Post-Palaeozoic cooling and uplift of the Brabant Massif as revealed by apatite fission track analysis

1993 ◽  
Vol 130 (5) ◽  
pp. 639-646 ◽  
Author(s):  
C. Vercoutere ◽  
P. Van Den Haute
Keyword(s):  
Fission Track ◽  
Track Length ◽  
Apatite Fission Track ◽  
Ambient Temperatures ◽  
The North ◽  
Projected Length ◽  
The North Sea ◽  
Cooling Phase ◽  
Fission Track Ages ◽  
Length Analysis

AbstractA fission track study has been carried out on apatite from the igneous rock belt running along the southern border of the Brabant Massif. The study includes age determinations and a length analysis of both surface tracks and confined tracks. Apatite fission track ages vary between 146 Ma and 209 Ma. Confined track length distributions and the projected length age spectra indicate that the rocks cooled relatively rapidly from above 100 °C to ambient temperatures. The fission track ages therefore date a cooling phase of the Brabant Massif which is interpreted as reflecting an important uplift during the major part of the Jurassic, related to the Cimmerian tectonism which affected the North Sea basin and adjacent areas. Two apatite samples from the southerly Dinant Basin yield fission track ages around 200 Ma, similar to the oldest ages observed in the Brabant Massif, and with comparable track length characteristics. This indicates that the uplift was not limited to the Brabant region but also affected the Hercynian basement to the south.

Thermochronologic constraints on ore formation at the Gays River Pb–Zn deposit, Nova Scotia, Canada, from apatite fission track analysis

1990 ◽  
Vol 27 (8) ◽  
pp. 1013-1022 ◽  
Author(s):  
Dennis C. Arne ◽  
Ian R. Duddy ◽  
Don F. Sangster
Keyword(s):  
Nova Scotia ◽  
Fission Track ◽  
Track Length ◽  
Late Paleozoic ◽  
Apatite Fission Track ◽  
Ore Formation ◽  
Sulphide Mineralization ◽  
Fission Track Ages ◽  
Uplift And Erosion ◽  
Host Rocks

Fission tracks in detrital apatites from the Cambro-Ordovician metasedimentary basement in the vicinity of the Carboniferous-hosted Gays River Pb–Zn deposit, Nova Scotia, provide a record of final cooling during uplift and erosion of the Meguma Zone and constrain the timing of ore formation. Apatite fission track ages range from 203 to 241 Ma, with typical uncertainties of ± 10 Ma. Mean confined track lengths generally vary between 12.0 and 13.4 μm and indicate that the apatites record "apparent" ages only. An inferred thermal history involving regional heating to paleotemperatures > 110 °C during late Paleozoic burial followed by cooling to ~ 110 °C prior to 240–220 Ma is suggested. A more recent phase or regional heating to paleotem-peratures probably in the range of 60–80 °C during Late Cretaceous – early Tertiary (ca. 100–50 Ma) burial is also indicated by the track length data. Apatite fission track ages and mean track lengths from drill-core samples immediately beneath the Gays River orebody are similar to those for regional outcrop samples. At minimum temperatures > 200 °C estimated for ore formation, sulphide mineralization must either have preceded or accompanied regional heating to paleotemperatures > 110 °C during the late Paleozoic. Sulphide mineralization at Gays River must therefore have taken place at some time after ca. 330 Ma (the stratigraphic age of the lower Windsor Group host rocks) but before ca. 240–220 Ma (the last cooling of Meguma Group basement below 110 °C). These constraints on the timing of ore formation at Gays River are compatible with previous suggestions that Pb–Zn mineralization of Carboniferous strata in Nova Scotia occurred at ca. 300 Ma.

scholarly journals Thermo-tectonic studies of Mesozoic basement rocks, North Island, New Zealand

2021 ◽  
Author(s):  
◽  
Ruohong Jiao
Keyword(s):  
New Zealand ◽  
Fission Track ◽  
Late Oligocene ◽  
Apatite Fission Track ◽  
Exhumation Rate ◽  
The North ◽  
Basement Rocks ◽  
Thermal Histories ◽  
Fission Track Ages

