SPRING DINNER MEETING
DATE: Thursday, April 12, 2018
LOCATION: Puritan Backroom (Pappas Room), Manchester
Dr. Kenneth Galli, Earth and Environmental Sciences, Boston College
New CA-TIMS Dates from the Brushy Basin Member, Morrison Formation, Western Colorado, USA: Implications for Dinosaur Evolution
Click HERE for more information.
Two new CA-TIMS U/Pb dates establish the age of the top of the Brushy Basin Member, Morrison Formation, at Flat Top (aka, Terrace Hill), north of the Fruita Paleontological Research Natural Area (FPA) and of the lower part of the Brushy Basin Member in the region of the Trail Through Time (TTT) and Mygatt-Moore Dinosaur Quarry in westernmost Colorado. Strata at both locations preserve a fossil record of large dinosaurs, including bones, dinosaur nests and trace fossils, as well as fossils of unionid bivalves, fish, turtles, crocodilians, microvertebrates, logs and other plant material. We report here a new weighted mean 206Pb/238U date of 149.43 + 0.059 Ma for three zircon grains sampled from a stratigraphic level 99 m above the base of a 101-m thick Brushy Basin Member FP section and a new weighted mean 206Pb/238U date of 150.208 + 0.094 Ma for three zircon grains sampled from a stratigraphic level 39 m above the base of a 79-m thick Brushy Basin Member TT section. These dates place the Brushy Basin strata in the Tithonian Stage of the Upper Jurassic Series. The 149.43 Ma date from Fruita is the youngest reliable date from near the top of the formation, which lends support to the idea that the eastward migration of a tectonic forebulge caused the westward tectonic beveling of the top of the Morrison Formation. The new dates also indicate a relatively short interval of deposition of the upper Brushy Basin Member of less than 1 Ma. Thus, two-thirds of the dinosaur and other vertebrate fossils known from the Morrison Formation represent a biota that existed for only 1 Ma.
5:30 pm Social Hour - 6:30 pm Dinner - 7:15 pm Speaker Presentation
For more information or to reserve a seat email Sharon Lewandowski at
CEU certificates will be available at the end of the evening program for 1.5 hours.
ADVANCE RESERVATION - Member (dues paid) $25.00 / Non-member $28.00
AT THE DOOR - Member (dues paid) $27.00 / Non-member $30.00
Student with a valid student I.D. (Reservation Required) $10.00
GSNH accepts emailed reservation requests and allows those that have reserved a seat to pay at the door. Please note that e-mail reservations constitute an agreement with the Society for which you will be responsible to pay, whether you are able to attend or not, unless you cancel your reservation by noon the Tuesday before the dinner.
Note: Please specify vegetarian meals required if registering by e-mail.
Advance Reservation Deadline is on FRIDAY April 6th.
We are a group of geologists, professional geologists and people interested in geology