托福 听力真题训练:Geologic Time Periods Part 1: Question 1. What is the lecture mainly about? A. Recognizing when one geologic epoch ends and another begins B. How geologists determine the age of Earth C. Whether humans have affected Earth’s climate D. Identifying elements that affect the ...
MALE PROFESSOR: As geologists, we examine layers of sediment on the Earth's surface to approximate the dates of past geologic time periods. Uh, sediment, as you know, is material like sand, gravel ⋯ fossil fragments ⋯ that is transported by natural processes, like wind, water flow, or...
What are the geologic time periods? Geologic Time: Geologic time is the way that scientists have organized the events that have impacted the formation and development of the Earth. Today, most geologic time scales begin with the Hadean Eon, which starts about 4.6 billion years ago when the sol...
Geologic time, the extensive interval of time occupied by the geologic history of Earth. Formal geologic time begins with the Archean Eon (4.0 billion to 2.5 billion years ago) and continues to the present day. Modern geologic time scales also include th
a division of geologic time longer than an epoch and included in an era a stage of culture having a definable place in time and space one of the divisions of the academic day one of the divisions of the playing time of a game
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This geologic time scale is a system used by scientists to describe Earth's history in terms of major geological or paleontological events.
The period is the basic unit of geological time in which a single type of rock system is formed. Two or more periods comprise a geological Era. Two or more Eras form an Eon, the largest division of geologic time. Some periods are divided into epochs. ...
Periods are of variable length, generally lasting tens of millions of years, with characteristic fossils found preserved in the sediments deposited during the period. It is also used to designate a characteristic of geologic time, such as the glacial period. The Columbia Electronic Encyclopedia™ ...
Interglacial periods are intervals of geologic time during which temperatures warm and glaciation retreats. They occur during ice ages. Earth is currently in an interglacial period. The last glacial period ended 11,700 years ago. How often do interglacial periods occur? Interglacial periods occur b...