The document discusses the application of micropaleontology in paleogeography. Micropaleontology provides important records of global environmental change through deep sea sediments. Paleogeography involves reconstructing features of the ancient Earth such as mountain belts, climate zones, and positions of continents and ocean basins. Techniques used in paleogeographic studies include paleomagnetism, which can determine the latitude of rock deposition, and analysis of fossils to infer biogeography. The document also summarizes paleogeography during the Cretaceous period and Cambrian period.

1. APPLICATION
MICROPALEONTOLOGY IN
PALEOGEOGRAPHY
BY:
THOMAS CHINNAPPAN . A ,
M.SC.APPLIED GEOLOGY,
PERIYAR UNIVERSITY,
SALEM.

2. INTRODUCTION
 The application of micropaleontology is crucial to exploration ,
appraisal and field development studies and impacts on drilling
problems (such as coring point selection and terminal depth decisions.
 Microfossils are especially notworthy for their importance in for
biostratigraphy.
 Microfossils , particularly from deep sea sediments ,also provide some
most important records of global environment change (or) long.

3. PALEOGEOGRAPHY
 The ancient geography of Earth’s surface . Earth ‘s geography is constantly
changing : continents move as a result of plate tectonic interactions.
 Mountain ranges are thrust up and erode; and sea levels rise and fall as the
volume of the ocean basins change.
 These geographic changes can be traced through the study of the rock
and fossil record.
 The study of palaeography has evolved from simple continental of
reconstructions to more sophisticated paleocontinental maps.

4.  Paleogeography is thus an essential component of an earth
systems approach to interpreting the geologic past.
 A Broad range of geologic elements can be reconstructed
through paleogeographic studies, such as mountain belts, climate
zones, and the emergent land.
 Paleoconfigurations of continents and ocean basins are
determined by a variety of techniques. Paleomagnetic studies are
the most common, but additional constraints are provided by
faunal provincialism (biogeography) and abiotic continental
linkages such as pre-break-up magmatism

5. Paleomagnetism
 the remanent magnetic field often preserved in rocks containing iron-
bearing minerals, paleomagnetic analysis can determine whether a rock
was magnetized near one of Earth’s poles or near the Equator.
 Iron-bearing minerals forming in igneous rock align themselves
with Earth’s magnetic field as the molten rock cools
 Therefore, iron-bearing minerals formed or deposited at low latitudes
will be nearly parallel to Earth’s surface, while those at high latitudes will
dip steeply. If the rocks are later transported by tectonic processes, their
original latitude of deposition can be determined by their orientation.

6. Paleoclimatology
 Earth’s climate is primarily a result of the redistribution of the Sun’s energy
across the surface of the globe
 It is warm near the Equator and cool near the poles. Wetness or rainfall also
varies systematically from the Equator to the pole in alternating bands
 It is wet near the Equator, dry in the subtropics, wet in the temperate belts,
and dry near the poles. Certain kinds of rocks form under specific climatic
conditions. For example, coals occur where wet climates once supported
lush vegetation; bauxite (the principal ore of aluminum) is formed in warm
and wet conditions, evaporites and calcretes require warmth and aridity to
form; and tillites are deposited during the movement of glacial ice.

7. Continents and ocean basins
 The two major paleogeographic features are the
continents and the ocean basins. Since
early Precambrian time, Earth has been divided into
deep ocean basins (average depth, 3.5 km, or 2.2
miles) and high-standing continents (average
elevation, about 800 metres, or 2,600 feet).
 Continental lithosphere stands high above the
ocean basins because it is less dense and is not
easily subducted, or recycled back into Earth’s
interior.

8. Paleographic reconstruction
during the createous
 The Cretaceous is the longest period of the
Phanerozoic Eon. Spanning 79 million years, it
represents more time than has elapsed since the
extinction of the dinosaurs, which occurred at the
end of the period. The name Cretaceous is derived
from creta, Latin for “chalk,” and was first proposed
by J.B.J.

10. Global paleogeography during the
cambrain

11.  Paleogeography. The geography of the Cambrian world
differed greatly from that of the present day. ... Distribution of
landmasses, mountainous regions, shallow seas, and deep
ocean basins during the Late Cambrian. Included in the
paleogeographic reconstruction are cold and warm ocean
currents.
 A large scale global warming trend.
 A receding of the Pre-Cambrian ice age - allowed for warmer
more oxygenated seas.
 An increased capacity to foster life then arose.
 In this environment there was an unimaginable radiation of
species.

12. Agents of paleogeographic change
 The ancient distribution of land and sea, probably the single most
important aspect of paleogeography, is a function of both
continental topography and sea-level change
 The last glacial maximum was 18,000 years ago. Other important global
episodes of glaciation occurred 300 million, 450 million, and 650 million
years ago. The oldest known glacial episode occurred in the Precambrian,
approximately 2.2 billion years ago
 For the last 20 million years, the continents and their margins have been
largely high and dry because there has been a significant amount of ice
on Antarctica and there has been extensive mountain-building in Asia.

13. Thank you