sangre de Cristo Mountains, demonstrating that kilometer-scale Oligo-Miocene exhumation occurred just west of the Wet Mountains. By contrast, Kelley and Chapin (2004) obtained only pre-Laramide AFT ages between 228-110 Ma for 17 samples of Precambrian basement from the crest of the Wet Mountains. A 32 Ma ash flow tuff unconformably overlies Precambrian basement on Greenhorn Mountain, the Wet Mountains’ highest and southernmost peak. Its presence reinforces the conclusion, based on the AFT dates, that Oligo-Miocene erosion of the Wet Mountain massif has been minimal simultaneous with kilometer-scale exhumation to the west, south, and east. These results illustrate the important role that rock strength plays in determining the dates recorded in low-temperature thermochronologic studies.</p>


2014 ◽  
Vol 53 ◽  
pp. 71-87 ◽  
Author(s):  
Thomas Blaise ◽  
Jocelyn Barbarand ◽  
Myriam Kars ◽  
Florian Ploquin ◽  
Charles Aubourg ◽  
...  

2018 ◽  
Vol 55 (8) ◽  
pp. 905-922 ◽  
Author(s):  
Pierre Bedeaux ◽  
Lucie Mathieu ◽  
Pierre Pilote ◽  
Silvain Rafini ◽  
Réal Daigneault

The Piché Structural Complex (PSC) extends over 150 km within the Cadillac – Larder Lake Fault Zone (CLLFZ), a gold-endowed, east-trending, and high-strain corridor located along the southern edge of the Archean Abitibi Subprovince. The PSC consists of discontinuous units of volcanic rocks (<1 km thick) that host multiple gold deposits. It is spatially associated with molasse-type Timiskaming sedimentary basins. This study describes and interprets the origin of structures and lithologies within the poorly understood PSC to unravel the tectonic evolution of the CLLFZ. Field mapping, chemical analyses, as well as interpretations of cross-sections from drill-hole data, were used to interpret the geometry and structure of the PSC. The PSC is subdivided into six homogeneous fault-bounded segments or slivers. These slivers consist mostly of ultramafic to intermediate volcanic rocks and include some felsic volcanic flows and intrusions. Volcanic facies, chemical compositions, and isotopic ages confirm that these slivers are derived from the early volcanic units of the southern Abitibi greenstone belt, which are located north of the CLLFZ. Cross-cutting relationships between volcanic rocks of the PSC and the Timiskaming-aged intrusions suggest that the slivers were inserted into the CLLFZ during the early stages of the accretion-related deformation (<2686 Ma) and prior to Timiskaming sedimentation and ductile deformation (>2676 Ma). The abundant ultramafic rocks located within the CLLFZ may have focused strain, thereby facilitating the nucleation of the fault as well as the displacements along this crustal-scale structure.


Author(s):  
P.I. Fedorov ◽  
◽  
N.V. Tsukanov ◽  
A.R. Geptner ◽  
V.V. Petrova ◽  
...  

The article presents new petrogeochemical data on the Middle Miocene-Pliocene volcanic rocks from central part of Iturup Island (Great Kurile Chain). It is shown that volcanism of the Middle Miocene-Early Pliocene age in the central part of the Iturup Island took place in a suprasubduction setting. The distribution of high field strength elements (HFSE) and their ratio in the basaltoids indicate their formation upon partial melting of the depleted upper mantle, while the enrichment of rocks with large ionic lithophilic elements (LILE) indicates both a fluid mantle additive introduced into the melts during the evolution of primary magma and the participation of a low-temperature suprasubduction fluid. The established differences in the composition of the basaltoids of the frontal and rear zones due to the limited number of analyzed samples are considered preliminary. Thus, basaltoids in the rear zone are distinguished by higher concentrations of Th, Pb, HFSE (Nb, Zr, Y, Hf), relative enrichment in LREE, pronounced negative Zr and Hf anomalies, and positive Eu.


2002 ◽  
Vol 66 (3) ◽  
pp. 379-384 ◽  
Author(s):  
D. K. Bailey ◽  
S. Kearns

AbstractMagnetite is present in most carbonatites, and in the most abundant and best-known form of carbonatite, coarse-grained intrusions, it typically falls in a narrow composition range close to Fe3O4. A fine-grained carbonatite from Zambia contains magnetites with an extraordinary array of compositions (from 18–1% TiO2, 10–2% Al2O3, and 16–4% MgO) outranging previously-reported examples. Zoning trends are from high TiO2 to high Al2O3 and MgO. No signs of exsolution are seen. Checks on similar rocks from Germany, Uganda and Tanzania reveal magnetites with comparable compositions, ranges, and zoning. Magnetites from alkaline and alkaline ultramafic silicate volcanic rocks cover only parts of this array. Magnetite analyses from some other fine-grained carbonatites, reported in the literature, fall in the same composition field, suggesting that this form of carbonatite may be distinctive. The chemistry and zoning would be consonant with rapid high-temperature crystallization in the carbonatite melts, with the lack of exsolution pointing to fast quenching: this contrasts with coarse-grained intrusive carbonatites, in which the magnetite compositions are attributed to slow cooling, with final equilibration at low temperature. In some complexes, both forms of carbonatite, with their different magnetite compositions, are represented.


1978 ◽  
Vol 15 (1) ◽  
pp. 69-77 ◽  
Author(s):  
L. J. Ferguson ◽  
A. D. Edgar

The Crowsnest Formation consists of trachytes, analcime phonolites and blairmorites, metamorphosed to zeolite facies. The latter rocks contain large analcime phenocrysts variously suggested as being of primary igneous origin or due to transformation from original leucite by reaction of Na-rich fluids. Although neither field relationships or petrography provide convincing data favouring either hypothesis, the presence of primary undisrupted inclusion trails in the analcime tend to support the former hypothesis. Compositions of the analcimes differ from that of an analcime formed by transformation from leucite. The chemistry of the rocks and their constituent pyroxenes are consistent with a sodic rather than a potassic differentiation trend; feldspar and garnet analyses support this conclusion. Oxygen isotope values for the pyroxenes indicate no extensive exchange with a low temperature fluid. Thus it seems unlikely that leucite was ever a constituent of the Crowsnest suite as necessitated by the hypothesis of transformation from leucite. Geochemistry and known experimental data indicate that the analcime phonolites and blairmorites differentiated from a trachytic magma under restricted conditions at depths greater than 25 km by early sanidine and later analcime fractionation. The parental trachyte may be produced by partial fusion of crustal material at depths greater than 35 km.


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