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Recent Geotrack Papers
S.P. Holford, J.P. Turner, P. F. Green (2005). Reconstructing the Mesozoic - Cenozoic exhumation history of the Irish Sea basin system using Apatite Fission Track Analysis and Vitrinite Reflectance data Petroleum Geology: North-West Europe and Global Perspectives - Proceedings of the 6th Petroleum Geology Conference pp. 1095–1107. (pdf)
Bibliography of AFTA and related topics.
Abstracts
Multiphase cooling and exhumation of the southern Adelaide Fold Belt constrained by thermal history modelling of apatite fission track data.
HELEN J. GIBSON1 & KURT STÜWE2
1Geotrack International, 37 Melville Road, Brunswick West, Victoria, 3055, Australia
2Department of Earth Sciences Monash University, Clayton Victoria, 3168, AustraliaAbstract
Results from apatite fission track analysis (AFTA®) are presented for 20 outcrop samples collected across two main east-west zones in the southern Adelaide Fold Belt, South Australia. Fission track age and length distributions in all samples are consistent with at least two cooling events: An event beginning some time between 85 and 0 Ma (Late Cretaceous to Recent) which was characterised by cooling throughout the study area from roughly 50-70°C, and an event beginning some time between 300 and 270 Ma (Late Paleozoic) which was characterised by cooling below temperatures >110°C in all areas except for the Mt Lofty Ranges and Murray Bridge region where peak temperatures were only 100-120°C prior to cooling. Some samples from this sub-region of relatively cool Late Paleozoic temperatures also retain evidence for an even earlier cooling event from temperatures >120°C, beginning some time prior to 350 Ma. We interpret the Late Cretaceous-Recent cooling event as due to region-wide exhumation from a total depth of 1.0 to 1.6 km (assuming a paleogeothermal gradient of 35°C/km and paleo-surface temperature of 15°C). This event (perhaps comprising several pulses) appears to have been longer-lasting and wider-reaching in its thermal effect, compared to the well recognised uplift event in the Cenozoic which is thought to be responsible for the present-day topography of the Mt Lofty and Flinders Ranges. The Late Paleozoic event, recognised using AFTA, is interpreted as cooling associated with termination of the Alice Springs Orogeny, while cooling prior to 350 Ma probably represents the final stages of Early-Middle Paleozoic unroofing of the southern Adelaide Fold Belt.
Basin Analysis In press.
Evidence from apatite fission track analysis for the post-Devonian burial and exhumation history of the northern Highlands, Scotland
K. Thomsona , J.R. Underhillb , P.F. Greenc, R.J. Brayd, H.J. Gibsonc
aDepartment of Geological Sciences, University of Durham, South Road, Durham, U.K.
bDepartment of Geology and Geophysics, The University of Edinburgh, Grant Institute, West Mains Road, Edinburgh, U.K.
cGeotrack International, 37 Melville Rd, Brunswick West, Victoria 3055, Australia
dGeotrack International, No. 5 The Linen Yard, South Street, Crewkerne, Somerset, U.K.Abstract
Devonian and older rock samples from outcrops in the northern Scottish Highlands have undergone protracted cooling since they reached palaeotemperatures of ~110ºC or more in the Late Paleozoic to Early Mesozoic. The results not only suggest that the northern Highlands region has experienced kilometre-scale exhumation since the Late Paleozoic, but also that Devonian and possibly Permo-Carboniferous sedimentation was probably more extensive than current outcrop patterns would imply. A Permian outcrop sample from the Minches Basin reached a maximum palaeotemperature of 70-90ºC prior to the onset of cooling in the Early Tertiary, while data from Devonian and older samples suggest an acceleration in the rate of cooling in the Early Tertiary. The magnitude of Early Tertiary palaeotemperatures on the mainland adjacent to the Inner Moray Firth (IMF) indicate similar amounts of Tertiary exhumation to those derived from compaction analyses for the IMF. However, to the west, the magnitude of Tertiary cooling cannot be solely ascribed to exhumation and a contribution of heating due to hydrothermal effects and/or elevated heat flow associated with the Tertiary Igneous Complex may also need to be invoked.
Marine and Petroleum Geology 16 (1999) 27-39
Dating and duration of hot fluid flow events determined using AFTA® and vitrinite reflectance-based thermal history reconstruction
IAN R. DUDDY1, PAUL F. GREEN1, KERRY A. HEGARTY1, RICHARD J. BRAY2 & GEOFFREY W. O'BRIEN3
1Geotrack International Pty Ltd, 37 Melville Rd, Brunswick West, Victoria 3055, Australia
2Geotrack International (UK), Unit 14, Crewkerne Business Park, South Street, Crewkerne, Somerset, TA18 7HJ, UK.
