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- Palaeotemperature constraints in Jabiru-1A derived from AFTA
and VR plotted against True Vertical Depth (EKB).
- Two major thermal episodes are recognised 225-160Ma (Middle
Triassic-Middle Jurassic) associated with an elevated palaeogeothermal
gradient and 30-15 Ma (Oligocene-Middle Miocene associated with
a palaeogeothermal gradient similar to that at the present-day
27.4°C/km.
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- Reconstructed thermal history of units preserved in Jabiru-1A
based on thermal history interpretation of AFTA and VR.
- Two palaeothermal episodes have been recognised, with cooling
beginning between 225 and 160 Ma (Middle Triassic to Middle Jurassic)
attributed to decline in basal heat flow combined with uplift
and erosion.
- Cooling beginning between 30 and 15 Ma (Oligocene - Middle Miocene)
attributed solely to uplift and erosion.
- Timing limits derived from AFTA samples in this well are shown
as the grey shading.
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- Variation of maturity with time for Jabiru-1A derived from
the reconstructed thermal history, with the grey columns representing
the two major thermal episodes revealed by AFTA.
- The figure shows cessation of active source rock maturation
in the deeper section at 175 Ma (225-160 Ma allowed by AFTA) due
to cooling as a response to decline in basal heat flow and minor
(600m) uplift and erosion.
- The Tertiary thermal episode has no effect on the source rock
maturation history in the deeper section, as palaeotemperatures
during this episode were less than those during the Middle Triassic-Middle
Jurassic. However, subsequent burial did result in renewed maturation
in the shallower section, with cessation of active maturation
occurring between 30 and 15 Ma.
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Basins Map || Arafura
|| Canning || McArthur
|| Bonaparte || Browse |
