GE 142 & GE 251 SPRING 2004 FIELD TRIP

GEOLOGY OF NOVA SCOTIA & NEW BRUNSWICK



BACK ROW (L to R): Elissa Baim '05, Nick Bazarian '07, Alex Humphrey '05, Liz Mollo-Christensen '06, Marcy Rolerson '06, Kate Lidington '06, Heather Hansman '05, Nate Quigley '05, Ian Cochran '04.    
MIDDLE ROW: Robin Nesbeda '04, Chris Russoniello '06, Dr. Bruce Rueger.    
FRONT ROW: Dr. Robert Gastaldo, Mike Avery '06, Anna Bumby '06, Adelle Donohue '07, Betsy Littlefield '07, Anna Barensfeld '07, John Goss '06

Early Pennsylvanian (Late Carboniferous) Rocks at Joggins, Nova Scotia

The Carboniferous rocks exposed along the Bay of Funday at Joggins, Nova Scotia, provides one of the most extensive rock records of the Mississippian to Pennsylvanian transition from Greenhouse to Icehouse conditions.  The Joggins section is world renown for its' extensive fossil record that includes numerous erect standing forests, millipede trackways, unique freshwater assemblages including large bivalves (clams), and tetrapods that include the earliest recorded reptiles.  The Canadian government in Ottowa announded on 30 April 2004 that Joggins has been selected for consideration as an UNESCO World Heritage site because of it's significant geological and paleontological features.  Dr. John Calder of the Nova Scotia Department of Natural Resources has been working for the past decade  heading the Joggins Committee.  Dr. Calder led Colby students through the exhibits at the Bay of Fundy Geology Museum and the Joggins section.


Dr. John Calder (right) provides an overview of the Geology of Nova Scotia, pointing out the transform fault emplaced during the Acadian orogeny, the development of tensional basins filled during the Carboniferous, and the subsequent rift systems in the Late Triassic.

Photography by Alex Humphreys '05


Dr. John Calder lecturing on site about the transition from warm, dry and seasonally wet conditions found low in the section  near Lower Cove to the  seasonally ever-wet conditions typical of the Joggins Formation.

Dr. Bruce Rueger and students examine the rock debris that has fallen from the cliffs during the winter months.  Various kinds of fossils (compressions & impressions; casts & molds) are found in the rocks at the base of the cliffs.

GE142 and GE251 students search the sandstone river deposits for fossil plants preserved in the bottom of channels.  Most fossils are preserved as internal pith casts of Calamites stems (horsetails) or as casts of extinct Lepidodendrales (club mosses).

Dr John Calder examines one of the many standing lycopsid (club moss) trees exposed in the Joggins cliff face near Coal Mine Point.  This tree is  preserved as a sandstone cast for approximately 2 meters in height.  You can see the tree's rooting system  (known as Stigmaria) directly above Dr. Calder's right hand.  This tree was rooted in the top of the sandy channel deposit and buried by a mix of sand and mud induced by a coseismic change in base level.  
Lycopsid trees are now extinct, but were composed of an unique anatomical organization.  The tree had very little wood, restricted to the center of the plant. A  three-parted bark surrounded the conductintg tissue. Following burial, the softer tissue of the bark rotted while the more resistant outer bark tissues retained the overall shape of the tree.  The hollow that developed was filled subsequently with additional sediment, resulting in the tree cast.
Joggins is famous because the earliest known reptiles are preserved in these tree casts.


Two of the spectacular fossils found during the field trip are traded. Dr. Gastaldo (right) holds on dearly to a large compression fossil of part of a gymnosperm ("seed fern") leaf, while Dr. Calder (left) holds a footprint of an early tetrapod.

Photography by Alex Humphreys '05
View looking North across the interval in which the Fundy Seam Fossil forests are preserved.  Within this 37-m thick interval, from Coal 32 to Coal 29, some of the finest examples of fossil lepidodendron forests occur.  There are 49 different horizons at which erect trees occur.  The tallest trees are up to 3 m in height and up to 1 m in diameter.


Rocks exposed at Coal Mine or Hardscrabble Point  preserve an unusual set of trace fossils (ichnofossils) seen here at the Bay of Fundy Geology Museum in Parrsboro.  These trails are of the gigantic myriapod (millipede) called Arthropleura. Mike Avery '07 serves as scale.

And what would a museum stop be without Dino headware?  Ann Bumby '07 and Adelle Donohue '07 model the latest in Earth Science fashion statement.


Early Mississippian (Early Carboniferous) Rocks in New Brunswick


A forthcoming paper by Dr. Howard Falcon-Lang, University of Bristol, documents standing forests in the Early Mississippian rocks of New Brunswick, Canada.  These forests differ from those preserved at the classic Joggins locality, and mark the colonization by these trees in coastal swamps.   The Early Mississippian rocks were deposited during the onset of the Icehouse that characterizes the Late Pennsylvanian sequences at Joggins.


The Early Mississipian section exposed along Canadian Highway 1 near Norton, New Brunswick consists of nearly sub-vertical beds (83-90 dip) that strike sub-parallel to the road.  As such, the bedding surfaces of the rocks can be seen easily.  These rocks have been strongly deformed with large-scale isoclinal folds and normal faults occurring in the section.

The fossil-bearing rocks along Highway 1 are composed of nine (9) different sedimentary facies.  These sequences record deposition in three different nearshore and coastal plain setting.  Wave-dominated delta-front deposits are overlain by poorly drained delta deposits representing an ever wet climate.  Immediately overlying the wetlands is a sequence of rock that indicates a well-drained alluvial plain setting.  These rocks record a different climate signature, one in which seasonally dry  conditions prevailed.


Early Mississipian Rocks exposed in New Brunswick record deposition from nearshore marine environments, such as these shallow-water ripple structures, to coastl swamps in which early lycopsid trees are preserved in growth position.  John Goss '06 as scale.

Lycopsid trees related to those found at Joggins are preserved in growth position along with their rooting structures.  Lepidodendropsis was a much smaller tree with a cormose (think tulip or daffodil-type bulb) base and a short trunk. Rooting structures radiate from the central corm in this picture. These trees lived in a swamp in which the soil was muddy. Hammer is for scale.