Tethyan Trench Tethyan Trench The Tethyan Trench was an ancient oceanic trench that existed in the northern part of the Tethys Ocean during the middle Mesozoic to early Cenozoic eras. The Tethyan Trench formed when the Cimmerian Plate was subducting under eastern Laurasia, around 200 million years ago, in the Early Jurassic. The Tethyan Trench extended at its greatest during Late Cretaceous to Paleocene, from what is now Greece to the Western Pacific Ocean. Subduction at the Tethyan Trench probably caused the continents Africa and India to move towards Eurasia, which resulted in the opening of the Indian Ocean. When the Arabian
Trench shield with a shore. While they may serve the same function, trench shoring is a different physical application that holds up the walls of a trench to prevent collapse. In the US, use of a trench shield is governed by OSHA 29 CFR Part 1926.650-.652 Subpart P-Excavations Trench shield Trench shields (also called Trench Boxes or Trench Sheets) are steel or aluminum structures used for protecting utility workers while performing their duties within a trench and avoid cave-ins. They are customarily constructed with sidewalls of varying thicknesses held apart by steel or aluminum spreaders. Spreaders can be interchanged to match the