The Kurgan Tradition.

From: Mark Odegard
Message: 4164
Date: 2000-10-05

My comments here are derived mostly from J.P. Mallory's article, "The Kurgan Tradition", in EIEC.
The Gimbutas theory has three waves. The first is 4500-4300 BCE, with horse-riding IEs from the Volga area expanding across Ukraine to the fringes of Central Europe.  The second is ca. 3500, as evidenced by instrusions of Steppe peoples into Moldavia and thereabouts. The third is ca 3100-2900, with stronger evidence for the presence of pastoral Steppe nomads in Romania, Thrace, as well as along the Tisza in Hungary, and especially, in the Globular Amphora culture.
I have problems with the first wave. Some rather strong statements have been made by reputable authorities that the wheel is nowhere attested before 4000 BCE. You might get bare-back riding outliers, but even 100% peaceful expansion throughout the Ukranian Steppe seems unlikely without wheeled vehicles. How do you get your infirm, your children, your pregnant women from one river valley to the next? You might get a few young adults, and non-pregnant women migrating as small groups with pack animals, but this would be peaceful diffusion.
The Kuro-Araxes culture in the Caucusus, 3500-2200 BCE, is noted for bronze and wagon-making. It is not likely to be IE-speaking (Kartvalian is more like it). Is this where the first genuinely steppe-worthy wagons and carts came from? Certainly, they would have had the good bronze tools, and plenty of Caucasian lumber, to build them.  This is also approximately the same area where the earliest war chariot is found, dating ca. 2000.
I have lots of questions, most of which cannot be answered. If one accepts a North Central European homeland, you have to explain how IE-speaker steppe-nomadism developed, and how they developed their toolkit. 
One thought I've had is the fact that the steppe grass is always greener in the west, no matter how far east you start. Hungarian grasses are the greenest of all. Steppe nomad IE-speakers would have started with the best grasses, and their herds would have thrived, as would they themselves. It would be initial conditions experienced by founders sustaining themselves for millennia.