location N 121,000 , E 284,000 (Cassini links), Area – 0.5 hectacres, 75 m in diameter. There is negligible tassik in this area and the cones are found in thick bush, surveys show that the mudflows cover 24 hectacres. No pebbles or boulders are seen around the eruptive centres.
The Palo Seco – Anglais Point area lies near the crest of the Southern Range Anticline. Downdip and to the north lies the Palo Seco field which produces oil from as shallow as 500 ft. The Kugler surface geological map (Fig. – anglais point colour kugler) indicates that the Upper – Lower Cruse outcrops and a number of mud volcanoes exist. Nearby coastal outcrops were examined by Lackhan et al.(2005) , foraminifera and pollen were recovered from samples. The forams indicated that the section lies in the N17-19 zone of L. Miocene – E. Pliocene age, Epistominella vitrea indicates a shallow water/abandonment facies, while the pollen, Dinos Symphonia, M. howardii, Mauritia and fern spores indicates a marine environment.
Spot surface geological map Palo Seco / Anglais point (After Kugler 1959)
Schematic cross section showing the relationship between the extruded mud and the Southern Range Anticline. Two wells APS-1 and 2 were drilled in the 1940’s in the vicinity of the mud vents (Fig 2) and their lithology is claystone dominated with minor sands. This is similar to the coastal outcrops where most of the claystones are parallel laminated and individual sands range from 2-4 ft in thickness (Plate (plate 2 cruse sediments)) . Considerable difficulty was experienced in drilling APS-1 due to the presence of mudflows near the surface. When mud weights were raised to control the mud, circulation was lost and the well had to be abandoned.
Main mud pool 22 June 2002, This is the principal vent, it has been classed as a caldera type by Barr and Saunders (1974) There is a visible oil ring in the mud and a sheen on the surrounding mud. A gas bubble is seen approximately every 10 seconds. The depth of this pool exceeds 150’ according to DeVille (2002) and the temperature is slightly below atmospheric. The temperature profile down the vent continues to be below the normal geothermal gradient, probably due to cooling of the mud by gas expansion.
The main mud pool 25 March 2003
The main pool on 4-3-2006, the thin mud has been replaced by a more viscous but well aerated mud. There is still a main point for the escape of the gas but consists of a large number of small bubbles. An oil scum is still visible.
There are 11 active cones and pools of various sizes scattered through the area. Most have appeared within the last 2 years.
The main pool on 8-June-2006, the level of mud has dropped significantly
montage showing location of vents 4 April 2009
Oil stained mud, abundant bromeliads are growing in proximity to the vents
First pool 23 October 2010
small mud vent to the south of pool
multiple small pools, note the bromeliads fringing the tassik
small cone furthest into the forest
First pool 27 march 2015
Main pool 6 April 2018