<p>The basement rocks of North Island, New Zealand, comprise metasedimentary terranes that were accreted onto the eastern Gondwana margin during Mesozoic subduction. Since the Oligocene, these terranes have been sitting at the leading edge of the Australian Plate, as the hanging wall of the Hikurangi subduction margin, overriding the subducting Pacific Plate. This thesis examines the thermo-tectonic histories of the basement rocks in North Island, using fission-track and (U-Th-Sm)/He thermochronology.  In eastern North Island, thermochronological data from the basement rocks record the exhumation histories since the latest Jurassic, related to two subduction cycles. Zircon fission-track analysis yields detrital or slightly reset ages (264–102 Ma); apatite fission-track ages range from 122 to 7.9 Ma and (U-Th-Sm)/He from 33.3 to 6.0 Ma.  In central North Island, modelled thermal histories suggest that the basement rocks were exhumed to shallow levels (<2 km) of the crust in the Early Cretaceous (~150–135 Ma). This was followed by a period of reheating until ~100 Ma, which is interpreted to be the result of burial by sedimentation above the accretionary wedge. From 100 Ma, models indicate thermo-tectonic quiescence until the Late Oligocene.  During the late Cenozoic, exhumation of the basement rocks accelerated at ~27 Ma in the western margin of the axial ranges (Kaimanawa Mountains). This acceleration in exhumation rate is interpreted to reflect the initiation of the subduction of the Pacific Plate beneath central North Island. Since the Late Oligocene, basement exhumation in the axial ranges migrated towards the trough. Modelled thermal histories indicate significant eastwards reverse faulting on the margin-parallel Ngamatea Fault between ~27 and 20 Ma and on the Wellington-Mohaka Fault between ~20 and 10 Ma.  In contrast to the activity in the axial ranges, in western North Island, the exhumational response of the basement rocks to the Cenozoic subduction was less significant and not revealed from the present thermochronological data.  Since the Late Miocene, the exhumation rate in the axial ranges has varied significantly along-strike, lower in the centre and higher to the north and south. During the last 10 Myr, the total magnitude of exhumation has been ~4 km in the Wellington region in the south, >1 km in the Raukumara Range in the north and negligible (less than a few hundred metres) in the central axial ranges in the Hawke’s Bay region. Although the accumulation of underplated material at the basal upper plate may have contributed to the localised rock uplift and exhumation (e.g. in the Raukumara Range), margin-normal shortening of the upper plate in the forearc of the Hikurangi Margin has most likely dominated the unroofing process of the axial ranges.  In northwestern North Island, the Northland Allochthon, an assemblage of Cretaceous–Oligocene sedimentary rocks, was emplaced during the Late Oligocene–earliest Miocene, onto in situ Mesozoic and early Cenozoic rocks. Detrital zircon and apatite fission-track ages reveal that the basal Northland Allochthon sequences and the underlying Miocene autochthonous sedimentary rocks were predominantly derived from the local Jurassic terrane (Waipapa Supergrop) and perhaps the Late Cretaceous volcanics. In addition, the Early Miocene autochthon contains significant sedimentary influx from the Late Oligocene volcanics related to the subduction initiation in northern New Zealand.  Zircon and apatite fission-track data from the in situ Mesozoic basement were inverted using thermo-kinematic models coupled with an inversion algorithm. The results suggest that during the Late Oligocene, ~4–6 km thick nappes were emplaced onto the in situ rocks in the northernmost Northland region. Prior to basement unroofing in the Early Miocene, the nappes thinned towards the south. Following allochthon emplacement, eastern Northland was uplifted and unroofed rapidly over a period of ~1–6 Myr, leading to ~0.4–1.5 km erosion of the allochthon. Since the mid-Miocene, due to the decline in tectonic activity in this region, the Northland Allochthon and the underlying rocks have been eroded slowly.  This thesis has documented variable exhumation and burial processes that occurred in the upper plates of both the Mesozoic Gondwana and late Cenozoic Hikurangi subduction margins. The results provide the foundation for future studies to investigate the kinematics and mechanism of the crustal exhumation and deformation of the North Island basement in further detail.</p>

Thermal history modelling of the western margin of the Bohemian Massif using high-resolution apatite fission-track thermochronology

2020 ◽  
Author(s):  
Lucie Novakova ◽  
Raymond Jonckheere ◽  
Bastian Wauschkuhn ◽  
Lothar Ratchbacher
Keyword(s):  
High Resolution ◽  
Bohemian Massif ◽  
Thermal History ◽  
Fission Track ◽  
Track Length ◽  
Apatite Fission Track ◽  
Fission Track Thermochronology ◽  
Length Measurements ◽  
Thermal Histories ◽  
Fission Track Ages