3Australian Geological Survey Organisation - Marine Petroleum and Sedimentary Resources Division, GPO Box 378 Canberra, ACT, 2601
Abstract: Heating due to lateral introduction of hot fluids is becoming an increasingly recognized feature of the thermal histories of sedimentary basins. In some basins, heating by fluids may have an important effect on hydrocarbon source rock maturation history, so that quantification of the magnitude and timing of heating become essential elements in hydrocarbon prospectivity. In other cases, determining the time of fluid heating in a reservoir may provide a key constraint on hydrocarbon migration history. Examples are presented using AFTA apatite fission track analysis and vitrinite reflectance (VR) data to identify and quantify fluid heating in well sequences from several regions. In the West of Shetland region, in the vicinity of the Rona Ridge, non-linear palaeotemperature profiles defined by AFTA and VR results provide evidence of local heating shallow in the section. AFTA timing constraints suggest introduction of heated fluids produced by nearby Tertiary intrusive activity, although the time constraints are broad because of the low maximum palaeotemperatures involved (R0max < 0.6%). In a well from Asia, transient maximum palaeotemperatures > 120ºC resulted in R0max > 0.6% in an Eocene section, with AFTA constraining the fluid flow event responsible to the early - mid Miocene (25 to 10 Ma). On the North West Shelf of Australia transient fluid flow associated with hydrocarbon leakage, and possibly charge, has been previously identified by a combination of AFTA, VR and fluid inclusion homogenization temperature (Th) results. In the East Swan-2 well, a fracture inclusion in quartz from shallow Eocene sandstones gives a maximum Th value of 88ºC, c. 40ºC higher than the present temperature. AFTA and VR data show no direct evidence of sustained heating at such a temperature, and can only be reconciled if the duration of heating was c. 20 000 years. The results are consistent with this event being associated with passage of a hot brine and hydrocarbon fluid (O'Brien and Woods, 1995). These case studies demonstrate that a combination of thermal history tools can be used to identify and quantify the thermal effect of fluid flow, potentially allowing much tighter constraints on hydrocarbon generation and migration histories.
Geological Society, London, Special Publications, 144, 41-51.
An investigation of the thermal history of the Ahnet and Reggane Basins, Central Algeria, and the consequences for hydrocarbon generation and accumulation
PAUL LOGAN1 & IAN DUDDY2
1BHP Petroleum, Neathouse Place, London SW1V 1LH, UK
2Geotrack International, 37 Melville Rd, Brunswick West, Victoria 3055, AustraliaAbstract: In an attempt to better understand the thermal history of the Ahnet and Reggane Basins, the techniques of apatite fission track analysis and zircon fission track analysis were employed on samples from a number of exploration wells previously drilled in the study area. The results indicated clear evidence for a major heating event at c. 200 Ma, overprinted on the effects of heating caused by simple burial before the Hercynian uplift. It is proposed that at least two major phases of hydrocarbon generation took place within the study area; an early, pre-Hercynian phase, in which chiefly liquid hydrocarbons were expelled and a later phase, associated with a 'heat spike' at c. 200 Ma, in which significant quantities of dry gas were generated and expelled.
Petroleum Geology of North Africa. Geological Society, London, Special Publication no. 132, 1998, P.131-155.
Source Rock Burial History and Seal Effectiveness: Key Facets to Understanding Hydrocarbon Exploration Potential in the East and Central Irish Sea Basins
William I. Duncan1, Paul F. Green2, and Ian R. Duddy2
1Deminex UK Oil and Gas Ltd, Bowater House, 114 Knightsbridge, London, SW1X 7LD, UK
2Geotrack International, 37 Melville Rd, Brunswick West, Victoria 3055, AustraliaAbstract
The timing of hydrocarbon generation from Carboniferous source rocks and the lack of evaporites within the Triassic Mercia Mudstone Group seal sequence have contributed significantly to the lack of exploration success in the Triassic Sherwood Sandstone play of the Central Irish Sea Basin. Apatite fission track analysis (AFTA®), combined with vitrinite reflectance data from the Central Irish Sea Basin and adjacent areas, indicates that maximum burial and heating of the Carboniferous section was achieved by the Early Cretaceous. The long residence period for trapped hydrocarbons generated in the Early Cretaceous, combined with the ineffectiveness of the Mercia Mudstone Group seal caused by the absence of annealing halites and the presence of thief sandstones, led to hydrocarbon loss through trap breaching during subsequent tectonic events. In contrast, maximum burial of Carboniferous source rocks in the central East Irish Sea hydrocarbon province was achieved in the Late Cretaceous - Early Tertiary, giving a shorter residence period for generated hydrocarbons. The combination of a short residence period and the presence of a halite-bearing Mercia Mudstone seal sequence significantly improved hydrocarbon retention within the Sherwood Sandstone reservoir. If traps were episodically breached during the late Tertiary, they were recharged by the inversion process, which caused gas expansion, spill from charged traps, and lateral remigration of hydrocarbons updip. The inversion-related pressure drop also caused retrograde condensate dropout from gas accumulations to provide a supply of late condensate for preferential spill and remigration.
AAPG Bulletin, V.82, No. 7 (July 1998), P.1401 - 1415.