Salt Tectonics at the Lusitanian Basin
Tuesday, May 1, 2018
8:00 a.m. - 7.00 p.m.
Lusitanian Basin (Western Portugal)
Who Should Attend
Geologists and geophysicists interested in looking at seismic-scale outcrops and landscapes related with piercing diapirs.
- To discuss structural and stratigraphic issues related to salt tectonics.
- To observe and analyse landscape features related to piercing diapirs.
- To discuss its impact on regional petroleum systems and plays.
About Field Trip
This field-trip will visit different situations of piercing diapirs at the Lusitanian Basin (Western Portugal). Diapirs are controlled by basement’s NNE-SSW tardi-variscan fractures and its Mesozoic reactivation. Vertical movements were related mostly with the Late Jurassic main rifting, subsidence and overburden phase, whereas piercing has been attained in Late Cretaceous times, related to the beginning of inversion and alpine compression.
Vertical salt-walls exhibit straight geometries mostly aligned and elongated according to those basement fractures, sometimes with doleritic intrusions. Smaller diapirs exhibit circular to sigmoidal geometries clearly related to transtension. The present-day configuration of the Lusitanian Basin is highly controlled by salt tectonics creating many structural traps, with oil-shows and oil-seeps clearly related with it.
This field-trip will visit several piercing diapirs, to observe their geomorphological and structural features. Seismic lines will also be showed, to analyse sub-surface features and compare them with the field observations. Diapirs configuration and its influence on the basin’s petroleum systems will be discussed and integrated on a regional scale approach.
- Departure from Lisbon at 8.00 from Conference Hotel (Sana Malhoa)
- Road to Rio Maior (1h15m, mostly highway). Observation of the Alcobertas salt-wall and Portela igneous intrusions. Visit to historical salt-pans exploration (Salinas).
- Road to São Martinho do Porto (45 min). Observation of a seismic-scale bay with a piercing diapir and deformed Late Jurassic layers.
- Road to Óbidos (30 mins). Observation of a “diapiric valley” with its main lithological and structural features (deformed walls and floating dolomitic rafts).
- Road to Vimeiro (30 mins). Observation of a small piercing diapir with its related deformation. 5 km further to Santa Cruz and observation of a large-scale piercing diapir, with its structural features and influence on Late Jurassic sedimentation.
- Road to Lisbon (1 hour, mostly highway). Arrival at the meeting point around 7 pm (before sunset time).
Departure Time and Place
Location: Conference Venue, Hotel Sana Malhoa
Departure Time: 8:00 a.m.
Ground transportation, refreshments, lunch and guidebook.
Transportation to start point is not included in the costs of this trip. Temperatures can range from 54 to 72 degrees Fahrenheit during this time period. Please bring clothing for hot day time temperatures (sun hat/ sun glasses/ sun cream etc.) Participants should wear light trekking shoes.