&lt;p&gt;The Naab area is situated on the western border of the Bohemian Massif, 60 km south of the KTB (Kontinentalen Tiefbohrung). The main super-deep borehole of the KTB reached a depth of 9,101 meters in the Earth's continental crust. The fission-track data for the KTB and the Naab area present contrasting signatures. The apatite fission-track ages in the upper section of the KTB borehole and surrounding area are in the range 50-70 Ma (Wagner et al., 1994; Wauschkuhn et al., 2015). The apatite fission-track ages of the Naab basement are older than those of the KTB area, and span a broader range: 120-200 Ma (Vercoutere, 1994). The distributions of the confined-track lengths range from unimodal over skewed and mixed to bimodal, with mean lengths in the range 11-13 &amp;#181;m. In broad terms, this can be interpreted as that the Naab samples contain both an older and younger (in particular pre- and post-late Cretaceous) fission-track population. The aim of our research is to investigate the applicability of lab-based models to geological data, using improved measurement techniques.&lt;/p&gt;&lt;p&gt;We studied eighteen samples dated by Vercoutere (1994) from the Palaeozoic basement and seven large rock samples from the Rotliegend strata north of the Luhe fault.&amp;#160; We intend to extend the confined-track length measurements of Vercoutere (1994), aiming to achieve higher resolution through methodological innovations made possible by computer-controlled motorized microscopes. Improved statistics increase the resolution of the modelled thermal histories, which permits to better distinguish systematic from statistical differences between the modelled palaeotemperatures and geological estimates. Experiments have shown that the rate of length increase permits to distinguish older from younger tracks (Jonckheere et al., 2017). This allows us to distinguish between tracks formed before and after the Late Cre&amp;#173;taceous to Palaeocene exhumation. The etch rate of a confined track is also an indicator of its individual thermal history, supplementing the information gleaned from its etchable length under fixed conditions. We compiled a comprehensive, high-resolution confined-track-length dataset. The Naab thermal histories were determined using modern modelling algorithms, implementing the most recent empirical equations.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Jonckheere R., Tamer M., Wauschkuhn F., Wauschkuhn B., Ratschbacher L., 2017. Single-track length measurements of step-etched fission tracks in Durango apatite: Vorsprung durch Technik.American Mineralogist 102, 987-996.&lt;/p&gt;&lt;p&gt;Vercoutere C., 1994. The thermotectonic history of the Brabant Massif (Belgium) and the Naab Basement (Germany): &amp;#160;&amp;#160;an apatite fission track analysis. Ph. D. thesis, Universiteit Gent, pp. 191.&lt;/p&gt;&lt;p&gt;Wagner G.A., Hejl E., Van Den Haute P., 1994. The KTB fission-track project: Methodical aspects and geological implications. Radiation Measurements 23, 95-101.&lt;/p&gt;&lt;p&gt;Wauschkuhn B., Jonckheere R., Ratschbacher L., 2015. The KTB apatite fission-track profiles: building on a firm foundation? Geochimica et Cosmochimica Acta 167, 27-62.&lt;/p&gt;

scholarly journals Thermo-tectonic studies of Mesozoic basement rocks, North Island, New Zealand

2021 ◽  
Author(s):  
◽  
Ruohong Jiao
Keyword(s):  
New Zealand ◽  
Fission Track ◽  
Late Oligocene ◽  
Apatite Fission Track ◽  
Exhumation Rate ◽  
The North ◽  
Basement Rocks ◽  
Thermal Histories ◽  
Fission Track Ages

