Age, origin and thermal history of the Capoas intrusion, Palawan
Mike Cottam and Marnie Foster
This project aims to further understand Palawan’s tectonic history by investigating the age, origin and thermal history of the granitic Capoas intrusion in northern Palawan. The mineralogy of the Capoas intrusion provides a rare opportunity to date a single geological unit using a range of complementary geochronological and thermochronological techniques, and to develop a detailed thermal history representative of northern Palawan.
Key questions include:
- What is the age and origin of the Capoas intrusion?
- Can the previously proposed Middle Miocene age be confirmed?
- Was the intrusion emplaced in a single event? Or does it reflect multiple, possibly pulsed, intrusion?
- What tectonic processes does the intrusion represent?
- What can the thermal history of the Capoas intrusion reveal about the Neogene tectonic history of the region?
- Did Palawan experience significant exhumation in the Late Miocene and Pliocene, as seen in northern Borneo?
- Did Palawan form — along with northern Borneo — a part of large emergent area in the Late Miocene and Pliocene?
- Does the Capoas intrusion record significant extension within the region in the Late Miocene and Pliocene?
This project aims to apply a full suite of geochronological and thermochronological techniques to samples collected from the Capoas intrusion. Techniques applied will include:
- U-Pb SIMS (Secondary Ionisation Mass Spectrometry) dating of zircon
- 40Ar/39Ar dating of white mica, biotite mica and possibly K-feldspar
- (U-Th)/He dating of zircon and apatite