Authors: Rigo Ramírez (presenter), A. Torres, G. Jiménez, S. Carvajalino, Génesis Consultoría en Geología; G. Veloza, D. Sierra, A. Mora, HOCOL S.A
Presentation in Spanish.
The ANH-Conuco-1 is a stratigraphic well drilled by the ANH in 2013, in the northernmost San Jacinto fold belt. The well reached a total depth of 2475’ and cored Neogene units on its entirety. Based on our sedimentological analyses three lithostratigraphic intervals were defined, recording a shallowing-upwards succession, from shallow marine (shelf) to strand plain and estuarine deposits. From base to top, the lowermost Interval-1, (2245’-2475’, 229’ thickness) is composed of 59% claystones and 41% siltstones with abundant foraminifera. In this interval, two facies and one facies association were defined and interpreted as shelf deposits.The Interval-2 (384’-2245’, 1861’ thickness) is composed of sandstones (42%), mudstones (25%), siltstones (13%), muddy sandstones (8%) and sandy siltstones (6%). In general, the ichnological record exhibits null to moderate bioturbation, with Phycosiphon and Thalassinoides (several sand-filled and bivalves-filled) as the dominant trace fossils. The major sedimentological structures are even and wavy parallel lamination, with sporadic laminae of organic matter and siderite. It also has fossiliferous sandstones (6%) with bivalves and gastropods shells. Fifty facies and fourteen facies associations were determined, and were interpreted as shelf, delta and strand plain deposits. The contact between Intervals 2 and 1 is conformable gradational. Additionally, a fault zone was identified at depth 1884’- 1886’. The uppermost Interval-3 (10’-384’, 374’ thickness) is made up of mudstones (23%), sandstones (21%), siltstones (18%), limestones (16%) and muddy sandstones (7%). The ichnological record exhibits null to slight bioturbation, with Thalassinoides (filled by mollusk fragments) as the dominant trace fossil. It locally exhibits even and wavy parallel lamination. This interval contains 14% glauconitic limestones, 3% glauconitic sandstones and 8% fossiliferous sandstones. Limestones were classified as wackestone/packstone/grainstone composed of mollusk fragments and glauconite (up to 20%). Thirty facies and eleven facies associations were established. The depositional environment was interpreted from base to top as wave-dominated estuary, strand plain and delta deposits. The contact between Intervals 3 and 2 is identified as a disconformity. This study provides a unique view to the Late Neogene to Quaternary evolution of the Magdalena River paleodelta.
Bio:
Rigo Ramírez, Génesis Consultoría en Geología
Rigo earned a BSc in Geology and is a MSc Candidate.
With 18 years of experience I the industry, he currently is General Manager at Génesis Consultoría en Geología S.A.S., where he directs and supervises the development of the company's regular activities, and is also responsible for recruiting staff, selecting, orienting, and training employees, and carrying out administrative management tasks. He also leads, participates and supervises the development of sedimentological, petrographic, stratigraphic and structural analysis in drilling cores and geological mapping.
He has previous experience at Rio Tinto Mining Exploration.