<p>The basement rocks of North Island, New Zealand, comprise metasedimentary terranes that were accreted onto the eastern Gondwana margin during Mesozoic subduction. Since the Oligocene, these terranes have been sitting at the leading edge of the Australian Plate, as the hanging wall of the Hikurangi subduction margin, overriding the subducting Pacific Plate. This thesis examines the thermo-tectonic histories of the basement rocks in North Island, using fission-track and (U-Th-Sm)/He thermochronology.  In eastern North Island, thermochronological data from the basement rocks record the exhumation histories since the latest Jurassic, related to two subduction cycles. Zircon fission-track analysis yields detrital or slightly reset ages (264–102 Ma); apatite fission-track ages range from 122 to 7.9 Ma and (U-Th-Sm)/He from 33.3 to 6.0 Ma.  In central North Island, modelled thermal histories suggest that the basement rocks were exhumed to shallow levels (<2 km) of the crust in the Early Cretaceous (~150–135 Ma). This was followed by a period of reheating until ~100 Ma, which is interpreted to be the result of burial by sedimentation above the accretionary wedge. From 100 Ma, models indicate thermo-tectonic quiescence until the Late Oligocene.  During the late Cenozoic, exhumation of the basement rocks accelerated at ~27 Ma in the western margin of the axial ranges (Kaimanawa Mountains). This acceleration in exhumation rate is interpreted to reflect the initiation of the subduction of the Pacific Plate beneath central North Island. Since the Late Oligocene, basement exhumation in the axial ranges migrated towards the trough. Modelled thermal histories indicate significant eastwards reverse faulting on the margin-parallel Ngamatea Fault between ~27 and 20 Ma and on the Wellington-Mohaka Fault between ~20 and 10 Ma.  In contrast to the activity in the axial ranges, in western North Island, the exhumational response of the basement rocks to the Cenozoic subduction was less significant and not revealed from the present thermochronological data.  Since the Late Miocene, the exhumation rate in the axial ranges has varied significantly along-strike, lower in the centre and higher to the north and south. During the last 10 Myr, the total magnitude of exhumation has been ~4 km in the Wellington region in the south, >1 km in the Raukumara Range in the north and negligible (less than a few hundred metres) in the central axial ranges in the Hawke’s Bay region. Although the accumulation of underplated material at the basal upper plate may have contributed to the localised rock uplift and exhumation (e.g. in the Raukumara Range), margin-normal shortening of the upper plate in the forearc of the Hikurangi Margin has most likely dominated the unroofing process of the axial ranges.  In northwestern North Island, the Northland Allochthon, an assemblage of Cretaceous–Oligocene sedimentary rocks, was emplaced during the Late Oligocene–earliest Miocene, onto in situ Mesozoic and early Cenozoic rocks. Detrital zircon and apatite fission-track ages reveal that the basal Northland Allochthon sequences and the underlying Miocene autochthonous sedimentary rocks were predominantly derived from the local Jurassic terrane (Waipapa Supergrop) and perhaps the Late Cretaceous volcanics. In addition, the Early Miocene autochthon contains significant sedimentary influx from the Late Oligocene volcanics related to the subduction initiation in northern New Zealand.  Zircon and apatite fission-track data from the in situ Mesozoic basement were inverted using thermo-kinematic models coupled with an inversion algorithm. The results suggest that during the Late Oligocene, ~4–6 km thick nappes were emplaced onto the in situ rocks in the northernmost Northland region. Prior to basement unroofing in the Early Miocene, the nappes thinned towards the south. Following allochthon emplacement, eastern Northland was uplifted and unroofed rapidly over a period of ~1–6 Myr, leading to ~0.4–1.5 km erosion of the allochthon. Since the mid-Miocene, due to the decline in tectonic activity in this region, the Northland Allochthon and the underlying rocks have been eroded slowly.  This thesis has documented variable exhumation and burial processes that occurred in the upper plates of both the Mesozoic Gondwana and late Cenozoic Hikurangi subduction margins. The results provide the foundation for future studies to investigate the kinematics and mechanism of the crustal exhumation and deformation of the North Island basement in further detail.</p>

Application of Apatite Fission-track Dating to the Study of Porphyry Type Mineral Deposits

1973 ◽  
Vol 10 (6) ◽  
pp. 846-851
Author(s):  
Peter A. Christopher
Keyword(s):  
British Columbia ◽  
Fission Track ◽  
Yukon Territory ◽  
Mineral Deposits ◽  
Fission Track Dating ◽  
Apatite Fission Track ◽  
Mountain Area ◽  
Thermal Event ◽  
Fission Track Ages ◽  
Apatite Fission Track Dating

Apatite fission-track ages for weakly altered rocks from the Syenite Range and Burwash Landing area of the Yukon Territory, and Cassiar area of British Columbia are shown to be consistent and generally concordant with K–Ar ages obtained on biotite from the same samples. More intensely altered rocks from Granisle Mine and the Copper Mountain area of British Columbia have discordant ages, due in part to alteration of apatite grains and, for samples from the Copper Mountain intrusions, to a Cretaceous (?) thermal event.

Apatite fission-track age correction and thermal history analysis from projected track length distributions

1993 ◽  
Vol 103 (1-4) ◽  
pp. 157-169
Author(s):  
M. Grivet ◽  
M. Rebetez ◽  
N. Ben Ghouma ◽  
A. Chambaudet ◽  
R. Jonckheere ◽  
...  
Keyword(s):  
Thermal History ◽  
Fission Track ◽  
Track Length ◽  
Apatite Fission Track ◽  
History Analysis ◽  
Age Correction
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